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Background Intra-rectal artesunate has been developed as a potentially life-saving treatment of severe malaria in rural village settings where administration of parenteral antimalarial drugs is not possible. We studied the population pharmacokinetics of intra-rectal artesunate and the relationship with parasitological responses in patients with moderately severe falciparum malaria. Methods and Findings Adults and children in Africa and Southeast Asia with moderately severe malaria were recruited in two Phase II studies (12 adults from Southeast Asia and 11 children from Africa) with intensive sampling protocols, and three Phase III studies (44 children from Southeast Asia, and 86 children and 26 adults from Africa) with sparse sampling. All patients received 10 mg/kg artesunate as a single intra-rectal dose of suppositories. Venous blood samples were taken during a period of 24 h following dosing. Plasma artesunate and dihydroartemisinin (DHA, the main biologically active metabolite) concentrations were measured by high-performance liquid chromatography with electrochemical detection. The pharmacokinetic properties of DHA were determined using nonlinear mixed-effects modelling. Artesunate is rapidly hydrolysed in vivo to DHA, and this contributes the majority of antimalarial activity. For DHA, a one-compartment model assuming complete conversion from artesunate and first-order appearance and elimination kinetics gave the best fit to the data. The mean population estimate of apparent clearance (CL/F) was 2.64 (l/kg/h) with 66% inter-individual variability. The apparent volume of distribution (V/F) was 2.75 (l/kg) with 96% inter-individual variability. The estimated DHA population mean elimination half-life was 43 min. Gender was associated with increased mean CL/F by 1.14 (95% CI: 0.36–1.92) (l/kg/h) for a male compared with a female, and weight was positively associated with V/F. Larger V/Fs were observed for the patients requiring early rescue treatment compared with the remainder, independent of any confounders. No associations between the parasitological responses and the posterior individual estimates of V/F, CL/F, and AUC0–6h were observed. Conclusions The pharmacokinetic properties of DHA were affected only by gender and body weight. Patients with the lowest area under the DHA concentration curve did not have slower parasite clearance, suggesting that rectal artesunate is well absorbed in most patients with moderately severe malaria. However, a number of modelling assumptions were required due to the large intra- and inter-individual variability of the DHA concentrations., A study of the population pharmacokinetics of intra-rectal artesunate in patients with moderately severe falciparum malaria found the pharmacokinetic properties of dihydroartemisinin were affected only by gender and body weight., Editors' Summary Background. More than 40% of the world's population is at risk of malaria, a tropical parasitic disease that is transmitted between people by infected mosquitoes. Malaria parasites cause a 'flu-like illness that includes chills, fevers, headaches, and sometimes nausea and vomiting. If untreated, people with malaria can rapidly become anemic—the parasite destroys their red blood cells—or can develop complications that damage the brain and other organs. Severe malaria can be fatal and must be treated quickly. It has become a matter of great concern that the parasite has developed resistance to most of the drugs used to treat or prevent malaria. In the past few years, artemisinin derivatives have been shown to be an effective new form of treatment. Artemisinin derivatives are effective, rapid-acting antimalarial drugs—wormwood, the plant source of artemisinin, is an ancient Chinese cure for malaria. Artesunate, a water-soluble derivative of artemisinin, can be given as tablets or as injections. However, people with severe malaria often cannot take oral medicines, and in rural settings in the developing world, artesunate injections are usually impracticable. Consequently, rectal artesunate suppositories have been developed to provide first-line treatment of severe malaria in these settings. This simple dosing method can “buy” patients valuable time during which they can be moved to a hospital for further treatment. Why Was This Study Done? When treating severe malaria, it is important that every patient absorbs the antimalarial drug rapidly and efficiently into their blood. If even a small proportion of patients malabsorb the drug, many people could die. How the body processes a drug is known as pharmacokinetics, and although some pharmacokinetic studies have investigated how the body processes artesunate given in rectal suppositories, relatively little is know about the population pharmacokinetics of artesunate given this way. That is, the patient characteristics that affect the processing of intra-rectal artesunate are not known, and it is unclear whether a small proportion of the population might fail to absorb the drug given via this route. In this study, the researchers have developed and tested a population pharmacokinetic model for artesunate given rectally to children and adults with moderately severe malaria. What Did the Researchers Do and Find? The researchers took serial blood samples from nearly 200 patients with moderately severe malaria in Africa and Southeast Asia for the first 24 hours after they received a rectal artesunate suppository. They measured the levels of artesunate and dihydroartemisinin (DHA; the body rapidly converts artesunate to DHA, which kills the malaria parasites) in these samples and used these data to build a pharmacokinetic model for how the body processes. Averaged out across the patients, they calculated, for example, that half of the drug present absorbed was eliminated within 43 minutes. To find out whether any patient characteristics affected the pharmacokinetics of intra-rectal artesunate, the researchers used their model to estimate the clearance of DHA from the body and the ability of DHA to spread through the body (so-called apparent volume of distribution) for the study patients. This analysis showed that only gender and weight affected DHA pharmacokinetics. Finally, the researchers showed that how well the parasite was cleared from the patients was not related to these pharmacokinetic parameters, although the need for earlier rescue treatment was associated with a larger volume of distribution for DHA. Importantly, the parasitological response was not affected by the estimated cumulative amount of DHA absorbed into the blood during the first six hours after treatment. What Do These Findings Mean? The data presented in this study indicate that individual patients processed artesunate very differently in terms of how they absorbed the drug and how it spread around the body. Even so, the maximal effects of artesunate on the malaria parasite were achieved rapidly in nearly all the patients. This and other pharmacokinetic findings must be interpreted with caution, warn the researchers, because their model included many assumptions to allow, for example, for the variability of DHA concentrations both within individual patients and between patients. Nevertheless, the findings provide important clues about which patient characteristics might cause early treatment failure, and indicate that artesunate is sufficiently well absorbed via the rectal route in most patients to make artesunate suppositories a promising first-line treatment for moderately severe malaria. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0030444. • World Health Organization links to general information on malaria plus specific information on rectal artesunate • MedlinePlus encyclopedia entry on malaria • US Centers for Disease Control and Prevention information on malaria for patients and professionals • Wikipedia pages on malaria and artemisinin (note that Wikipedia is a free online encyclopedia that anyone can edit)

Sepsis is a progressive injurious process resulting from a systemic inflammatory response to infection [1]. In developed countries, sepsis is an important cause of mortality: in the United States alone, up to 750,000 people annually suffer from severe sepsis—mostly bacterial in aetiology—of whom 29% may die [2,3]. Unfortunately, data on bacterial sepsis in developing countries are notably lacking, particularly in adults. Estimates of the burden of lower respiratory tract infections, meningitis, and “other infections”, of which a significant proportion are associated with severe sepsis, show that the majority of deaths and disability-adjusted life years lost occur in low-income countries (Figure 1) [4]. Additionally, severe sepsis is likely to complicate a varying proportion of cases of malaria, HIV/AIDS, diabetes, maternal conditions, and cancer deaths globally.

Background Treatment of asymptomatic individuals, regardless of their malaria infection status, with regularly spaced therapeutic doses of antimalarial drugs has been proposed as a method for reducing malaria morbidity and mortality. This strategy, called intermittent preventive treatment (IPT), is currently employed for pregnant women and is being studied for infants (IPTi) as well. As with any drug-based intervention strategy, it is important to understand how implementation may affect the spread of drug-resistant parasites. This is a difficult issue to address experimentally because of the limited size and duration of IPTi trials as well as the intractability of distinguishing the spread of resistance due to conventional treatment of malaria episodes versus that due to IPTi when the same drug is used in both contexts. Methods and Findings Using a mathematical model, we evaluated the possible impact of treating individuals with antimalarial drugs at regular intervals regardless of their infection status. We translated individual treatment strategies and drug pharmacokinetics into parasite population dynamic effects and show that immunity, treatment rate, drug decay kinetics, and presumptive treatment rate are important factors in the spread of drug-resistant parasites. Our model predicts that partially resistant parasites are more likely to spread in low-transmission areas, but fully resistant parasites are more likely to spread under conditions of high transmission, which is consistent with some epidemiological observations. We were also able to distinguish between spread of resistance due to treatment of symptomatic infections and that due to IPTi. We showed that IPTi could accelerate the spread of resistant parasites, but this effect was only likely to be significant in areas of low or unstable transmission. Conclusions The results presented here demonstrate the importance of considering both the half-life of a drug and the existing level of resistance when choosing a drug for IPTi. Drugs to which little or no resistance exists are not advisable for IPT in high-transmission areas, but IPTi is not likely to significantly impact the spread of highly resistant parasites in areas where partial resistance is already established. IPTi is more likely to accelerate the spread of resistance in high-transmission areas than is IPT in adults (i.e., pregnant women)., A new malaria model predicts that deploying intermittent preventive treatment (IPT) in infancy could accelerate the spread of resistant parasites, but that this effect would be significant only in areas of low or unstable transmission.

A better understanding of the pharmacodynamics of intermittent presumptive treatment, says White, will guide more rational policymaking, A better understanding of the pharmacodynamics will guide more rational policymaking

The production of substandard and fake drugs is a vast and underreported problem, particularly affecting poorer countries. It is an important cause of unnecessary morbidity, mortality, and loss of public confidence in medicines and health structures. The prevalence of counterfeit drugs appears to be rising (see “The Scale of the Problem”) and has not been opposed by close cooperation between drug companies, governments, or international organizations concerned with trade, health, customs and excise, and counterfeiting. In this article we suggest that many pharmaceutical companies and governments are reluctant to publicize the problem to health staff and the public, apparently motivated by the belief that the publicity will harm the sales of brand-name products in a fiercely competitive business. Publicly, at least, several industry sources say the justification for secrecy is to avoid any alarm that could prevent patients taking their genuine medicines. We argue that this secrecy, and the subsequent lack of public health warnings, is harming patients and that it is also not in the long-term interests of the legitimate pharmaceutical industry. We urge a change to mandatory reporting to governmental authorities, which should also have a legal duty to investigate, issue appropriate public warnings, and share information across borders. This is not a role for the pharmaceutical industry, which has a serious conflict of interest. While some drug companies have given public warnings to protect patients, others have been criticized for withholding information and, in a recent development in the United States, taken to court for failing to act. The industry is addressing the problem. In 2003, US pharmaceutical companies made an agreement with the US Food and Drug Administration (FDA) that they would report suspected counterfeit drugs to the FDA within five days of discovery (see “Companies That Have Warned”), although this remains a voluntary arrangement. In many poorer countries, where the problem is at its worst, there are no similar governmental and industry initiatives.

Background Health indicators are poor and human rights violations are widespread in eastern Burma. Reproductive and maternal health indicators have not been measured in this setting but are necessary as part of an evaluation of a multi-ethnic pilot project exploring strategies to increase access to essential maternal health interventions. The goal of this study is to estimate coverage of maternal health services prior to this project and associations between exposure to human rights violations and access to such services. Methods and Findings Selected communities in the Shan, Mon, Karen, and Karenni regions of eastern Burma that were accessible to community-based organizations operating from Thailand were surveyed to estimate coverage of reproductive, maternal, and family planning services, and to assess exposure to household-level human rights violations within the pilot-project target population. Two-stage cluster sampling surveys among ever-married women of reproductive age (15–45 y) documented access to essential antenatal care interventions, skilled attendance at birth, postnatal care, and family planning services. Mid-upper arm circumference, hemoglobin by color scale, and Plasmodium falciparum parasitemia by rapid diagnostic dipstick were measured. Exposure to human rights violations in the prior 12 mo was recorded. Between September 2006 and January 2007, 2,914 surveys were conducted. Eighty-eight percent of women reported a home delivery for their last pregnancy (within previous 5 y). Skilled attendance at birth (5.1%), any (39.3%) or ≥ 4 (16.7%) antenatal visits, use of an insecticide-treated bed net (21.6%), and receipt of iron supplements (11.8%) were low. At the time of the survey, more than 60% of women had hemoglobin level estimates ≤ 11.0 g/dl and 7.2% were Pf positive. Unmet need for contraceptives exceeded 60%. Violations of rights were widely reported: 32.1% of Karenni households reported forced labor and 10% of Karen households had been forced to move. Among Karen households, odds of anemia were 1.51 (95% confidence interval [CI] 0.95–2.40) times higher among women reporting forced displacement, and 7.47 (95% CI 2.21–25.3) higher among those exposed to food security violations. The odds of receiving no antenatal care services were 5.94 (95% CI 2.23–15.8) times higher among those forcibly displaced. Conclusions Coverage of basic maternal health interventions is woefully inadequate in these selected populations and substantially lower than even the national estimates for Burma, among the lowest in the region. Considerable political, financial, and human resources are necessary to improve access to maternal health care in these communities., Luke Mullany and colleagues examine access to essential maternal health interventions and human rights violations within vulnerable communities in eastern Burma., Editors' Summary Background. After decades of military rule, Burma has one of the world's worst health-care systems and high levels of ill health. For example, maternal mortality (deaths among women from pregnancy-related causes) is around 360 per 100,000 live births in Burma, whereas in neighboring Thailand it is only 44 per 100,000 live births. Maternal health is even worse in the Shan, Karenni, Karen and Mon states in eastern Burma where ethnic conflicts and enforced village relocations have internally displaced more than half a million people. Here, maternal mortality is thought to be about 1000 per 100, 000 live births. In an effort to improve access to life-saving maternal health interventions in these states, Burmese community-based health organizations, the Johns Hopkins Center for Public Health and Human Rights and the Global Health Access Program in the USA, and the Mae Tao Clinic (a health-worker training center in Thailand) recently set up the Mobile Obstetric Maternal Health Workers (MOM) Project. In this pilot project, local health workers from 12 communities in eastern Burma received training in antenatal care, emergency obstetrics (the care of women during childbirth), blood transfusion, and family planning at the Mae Tao Clinic. Back in Burma, these maternal health workers trained additional local health workers and traditional birth attendants. All these individuals now provide maternal health care to their communities. Why Was This Study Done? The effectiveness of the MOM project can only be evaluated if accurate baseline information on women's access to maternal health-care services is available. This information is also needed to ensure the wise use of scarce health-care resources. However, very little is known about reproductive and maternal health in eastern Burma. In this study, the researchers analyze the information on women's access to reproductive and maternal health-care services that was collected during the initial field implementation stage of the MOM project. In addition, they analyze whether exposure to enforced village relocations and other human rights violations affect access to maternal health-care services. What Did the Researchers Do and Find? Trained survey workers asked nearly 3000 ever-married women of reproductive age in the selected communities about their access to antenatal and postnatal care, skilled birth attendants, and family planning. They measured each woman's mid-upper arm circumference (an indicator of nutritional status) and tested them for anemia (iron deficiency) and infection with malaria parasites (a common cause of anemia in tropical countries). Finally, they asked the women about any recent violations of their human rights such as forced labour or relocation. Nearly 90% of the women reported a home delivery for their last baby. A skilled attendant was present at only one in 20 births and only one in three women had any antenatal care. One third of the women received postnatal care and only a third said they had access to effective contraceptives. Few women had received iron supplements or had used insecticide-treated bednets to avoid malaria-carrying mosquitos. Consequently, more than half the women were anemic and 7.2% were infected with malaria parasites. Many women also showed signs of poor nutrition. Finally, human rights violations were widely reported by the women. In Karen, the region containing most of the study communities, forced relocation tripled the risk of women developing anemia and greatly decreased their chances of receiving any antenatal care. What Do These Findings Mean? These findings show that access to maternal health-care interventions is extremely limited and that poor nutrition, anemia, and malaria, all of which increase the risk of pregnancy complications, are widespread in the communities in the MOM project. Because these communities had some basic health services and access to training in Thailand before the project started, these results probably underestimate the lack of access to maternal health-care services in eastern Burma. Nevertheless, it is clear that considerable political, financial, and human resources will be needed to improve maternal health in this region. Finally, the findings also reveal a link between human rights violations and reduced access to maternal health-care services. Thus, the scale of human rights violations will need to be considered when evaluating programs designed to improve maternal health in Burma and in other places where there is ongoing conflict. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050242. This research article is further discussed in a PLoS Medicine Perspective by Macaya Douoguih The World Health Organization provides information on all aspects of health in Burma (in several languages) The Mae Tao Clinic also provides general information about Burma and its health services More information about the MOM project is available in a previous publication by the researchers The Burma Campaign UK and Human Rights Watch both provide detailed information about human rights violations in Burma The United Nations Population Fund provides information about safe motherhood and ongoing efforts to save mothers' lives around the world

Frank Cobelens and colleagues outline key research questions that need to be addressed to maximize the impact of programmatic management of drug-resistant tuberculosis.

Background The link between poverty and health is central to the Millennium Development Goals (MDGs). Poverty can be both a cause and consequence of poor health, but there are few epidemiological studies exploring this complex relationship. The aim of this study was to examine the association between visual impairment from cataract and poverty in adults in Kenya, Bangladesh, and the Philippines. Methods and Findings A population-based case–control study was conducted in three countries during 2005–2006. Cases were persons aged 50 y or older and visually impaired due to cataract (visual acuity < 6/24 in the better eye). Controls were persons age- and sex-matched to the case participants with normal vision selected from the same cluster. Household expenditure was assessed through the collection of detailed consumption data, and asset ownership and self-rated wealth were also measured. In total, 596 cases and 535 controls were included in these analyses (Kenya 142 cases, 75 controls; Bangladesh 216 cases, 279 controls; Philippines 238 cases, 180 controls). Case participants were more likely to be in the lowest quartile of per capita expenditure (PCE) compared to controls in Kenya (odds ratio = 2.3, 95% confidence interval 0.9–5.5), Bangladesh (1.9, 1.1–3.2), and the Philippines (3.1, 1.7–5.7), and there was significant dose–response relationship across quartiles of PCE. These associations persisted after adjustment for self-rated health and social support indicators. A similar pattern was observed for the relationship between cataract visual impairment with asset ownership and self-rated wealth. There was no consistent pattern of association between PCE and level of visual impairment due to cataract, sex, or age among the three countries. Conclusions Our data show that people with visual impairment due to cataract were poorer than those with normal sight in all three low-income countries studied. The MDGs are committed to the eradication of extreme poverty and provision of health care to poor people, and this study highlights the need for increased provision of cataract surgery to poor people, as they are particularly vulnerable to visual impairment from cataract., Hannah Kuper and colleagues report a population-based case-control study conducted in three countries that found an association between poverty and visual impairment from cataract., Editors' Summary Background. Globally, about 45 million people are blind. As with many other conditions, avoidable blindness (preventable or curable blindness) is a particular problem for people in developing countries—90% of blind people live in poor regions of the world. Although various infections and disorders can cause blindness, cataract is the most common cause. In cataract, which is responsible for half of all cases of blindness in the world, the lens of the eye gradually becomes cloudy. Because the lens focuses light to produce clear, sharp images, as cataract develops, vision becomes increasingly foggy or fuzzy, colors become less intense, and the ability to see shapes against a background declines. Eventually, vision may be lost completely. Cataract can be treated with an inexpensive, simple operation in which the cloudy lens is surgically removed and an artificial lens is inserted into the eye to restore vision. In developed countries, this operation is common and easily accessible but many poor countries lack the resources to provide the operation to everyone who needs it. In addition, blind people often cannot afford to travel to the hospitals where the operation, which also may come with a fee, is done. Why Was This Study Done? Because blindness may reduce earning potential, many experts believe that poverty and blindness (and, more generally, poor health) are inextricably linked. People become ill more often in poor countries than in wealthy countries because they have insufficient food, live in substandard housing, and have limited access to health care, education, water, and sanitation. Once they are ill, their ability to earn money may be reduced, which increases their personal poverty and slows the economic development of the whole country. Because of this potential link between health and poverty, improvements in health are at the heart of the United Nations Millennium Development Goals, a set of eight goals established in 2000 with the primary aim of reducing world poverty. However, few studies have actually investigated the complex relationship between poverty and health. Here, the researchers investigate the association between visual impairment from cataract and poverty among adults living in three low-income countries. What Did the Researchers Do and Find? The researchers identified nearly 600 people aged 50 y or more with severe cataract-induced visual impairment (“cases”) primarily through a survey of the population in Kenya, Bangladesh, and the Philippines. They matched each case to a normally sighted (“control”) person of similar age and sex living nearby. They then assessed a proxy for the income level, measured as “per capita expenditure” (PCE), of all the study participants (people with cataracts and controls) by collecting information about what their households consumed. The participants' housing conditions and other assets and their self-rated wealth were also measured. In all three countries, cases were more likely to be in the lowest quarter (quartile) of the range of PCEs for that country than controls. In the Philippines, for example, people with cataract-affected vision were three times more likely than normally sighted controls to have a PCE in the lowest quartile than in the highest quartile. The risk of cataract-related visual impairment increased as PCE decreased in all three countries. Similarly, severe cataract-induced visual impairment was more common in those who owned fewer assets and those with lower self-rated wealth. However, there was no consistent association between PCE and the level of cataract-induced visual impairment. What Do These Findings Mean? These findings show that there is an association between visual impairment caused by cataract and poverty in Kenya, Bangladesh, and the Philippines. However, because the financial circumstances of the people in this study were assessed after cataracts had impaired their sight, this study does not prove that poverty is a cause of visual impairment. A causal connection between poverty and cataract can only be shown by determining the PCEs of normally sighted people and following them for several years to see who develops cataract. Nevertheless, by confirming an association between poverty and blindness, these findings highlight the need for increased provision of cataract surgery to poor people, particularly since cataract surgery has the potential to improve the quality of life for many people in developing countries at a relatively low cost. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050244. This study is further discussed in a PLoS Medicine Perspective by Susan Lewallen The MedlinePlus encyclopedia contains a page on cataract, and MedlinePlus also provides a list of links to further information about cataract (in English and Spanish) VISION 2020, a global initiative for the elimination of avoidable blindness launched by the World Health Organization and the International Agency for the Prevention of Blindness, provides information in several languages about many causes of blindness, including cataract. It also has an article available for download on blindness, poverty, and development Information is available from the World Health Organization on health and the Millennium Development Goals (in English, French, and Spanish) The International Centre for Eye Health carries out research and education activities to improve eye health and eliminate avoidable blindness with a focus on populations with low incomes

Nearly 30 years after the first cases of AIDS were reported [1] and HIV identified as the causative agent, Africa today bears a disproportionate burden of the disease. Sub-Saharan Africa has just over 10% of the world's population but is home to more than 65% of the 33 million people in the world estimated to be living with HIV/AIDS. The annual rate of new infections continues to rise, with an estimated 2.5 million people newly infected in 2007 [2]. Although newer initiatives aimed at providing universal access to antiretroviral therapy in Africa are ongoing, most Africans receive neither treatment nor adequate care [3]. Relatively few HIV-infected patients in sub-Saharan Africa (about 1 million) are currently receiving antiretroviral treatment [4], and many more new cases are occurring each year [2]. It is thus evident that treatment alone will not control the spread of the disease and that a vaccine is our best hope of halting this pandemic. In the history of infectious diseases, effective vaccines are critical public health tools to control and prevent diseases. Developing an effective HIV vaccine is proving to be one of the greatest challenges in biomedical research. The need for a simple, safe, effective, affordable, and equitably distributed preventive HIV vaccine to complement existing HIV/AIDS prevention, treatment, and care programs is greater than ever. It is probable that vaccines will form part of future innovative interventions including microbicides and circumcision, used in conjunction with other more traditional prevention interventions. Summary Points The AIDS pandemic continues to be the most serious public health challenge facing the world today, and Africa bears an overwhelming proportion of infections, with unprecedented medical and socioeconomic consequences. The best hope to end the AIDS pandemic remains the development of an effective HIV vaccine, and its distribution to all communities. The African AIDS Vaccine Programme (AAVP), formed in 2000, is a network of African HIV vaccine stakeholders, led by Africans across the continent, with a vision of an African continent without AIDS. AAVP supports and represents the diverse African communities involved in HIV vaccine research and development (R&D), and is an important unified voice for African stakeholders. This paper describes what AAVP is, what it does, and its impact, successes, and challenges. Finally, we discuss where AAVP is heading to harmonize with the Global HIV Vaccine Enterprise and the dynamic HIV vaccine research field.

Colin Sutherland discusses a Policy Forum article that explores the design and standardization of pre-licensure phase III antimalarial treatment trials.

Background Envenoming resulting from snakebites is an important public health problem in many tropical and subtropical countries. Few attempts have been made to quantify the burden, and recent estimates all suffer from the lack of an objective and reproducible methodology. In an attempt to provide an accurate, up-to-date estimate of the scale of the global problem, we developed a new method to estimate the disease burden due to snakebites. Methods and Findings The global estimates were based on regional estimates that were, in turn, derived from data available for countries within a defined region. Three main strategies were used to obtain primary data: electronic searching for publications on snakebite, extraction of relevant country-specific mortality data from databases maintained by United Nations organizations, and identification of grey literature by discussion with key informants. Countries were grouped into 21 distinct geographic regions that are as epidemiologically homogenous as possible, in line with the Global Burden of Disease 2005 study (Global Burden Project of the World Bank). Incidence rates for envenoming were extracted from publications and used to estimate the number of envenomings for individual countries; if no data were available for a particular country, the lowest incidence rate within a neighbouring country was used. Where death registration data were reliable, reported deaths from snakebite were used; in other countries, deaths were estimated on the basis of observed mortality rates and the at-risk population. We estimate that, globally, at least 421,000 envenomings and 20,000 deaths occur each year due to snakebite. These figures may be as high as 1,841,000 envenomings and 94,000 deaths. Based on the fact that envenoming occurs in about one in every four snakebites, between 1.2 million and 5.5 million snakebites could occur annually. Conclusions Snakebites cause considerable morbidity and mortality worldwide. The highest burden exists in South Asia, Southeast Asia, and sub-Saharan Africa., Janaka de Silva and colleagues estimate that globally at least 421,000 envenomings and 20,000 deaths occur each year due to snakebite., Editors' Summary Background. Of the 3,000 or so snake species that exist in the world, about 600 are venomous. Venomous snakes—which exist on every continent except Antarctica—immobilize their prey by injecting modified saliva (venom) that contains toxins into their prey's tissues through their fangs—specialized, hollow teeth. Snakes also use their venoms for self defense and will bite people who threaten, startle or provoke them. Snakebites caused by the families Viperidae (for example, pit vipers) and Elapidae (for example, kraits and cobras) are particularly dangerous to people. The potentially fatal effects of being “envenomed” (having venom injected) by these snakes include widespread bleeding, muscle paralysis, and tissue destruction (necrosis) around the bite site. Bites from these snakes can also cause permanent disability. For example, snakebite victims, who tend to be young and male, may have to have a limb amputated because of necrosis. The best treatment for any snakebite is to get the victim to a hospital as soon as possible where antivenoms (mixtures of antibodies that neutralize venoms) can be given. Why Was This Study Done? Although snakebites occur throughout the world, envenoming snakebites are thought to pose a particularly important yet largely neglected threat to public health. This is especially true in rural areas of tropical and subtropical countries where snakebites are common but where there is limited access to health care and to antivenoms. The true magnitude of the public-health threat posed by snakebites in these countries (and elsewhere in the world) is unknown, which makes it hard for public-health officials to optimize the prevention and treatment of snakebites in their respective countries. In this study, therefore, the researchers develop and apply a new method to estimate the global burden of snakebite. What Did the Researchers Do and Find? The researchers systematically searched the scientific literature for publications on snakebites and deaths from snakebites and extracted data on snakebite deaths in individual countries from the World Health Organization (WHO) mortality database. They also contacted Ministries of Health, National Poison Centers, and snakebite experts for unpublished information (“grey” literature) on snakebites. Together, these three approaches provided data on the number of snakebite envenomings and deaths for 135 and 162 countries, respectively. The researchers then grouped the 227 countries of the world into 21 geographical regions, each of which contained countries with similar population characteristics, and used the results of studies done in individual countries within each region to estimate the numbers of snakebite envenomings and deaths for each region. Finally, they added up these estimates to obtain an estimate of the global burden of snakebite. Using this method, the researchers estimate that, worldwide, at least 421,000 envenomings and 20,000 deaths from snakebite occur every year; the actual numbers, they suggest, could be as high as 1.8 million envenomings and 94,000 deaths. Their estimates also indicate that the highest burden of snakebite envenomings and death occurs in South and Southeast Asia and in sub-Saharan Africa, and that India is the country with the highest annual number of envenomings (81,000) and deaths (nearly 11,000). What Do These Findings Mean? These findings indicate that snakebites cause considerable illness and death around the world. Because of the careful methods used by the researchers, their global estimates of snakebite envenomings and deaths are probably more accurate than previous estimates. However, because the researchers had to make many assumptions in their calculations and because there are so few reliable data on the numbers of snakebites and deaths from the rural tropics, the true regional and global numbers of these events may differ substantially from the estimates presented here. In particular, the regional estimates for eastern sub-Saharan Africa, a region where snakebites are very common and where antivenoms are particularly hard to obtain, are likely to be inaccurate because they are based on a single study. The researchers, therefore, call for more studies on snakebite envenoming and deaths to be done to provide the information needed to deal effectively with this neglected public-health problem. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050218. This study is further discussed in a PLoS Medicine Perspective by Chippaux The MedlinePlus Medical Encyclopedia has a page on snakebites (in English and Spanish) The UK National Health Service Direct health encyclopedia has detailed information about all aspects of snakebites Wikipedia has pages on venomous snakes and on snakebites (note: Wikipedia is a free online encyclopedia that anyone can edit; available in several languages) The World Health Organization provides information about antivenoms and about efforts to increase access to antivenoms in developing countries (available in several languages) A previous article in PLoS Medicine also discusses the neglected problem of snakebite envenoming: Gutiérrez JM, Theakston RDG, Warrell DA (2006) Confronting the Neglected Problem of Snake Bite Envenoming: The Need for a Global Partnership. PLoS Med 3(6): e150

Background Transmission of dengue viruses (DENV), the leading cause of arboviral disease worldwide, is known to vary through time and space, likely owing to a combination of factors related to the human host, virus, mosquito vector, and environment. An improved understanding of variation in transmission patterns is fundamental to conducting surveillance and implementing disease prevention strategies. To test the hypothesis that DENV transmission is spatially and temporally focal, we compared geographic and temporal characteristics within Thai villages where DENV are and are not being actively transmitted. Methods and Findings Cluster investigations were conducted within 100 m of homes where febrile index children with (positive clusters) and without (negative clusters) acute dengue lived during two seasons of peak DENV transmission. Data on human infection and mosquito infection/density were examined to precisely (1) define the spatial and temporal dimensions of DENV transmission, (2) correlate these factors with variation in DENV transmission, and (3) determine the burden of inapparent and symptomatic infections. Among 556 village children enrolled as neighbors of 12 dengue-positive and 22 dengue-negative index cases, all 27 DENV infections (4.9% of enrollees) occurred in positive clusters (p < 0.01; attributable risk [AR] = 10.4 per 100; 95% confidence interval 1–19.8 per 100]. In positive clusters, 12.4% of enrollees became infected in a 15-d period and DENV infections were aggregated centrally near homes of index cases. As only 1 of 217 pairs of serologic specimens tested in positive clusters revealed a recent DENV infection that occurred prior to cluster initiation, we attribute the observed DENV transmission subsequent to cluster investigation to recent DENV transmission activity. Of the 1,022 female adult Ae. aegypti collected, all eight (0.8%) dengue-infected mosquitoes came from houses in positive clusters; none from control clusters or schools. Distinguishing features between positive and negative clusters were greater availability of piped water in negative clusters (p < 0.01) and greater number of Ae. aegypti pupae per person in positive clusters (p = 0.04). During primarily DENV-4 transmission seasons, the ratio of inapparent to symptomatic infections was nearly 1:1 among child enrollees. Study limitations included inability to sample all children and mosquitoes within each cluster and our reliance on serologic rather than virologic evidence of interval infections in enrollees given restrictions on the frequency of blood collections in children. Conclusions Our data reveal the remarkably focal nature of DENV transmission within a hyperendemic rural area of Thailand. These data suggest that active school-based dengue case detection prompting local spraying could contain recent virus introductions and reduce the longitudinal risk of virus spread within rural areas. Our results should prompt future cluster studies to explore how host immune and behavioral aspects may impact DENV transmission and prevention strategies. Cluster methodology could serve as a useful research tool for investigation of other temporally and spatially clustered infectious diseases.

Background to the debate: The global burden of disease falls disproportionately upon the world's low-income countries, which are often struggling with weak health systems. Both the public and private sector deliver health care in these countries, but the appropriate role for each of these sectors in health system strengthening remains controversial. This debate examines whether the private sector should step up its involvement in the health systems of low-income countries., This Debate examines whether the private sector should step up its involvement in the health systems of low-income countries.

Envenoming resulting from snakebites is an important public health problem in many tropical and subtropical countries. Few attempts have been made to quantify the burden, and recent estimates all suffer from the lack of an objective and reproducible methodology. In an attempt to provide an accurate, up-to-date estimate of the scale of the global problem, we developed a new method to estimate the disease burden due to snakebites.The global estimates were based on regional estimates that were, in turn, derived from data available for countries within a defined region. Three main strategies were used to obtain primary data: electronic searching for publications on snakebite, extraction of relevant country-specific mortality data from databases maintained by United Nations organizations, and identification of grey literature by discussion with key informants. Countries were grouped into 21 distinct geographic regions that are as epidemiologically homogenous as possible, in line with the Global Burden of Disease 2005 study (Global Burden Project of the World Bank). Incidence rates for envenoming were extracted from publications and used to estimate the number of envenomings for individual countries; if no data were available for a particular country, the lowest incidence rate within a neighbouring country was used. Where death registration data were reliable, reported deaths from snakebite were used; in other countries, deaths were estimated on the basis of observed mortality rates and the at-risk population. We estimate that, globally, at least 421,000 envenomings and 20,000 deaths occur each year due to snakebite. These figures may be as high as 1,841,000 envenomings and 94,000 deaths. Based on the fact that envenoming occurs in about one in every four snakebites, between 1.2 million and 5.5 million snakebites could occur annually.Snakebites cause considerable morbidity and mortality worldwide. The highest burden exists in South Asia, Southeast Asia, and sub-Saharan Africa.

Correction for: Wagstaff SC, Laing GD, Theakston RDG, Papaspyridis C, Harrison RA (2006) Bioinformatics and multiepitope DNA immunization to design rational snake antivenom. PLoS Med 3(6): e184. doi:10.1371/journal.pmed.0030184 In the Supporting Information section of this paper, Figure S1 and Figure S2 were incorrectly linked. Figure S1 and Figure S2 labeled and in the order originally intended are provided here.

Jean-Paul Guthmann and colleagues describe the output of MSF's work in antimalarial efficacy assessment during the last decade.

Background Rotavirus, predominantly of group A, is a major cause of severe diarrhoea worldwide, with the greatest burden falling on young children living in less-developed countries. Vaccines directed against this virus have shown promise in recent trials, and are undergoing effectiveness evaluation in sub-Saharan Africa. In this region limited childhood data are available on the incidence and clinical characteristics of severe group A rotavirus disease. Advocacy for vaccine intervention and interpretation of effectiveness following implementation will benefit from accurate base-line estimates of the incidence and severity of rotavirus paediatric admissions in relevant populations. The study objective was to accurately define the incidence and severity of group A rotavirus disease in a resource-poor setting necessary to make informed decisions on the need for vaccine prevention. Methods and Findings Between 2002 and 2004 we conducted prospective surveillance for group A rotavirus infection at Kilifi District Hospital in coastal Kenya. Children < 13 y of age were eligible as “cases” if admitted with diarrhoea, and “controls” if admitted without diarrhoea. We calculated the incidence of hospital admission with group A rotavirus using data from a demographic surveillance study of 220,000 people in Kilifi District. Of 15,347 childhood admissions 3,296 (22%) had diarrhoea, 2,039 were tested for group A rotavirus antigen and, of these, 588 (29%) were positive. 372 (63%) rotavirus-positive cases were infants. Of 620 controls 19 (3.1%, 95% confidence interval [CI] 1.9–4.7) were rotavirus positive. The annual incidence (per 100,000 children) of rotavirus-positive admissions was 1,431 (95% CI 1,275–1,600) in infants and 478 (437–521) in under-5-y-olds, and highest proximal to the hospital. Compared to children with rotavirus-negative diarrhoea, rotavirus-positive cases were less likely to have coexisting illnesses and more likely to have acidosis (46% versus 17%) and severe electrolyte imbalance except hyponatraemia. In-hospital case fatality was 2% among rotavirus-positive and 9% among rotavirus-negative children. Conclusions In Kilifi > 2% of children are admitted to hospital with group A rotavirus diarrhoea in the first 5 y of life. This translates into over 28,000 vaccine-preventable hospitalisations per year across Kenya, and is likely to be a considerable underestimate. Group A rotavirus diarrhoea is associated with acute life-threatening metabolic derangement in otherwise healthy children. Although mortality is low in this clinical research setting this may not be generally true in African hospitals lacking rapid and appropriate management., Combining prospective hospital-based surveillance with demographic data in Kilifi, Kenya, James Nokes and colleagues assess the burden of rotavirus diarrhea in young children., Editors' Summary Background. Rotavirus is a leading global cause of diarrhea in babies and young children. Indeed, most children become infected at least once with this virus before their fifth birthday. Rotavirus is usually spread by children or their caregivers failing to wash their hands properly after going to the toilet and then contaminating food or drink. The symptoms of rotavirus infection—diarrhea, vomiting, and fever—are usually mild, but if the diarrhea is severe it can quickly lead to dehydration. Mild to moderate dehydration can be treated at home by providing the patient with plenty of fluids or with a special rehydration drink that replaces lost water and salts. However, for infants or toddlers who become severely dehydrated, rehydration with intravenous fluids (fluids injected directly into a vein) in hospital may be essential. Unfortunately, in developing countries in sub-Saharan Africa and elsewhere, this treatment is not widely available and every year more than half a million young children die from rotavirus infections. Why Was This Study Done? Two rotavirus vaccines that could reduce this burden of disease are currently undergoing clinical trials to determine their effectiveness in sub-Saharan Africa. However, very little is known about the incidence of severe rotavirus infections among children living in this region (that is, how many children develop severe disease every year) or about the clinical characteristics of the disease here. Public-health officials need this baseline information before they can make informed decisions about the mass introduction of rotavirus vaccination and to help them judge whether the intervention has been successful if it is introduced. In this study, the researchers examine the incidence and clinical characteristics of rotavirus infections (specifically, group A rotavirus [GARV] infections; there are several different rotaviruses but GARV causes most human infections) among children admitted to the district hospital in Kilifi, Kenya. What Did the Researchers Do and Find? During the 3-year study, more than 15,000 children under the age of 13 years were admitted to Kilifi District Hospital, a little under a quarter of whom had severe diarrhea. Nearly a third of the patients admitted with diarrhea who were tested had a GARV-specific protein in their stools (faeces); by contrast, only three in 100 children admitted without diarrhea showed any evidence of GARV infection. Two-thirds of the GARV-positive children were infants (under 1 year old). Using these figures and health surveillance data (records of births, deaths, and causes of death) collected in the area around the hospital, the researchers calculated that the annual incidence (per 100,000 children) of GARV-positive hospital admissions in the region was 1,431 for infants and 478 for children under age 5 years. Children with GARV-positive diarrhea were less likely to have other illnesses (for example, malnutrition) than those admitted with GARV-negative diarrhea, the researchers report, but were more likely to have life-threatening complications such as severe dehydration and salt imbalances in their blood. However, despite being more ill on admission, only 1 in 50 children with GARV-positive diarrhea died, compared to nearly 1 in 10 of the children with GARV-negative diarrhea; the GARV-positive children also left hospital quicker than those who were GARV-negative. What Do These Findings Mean? These findings indicate that severe GARV-positive diarrhea is a major cause of hospital admission among otherwise healthy young children in the Kilifi region of Kenya. By the time they are 5 years old, the researchers estimate that 1 in 50 of the children living in this region will have been admitted to hospital with severe GARV-positive diarrhea. Because rotavirus vaccines prevent virtually all severe rotavirus-associated disease (at least in developed countries where their effectiveness has been extensively tested), the researchers estimate that vaccination might prevent more than 28,000 hospitalizations annually across Kenya; however, this prediction assumes that it is valid to extrapolate from the data obtained from this one district hospital to the entire country. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050153. The US Centers for Disease Control and Prevention provides information about rotavirus infections, surveillance, and vaccination (in English and Spanish) The UK National Health Service Direct health encyclopedia provides information on rotavirus infections MedlinePlus also provides links to information on rotavirus (in English and Spanish) The African Rotavirus Surveillance Network is working to improve knowledge about rotavirus infections in Africa The Rotavirus Vaccine Program aims to reduce child illness and death from diarrhea by increasing the availability of rotavirus vaccines in developing countries (in English and Spanish) PATH, a nonprofit international organization that aims to create sustainable, culturally relevant solutions to global health problems, also provides detailed information on rotavirus surveillance and disease burden

Background The international financing of malaria control has increased significantly in the last ten years in parallel with calls to halve the malaria burden by the year 2015. The allocation of funds to countries should reflect the size of the populations at risk of infection, disease, and death. To examine this relationship, we compare an audit of international commitments with an objective assessment of national need: the population at risk of stable Plasmodium falciparum malaria transmission in 2007. Methods and Findings The national distributions of populations at risk of stable P. falciparum transmission were projected to the year 2007 for each of 87 P. falciparum–endemic countries. Systematic online- and literature-based searches were conducted to audit the international funding commitments made for malaria control by major donors between 2002 and 2007. These figures were used to generate annual malaria funding allocation (in US dollars) per capita population at risk of stable P. falciparum in 2007. Almost US$1 billion are distributed each year to the 1.4 billion people exposed to stable P. falciparum malaria risk. This is less than US$1 per person at risk per year. Forty percent of this total comes from the Global Fund to Fight AIDS, Tuberculosis and Malaria. Substantial regional and national variations in disbursements exist. While the distribution of funds is found to be broadly appropriate, specific high population density countries receive disproportionately less support to scale up malaria control. Additionally, an inadequacy of current financial commitments by the international community was found: under-funding could be from 50% to 450%, depending on which global assessment of the cost required to scale up malaria control is adopted. Conclusions Without further increases in funding and appropriate targeting of global malaria control investment it is unlikely that international goals to halve disease burdens by 2015 will be achieved. Moreover, the additional financing requirements to move from malaria control to malaria elimination have not yet been considered by the scientific or international community., To reach global malaria control goals, Robert Snow and colleagues argue that more international funding is needed but that it must be targeted at specific countries most at risk., Editors' Summary Background. Malaria is one of the most common infectious diseases in the world and one of the greatest global public health problems. The Plasmodium falciparum parasite causes approximately 500 million cases each year and over one million deaths. More than 40% of the world's population is at risk of malaria. The Millennium Development Goals (MDGs), established by the United Nations in 2000, include a target in Goal 6: “to have halted by 2015 and begun to reverse the incidence of malaria and other major diseases.” Following the launch of the MDG and international initiatives like Roll Back Malaria, there has been an upsurge in support for malaria control. This effort has included the formation of the Global Fund to Fight AIDS, Tuberculosis and Malaria (GFATM) and considerable funding from the US President's Malaria Initiative, the World Bank, the UK Department for International Development, USAID, and nongovernmental agencies and foundations like the Bill & Melinda Gates Foundation. But it is not yet clear how equitable or effective the financial commitments to malaria control have been. Why Was This Study Done? As part of the activities of the Malaria Atlas Project, the researchers had previously generated a global map of the limits of P. falciparum transmission. This map detailed areas where risk is moderate or high (stable transmission areas where malaria is endemic) and areas where the risk of transmission is low (unstable transmission areas where sporadic outbreaks of malaria may occur). Because the level of funding to control malaria should be proportionate to the size of the populations at risk, the researchers in this study appraised whether the areas of greatest need were receiving financial resources in proportion to this risk. That is, whether there is equity in how malaria funding is allocated. What Did the Researchers Do and Find? To assess the international financing of malaria control, the researchers conducted a audit of financial commitments to malaria control of the GFATM, national governments, and other donors for the period 2002 to 2007. To assess need, they estimated the population at risk of stable P. falciparum malaria transmission in 2007, building on their previous malaria map. Financial commitments were identified via online and literature searches, including the GFATM Web site, the World Malaria Report produced by WHO and UNICEF, and various other sources of financial information. Together these data allowed the authors to generate an estimate of the annual malaria funding allocation per capita population at risk of P. falciparum. Of the 87 malaria-endemic countries, 76 received malaria funding commitments by the end of 2007. Overall, annual funding amounted to US$1 billion dollars, or less than US$1 per person at risk. Forty percent came from the GFATM, and the remaining from a mix of national government and external donors. The authors found great regional variation in the levels of funding. For example, looking at just the countries approved for GFATM funding, Myanmar was awarded an average annual per capita-at-risk amount of US$0.01 while Suriname was awarded US$147. With all financial commitments combined, ten countries had per capita annual support of more than US$4 per person, but 34 countries had less than US$1, including 16 where annual malaria support was less than US$0.5 per capita. These 16 countries represent 50% of the global population at risk and include seven of the poorest countries in Africa and two of the most densely populated stable endemic countries in the world (India and Indonesia). What Do These Findings Mean? The researchers find that the distribution of funds across the regions affected by malaria to be generally appropriate, with the Africa region and low-population-at-risk areas such as the Americas, the Caribbean, the Middle East, and Eastern Europe receiving proportionate annual malaria support. But they also identify large shortfalls, such as in the South East Asia and Western Pacific regions, which represents 47% of the global population at risk but received only 17% of GFATM and 24% of non-GFATM support. National government spending also falls short: for example, in Nigeria, where more than 100 million people are at risk of stable P. falciparum transmission, less than US$1 is invested per person per year. These findings illustrate how important it is to examine financial commitments against actual needs. Given the gaps between funding support and level of stable P. falciparum risk, the authors conclude that the goal to reduce the global burden of malaria by 2015 very likely will not be met with current commitments. They estimate that there remains a 50%–450% shortfall in funding needed to scale up malaria control worldwide. Future research should assess the impact of these funding commitments and what additional resources will be needed if goals of malaria elimination are added to malaria control targets. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050142. This study is discussed further in a PLoS Medicine Perspective by Anthony Kiszewski The authors of this article have also published a global map of malaria risk; see Guerra, et al. (2008) PLoS Med 5(2) e38 Information is available from the Global Fund to Fight AIDS, Tuberculosis and Malaria More information is available on global mapping of malaria risk from the Malaria Atlas Project

There is great excitement in the tuberculosis (TB) scientific community over the introduction of new tools into TB control activities. The development of new tools is an important component of the Global Plan to Stop TB and the World Health Organization's new global Stop TB Strategy [1,2]. Anticipating the introduction of new tools, the Stop TB Partnership has established a Retooling Task Force to develop a framework for engaging policy makers to foster accelerated adoption and implementation of new tools into TB control programs [3].

ThePLoS Medicine Editors argue that the current business model of the pharmaceutical industry provides no incentives for the development of new treatments for maternal health, and that political will is needed to support new approaches.

Background Rates of diseases and injuries and the effects of their risk factors can have substantial subnational heterogeneity, especially in middle-income countries like Mexico. Subnational analysis of the burden of diseases, injuries, and risk factors can improve characterization of the epidemiological transition and identify policy priorities. Methods and Findings We estimated deaths and loss of healthy life years (measured in disability-adjusted life years [DALYs]) in 2004 from a comprehensive list of diseases and injuries, and 16 major risk factors, by sex and age for Mexico and its states. Data sources included the vital statistics, national censuses, health examination surveys, and published epidemiological studies. Mortality statistics were adjusted for underreporting, misreporting of age at death, and for misclassification and incomparability of cause-of-death assignment. Nationally, noncommunicable diseases caused 75% of total deaths and 68% of total DALYs, with another 14% of deaths and 18% of DALYs caused by undernutrition and communicable, maternal, and perinatal diseases. The leading causes of death were ischemic heart disease, diabetes mellitus, cerebrovascular disease, liver cirrhosis, and road traffic injuries. High body mass index, high blood glucose, and alcohol use were the leading risk factors for disease burden, causing 5.1%, 5.0%, and 7.3% of total burden of disease, respectively. Mexico City had the lowest mortality rates (4.2 per 1,000) and the Southern region the highest (5.0 per 1,000); under-five mortality in the Southern region was nearly twice that of Mexico City. In the Southern region undernutrition and communicable, maternal, and perinatal diseases caused 23% of DALYs; in Chiapas, they caused 29% of DALYs. At the same time, the absolute rates of noncommunicable disease and injury burdens were highest in the Southern region (105 DALYs per 1,000 population versus 97 nationally for noncommunicable diseases; 22 versus 19 for injuries). Conclusions Mexico is at an advanced stage in the epidemiologic transition, with the majority of the disease and injury burden from noncommunicable diseases. A unique characteristic of the epidemiological transition in Mexico is that overweight and obesity, high blood glucose, and alcohol use are responsible for larger burden of disease than other noncommunicable disease risks such as tobacco smoking. The Southern region is least advanced in the epidemiological transition and suffers from the largest burden of ill health in all disease and injury groups., Gretchen Stevens and colleagues estimate deaths and loss of healthy life years (measured in disability-adjusted life years, DALYs) for Mexico as a whole and its 32 states., Editors' Summary Background. The impact that a particular disease has upon a population is known as the “burden of disease.” This burden is estimated by considering how many deaths the disease causes and how much it disables those still living. The relative contributions of different diseases and injuries to the loss of healthy life from death and disability vary greatly among countries. Broadly speaking, in low-income countries (such as many African countries), infectious diseases and undernutrition are the major causes of ill health and death whereas in high-income countries (for example, the United States), noncommunicable diseases such as heart disease, diabetes, and stroke are more important. As poor countries become richer, they experience a change in the pattern of disease away from infectious diseases and malnutrition and toward noncommunicable diseases. Health experts call this change the “epidemiological transition” (epidemiology is the study of the distribution and causes of diseases in populations). Governments need to know as much as possible about which diseases have the greatest burden—and about where the country is in the epidemiological transition—to help them implement effective health policies. For example, there is no point in setting up treatment centers for a specific infectious disease in a country where the disease no longer occurs. Equally importantly, governments need to know which lifestyle choices and other genetic and environmental factors affect the chances of people in their country developing specific diseases so that they can provide relevant educational and intervention programs. Why Was This Study Done? Most analyses of the burden of disease have been done at the national and global scale. However, in middle-income countries, different regions of the country may be at different stages of the epidemiological transition and may, therefore, have very different patterns of disease. In this study, the researchers investigate whether this is the case for Mexico, a middle-income country that has developed rapidly over the past few decades. Mexico recently reformed its health system to improve access to health care for the poor and underserved. Under this new system, individual states play an important role in allocating health-care resources (as they do in many other countries) so it is very important to know how the burden of disease varies in different states of the country. What Did the Researchers Do and Find? The researchers estimated deaths and loss of healthy life years caused by various diseases and injuries for Mexico and its states using data from death registers, censuses, health examination surveys, and epidemiological studies. Loss of healthy life years was measured using a metric called “disability-adjusted life years” (DALYs)—one DALY is equivalent to the loss of one year of healthy life because of premature death or disability. They also identified the major risk factors for these diseases and injuries across the country. Nationally, noncommunicable diseases (particularly heart disease, diabetes, stroke, and liver cirrhosis) caused 75% of deaths and 68% of DALYs. Undernutrition, infectious diseases, and problems occurring in mothers and infants around the time of birth (maternal and perinatal diseases) caused 14% of deaths and 18% of DALYs. The leading risk factors for disease in Mexico were being overweight, having high blood glucose, and alcohol use. When the researchers studied different regions of the country, they found that Mexico City had the lowest death rate whereas the relatively undeveloped Southern region of Mexico had the highest, particularly among young children. In Chiapas, the most southerly state of Mexico, undernutrition and infectious, maternal, and perinatal diseases caused nearly a third of DALYs. In addition to the highest infectious disease burden, the Southern region also had the highest noncommunicable disease and injury burden per head of population. What Do These Findings Mean? These findings indicate that Mexico as a nation is at an advanced stage of the epidemiological transition. In other words, because of the improvement in its economic status, the burden of disease caused by infectious diseases and undernutrition has decreased, and noncommunicable diseases now cause the largest share of the total burden of disease. However, the study also shows that the poorest regions of the country, which have the highest overall burden of disease, are lagging behind the richer regions in terms of their position in the epidemiological transition. Thus different health priorities need to be set in different regions of Mexico (and in other middle-income countries where the burden of disease is also likely to vary with region). Finally, the information provided by this study about the forces driving the epidemiological transition in Mexico, such as the importance of obesity and alcohol use, should help public-health officials decide how to improve the overall health of the Mexican population. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050125. A related PLoS Medicine Perspective by Martin Tobias further discusses this research The World Health Organization provides information on the Global Burden of Disease Project including links to other burden of disease resources. It also provides detailed information on various aspects of health in Mexico (in several languages), and an explanation of DALYs Read a detailed article on the “epidemiological transition” by Abdel Omran, who proposed this idea in 1971 A large amount of Mexican data is available online for Spanish speakers. Complete raw mortality statistics can be found on the Mexican Ministry of Health's Web site http://sinais.salud.gob.mx/sinais.php. Also online is the complete report of the ENSANUT survey (Encuesta Nacional de Salud y Nutrición 2006) http://www.insp.mx/ensanut/, which was one of the major data sources used to determine risk factor exposure

In sub-Saharan Africa management standards for NCDs in public health services are poor. With the growing burden of NCDs now is the time to develop and implement standardised NCD management protocols and systems for diagnosis treatment monitoring and reporting. DOTS has been the framework for tuberculosis control for over a decade allowing structured and well monitored services to be delivered to millions of tuberculosis patients in some of the poorest countries of the world. The DOTS model has been successfully adapted for the scale-up of ART in Malawi allowing long-term structured treatment to be given to thousands of patients. This paper discusses why the DOTS paradigm should be adapted for NCDs and with the "DOTS five-point policy package" as a template shows how this could be implemented and rolled out in resource-poor countries with special reference to sub-Saharan Africa. (excerpt)

Currently in sub-Saharan Africa, most patients with surgical problems that are routinely treatable in high-income countries never reach a health facility, or are treated at a facility with inadequate human or physical resources. These conditions lead to premature death or physical disability with a significant economic burden. Meanwhile, the last decade has seen the emergence of numerous “neglected tropical disease” (NTD) initiatives in global public health. As surgeons working with clinicians in sub-Saharan Africa, the momentum for NTDs causes us to ask: Shouldn't surgical conditions also be considered “neglected”? This article compares NTDs and surgical conditions in sub-Saharan Africa, considering their estimated burden and the cost-effectiveness of treatment, the scope of these conditions and associated global health disparities, and the effect of donor priorities on provision of surgical services. Lessons from NTD initiatives are analyzed among possible solutions to improving access to surgical services in sub-Saharan Africa.

Background Severe malaria (SM) is classically associated with Plasmodium falciparum infection. Little information is available on the contribution of P. vivax to severe disease. There are some epidemiological indications that P. vivax or mixed infections protect against complications and deaths. A large morbidity surveillance conducted in an area where the four species coexist allowed us to estimate rates of SM among patients infected with one or several species. Methods and Findings This was a prospective cohort study conducted within the framework of the Malaria Vaccine Epidemiology and Evaluation Project. All presumptive malaria cases presenting at two rural health facilities over an 8-y period were investigated with history taking, clinical examination, and laboratory assessment. Case definition of SM was based on the World Health Organization (WHO) criteria adapted for the setting (i.e., clinical diagnosis of malaria associated with asexual blood stage parasitaemia and recent history of fits, or coma, or respiratory distress, or anaemia [haemoglobin < 5 g/dl]). Out of 17,201 presumptive malaria cases, 9,537 (55%) had a confirmed Plasmodium parasitaemia. Among those, 6.2% (95% confidence interval [CI] 5.7%–6.8%) fulfilled the case definition of SM, most of them in children, In a study carried out in Papua New Guinea, Blaise Genton and colleagues show thatPlasmodium vivax is associated with severe malaria., Editors' Summary Background. Malaria is a parasitic infection that is transmitted to people by infected mosquitoes. Four different parasites cause malaria—Plasmodium falciparum, P. vivax, P. ovale, and P. malariae. Of these, P. vivax is the commonest and most widely distributed, whereas P. falciparum causes the most deaths. All these parasites enter their human host when an infected mosquito takes a blood meal. They then migrate to the liver where they replicate without causing any symptoms. Eight to nine days later, mature parasites are released from the liver cells and invade red blood cells. Here, they multiply rapidly before bursting out and infecting more red blood cells. The recurring flu-like symptoms of malaria are caused by this cyclical increase in parasitemia (parasites in the blood) and should be treated promptly with antimalarial drugs to prevent the development of potentially fatal complications. Infections with P. falciparum in particular can cause anemia by destroying the red blood cells and can damage vital organs (including the brain) by blocking the capillaries that supply them with blood. Why Was This Study Done? It is generally believed that P. vivax malaria is rarely fatal. There is even some evidence that infection with P. vivax alone (monoinfection) or with other malaria parasites (mixed infection) provides protection against malarial complications. Recently, however, there have been reports of severe disease and deaths associated with infection by P. vivax alone. Most of these reports do not indicate what proportion of severe malaria cases are caused by P. vivax infections, but if P. vivax is responsible for a significant proportion of malarial deaths, efforts to prevent these deaths will need to target P. vivax as well as P. falciparum. In this study, therefore, the researchers estimate the proportion of cases of severe malaria among patients infected with one or several Plasmodium species in Papua New Guinea, a country where all four species coexist. What Did the Researchers Do and Find? The researchers enrolled everyone attending two rural health facilities in the Wosera subdistrict of Papua New Guinea over an eight-year period with symptoms indicative of malaria but without symptoms of any other disease (presumptive malaria cases) into their prospective cohort study. They asked each patient about their symptoms, did a standard physical examination, looked for parasites in their blood, and measured their hemoglobin levels to see whether they were anemic. Out of 17,201 presumptive malaria cases, 483 had severe malaria (defined as parasitemia plus a recent history of fits, coma, breathing problems, or anemia). Most of the patients with severe malaria were less than five years old—children have little immunity to Plasmodium parasites. In this age group, 11.7% of patients infected with P. falciparum, 8.8% of patients infected with P. vivax, and 17.3% of patients infected with both parasites had severe malaria. Patients with severe malaria caused by P. vivax presented with breathing difficulties more often than those infected with P. falciparum, whereas anemia was more common among patients with severe malaria caused by P. falciparum than by P. vivax. What Do These Findings Mean? The researchers use these results and data on the numbers of infections with each parasite to calculate that, in this rural region of Papua New Guinea, P. vivax is responsible for one-fifth of severe malaria cases, P. falciparum is responsible for three-quarters of cases, and the rest involve mixed P. falciparum/P. vivax infections. Put another way, these findings suggest that about one in ten children under the age of five years infected with either P. vivax or P. falciparum may develop severe malaria. These findings provide no evidence, however, that mixed infections are protective. Because the diagnosis of severe malaria was not confirmed by outcome data (deaths or permanent disability), additional, more detailed studies are needed to confirm these results. Nevertheless, these findings (and those reported separately in a related article published at the same time in PLoS Medicine) suggest that a significant proportion of the illness associated with malaria may be caused by P. vivax infections. Thus, efforts to reduce or eliminate the malarial burden must target P. vivax as well as P. falciparum in regions where these species coexist. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050127. A PLoSMedicine Research in Translation article by Stephen Rogerson further discusses this study and a related paper on vivax malaria infection in patients attending a regional hospital in Papua, Indonesia The MedlinePlus encyclopedia has a page on malaria (in English and Spanish) The US Centers for Disease Control and Prevention provides information on malaria (in English and Spanish) Information is available from the Roll Back Malaria Partnership on global control of malaria and on malaria in Papua New Guinea Vivaxmalaria provides information for the malaria research community on topics related to Plasmodiumvivax The Malaria Vaccine Initiative also provides a fact sheet on Plasmodiumvivax malaria

Background Delays in accessing care for malaria and other diseases can lead to disease progression, and user fees are a known barrier to accessing health care. Governments are introducing free health care to improve health outcomes. Free health care affects treatment seeking, and it is therefore assumed to lead to improved health outcomes, but there is no direct trial evidence of the impact of removing out-of-pocket payments on health outcomes in developing countries. This trial was designed to test the impact of free health care on health outcomes directly. Methods and Findings 2,194 households containing 2,592 Ghanaian children under 5 y old were randomised into a prepayment scheme allowing free primary care including drugs, or to a control group whose families paid user fees for health care (normal practice); 165 children whose families had previously paid to enrol in the prepayment scheme formed an observational arm. The primary outcome was moderate anaemia (haemoglobin [Hb] < 8 g/dl); major secondary outcomes were health care utilisation, severe anaemia, and mortality. At baseline the randomised groups were similar. Introducing free primary health care altered the health care seeking behaviour of households; those randomised to the intervention arm used formal health care more and nonformal care less than the control group. Introducing free primary health care did not lead to any measurable difference in any health outcome. The primary outcome of moderate anaemia was detected in 37 (3.1%) children in the control and 36 children (3.2%) in the intervention arm (adjusted odds ratio 1.05, 95% confidence interval 0.66–1.67). There were four deaths in the control and five in the intervention group. Mean Hb concentration, severe anaemia, parasite prevalence, and anthropometric measurements were similar in each group. Families who previously self-enrolled in the prepayment scheme were significantly less poor, had better health measures, and used services more frequently than those in the randomised group. Conclusions In the study setting, removing out-of-pocket payments for health care had an impact on health care-seeking behaviour but not on the health outcomes measured. Trial registration: ClinicalTrials.gov (#NCT00146692)., Evelyn Ansah and colleagues report on whether removing user fees has an impact on health care-seeking behavior and health outcomes in households with children in Ghana., Editors' Summary Background. Every year, about 10 million children worldwide die before their fifth birthday. About half these deaths occur in developing countries in sub-Saharan Africa. Here, 166 children out of every 1,000 die before they are five. A handful of preventable diseases—acute respiratory infections, diarrhea, malaria, measles, and HIV/AIDS—are responsible for most of these deaths. For all these diseases, delays in accessing medical care contribute to the high death rate. In the case of malaria, for example, children are rarely taken to a clinic or hospital (formal health care) when they first develop symptoms, which include fever, chills, and anemia (lack of red blood cells). Instead, they are taken to traditional healers or given home remedies (informal health care). When they are finally taken to a clinic, it is often too late to save their lives. Many factors contribute to this delay in seeking formal health care. Sometimes, health care simply isn't available. In other instances, parents may worry about the quality of the service provided or may not seek formal health care because of their sociocultural beliefs. Finally, many parents cannot afford the travel costs and loss of earnings involved in taking their child to a clinic or the cost of the treatment itself. Why Was This Study Done? The financial cost of seeking formal health care is often the major barrier to accessing health care in poor countries. Consequently, the governments of several developing countries have introduced free health care in an effort to improve their nation's health. Such initiatives have increased the use of formal health care in several African countries; the introduction of user fees in Ghana in the early 1980s had the opposite effect. It is generally assumed that an increase in formal health care utilization improves health—but is this true? In this study, the researchers investigate the effect of removing direct payment for health care on health service utilization and health outcomes in Ghanaian children in a randomized controlled trial (a trial in which participants are randomly assigned to an “intervention” group or “control” group and various predefined outcomes are measured). What Did the Researchers Do and Find? The researchers enrolled nearly 2,600 children under the age of 5 y living in a poor region of Ghana. Half were assigned to the group in which a prepayment scheme (paid for by the trial) provided free primary and basic secondary health care—this was the intervention arm. The rest were assigned to the control group in which families paid for health care. The trial's main outcome was the percentage of children with moderate anemia at the end of the malaria transmission season, an indicator of the effect of the intervention on malaria-related illness. Other outcomes included health care utilization (calculated from household diaries), severe anemia, and death. The researchers report that the children in the intervention arm attended formal health care facilities slightly more often and informal health care providers slightly less often than those in the control arm. About 3% of the children in both groups had moderate anemia at the end of the malaria transmission season. In addition, similar numbers of deaths, cases of severe anemia, fever episodes, and known infections with the malaria parasite were recorded in both groups of children. What Do These Findings Mean? These findings show that, in this setting, the removal of out-of-pocket payments for health care changed health care-seeking behavior but not health outcomes in children. This lack of a measured effect does not necessarily mean that the provision of free health care has no effect on children's health—it could be that the increase in health care utilization in the intervention arm compared to the control arm was too modest to produce a clear effect on health. Alternatively, in Ghana, the indirect costs of seeking health care may be more important than the direct cost of paying for treatment. Although the findings of this trial may not be generalizable to other countries, they nevertheless raise the possibility that providing free health care might not be the most cost-effective way of improving health in all developing countries. Importantly, they also suggest that changes in health care utilization should not be used in future trials as a proxy measure of improvements in health. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000007. This research article is further discussed in a PLoS Medicine Perspective by Valéry Ridde and Slim Haddad The World Health Organization provides information on child health and on global efforts to reduce child mortality, Millennium Development Goal 4; it also provides information about health in Ghana The United Nations Web site provides further information on all the Millennium Development Goals, which were agreed to by the nations of the world in 2000 with the aim of ending extreme poverty by 2015 (in several languages) The UK Department for International Development also provides information on the progress that is being made toward reducing child mortality

Background World Health Organization (WHO) guidelines for monitoring HIV-infected individuals taking combination antiretroviral therapy (cART) in resource-limited settings recommend using CD4+ T cell (CD4) count changes to monitor treatment effectiveness. In practice, however, falling CD4 counts are a consequence, rather than a cause, of virologic failure. Adherence lapses precede virologic failure and, unlike CD4 counts, data on adherence are immediately available to all clinics dispensing cART. However, the accuracy of adherence assessments for predicting future or detecting current virologic failure has not been determined. The goal of this study therefore was to determine the accuracy of adherence assessments for predicting and detecting virologic failure and to compare the accuracy of adherence-based monitoring approaches with approaches monitoring CD4 count changes. Methodology and Findings We conducted an observational cohort study among 1,982 of 4,984 (40%) HIV-infected adults initiating non-nucleoside reverse transcriptase inhibitor-based cART in the Aid for AIDS Disease Management Program, which serves nine countries in southern Africa. Pharmacy refill adherence was calculated as the number of months of cART claims submitted divided by the number of complete months between cART initiation and the last refill prior to the endpoint of interest, expressed as a percentage. The main outcome measure was virologic failure defined as a viral load > 1,000 copies/ml (1) at an initial assessment either 6 or 12 mo after cART initiation and (2) after a previous undetectable (i.e., < 400 copies/ml) viral load (breakthrough viremia). Adherence levels outperformed CD4 count changes when used to detect current virologic failure in the first year after cART initiation (area under the receiver operating characteristic [ROC] curves [AUC] were 0.79 and 0.68 [difference = 0.11; 95% CI 0.06 to 0.16; χ2 = 20.1] respectively at 6 mo, and 0.85 and 0.75 [difference = 0.10; 95% CI 0.05 to 0.14; χ2 = 20.2] respectively at 12 mo; p < 0.001 for both comparisons). When used to detect current breakthrough viremia, adherence and CD4 counts were equally accurate (AUCs of 0.68 versus 0.67, respectively [difference = 0.01; 95% CI −0.06 to 0.07]; χ2 = 0.1, p > 0.5). In addition, adherence levels assessed 3 mo prior to viral load assessments were as accurate for virologic failure occurring approximately 3 mo later as were CD4 count changes calculated from cART initiation to the actual time of the viral load assessments, indicating the potential utility of adherence assessments for predicting future, rather than simply detecting current, virologic failure. Moreover, combinations of CD4 count and adherence data appeared useful in identifying patients at very low risk of virologic failure. Conclusions Pharmacy refill adherence assessments were as accurate as CD4 counts for detecting current virologic failure in this cohort of patients on cART and have the potential to predict virologic failure before it occurs. Approaches to cART scale-up in resource-limited settings should include an adherence-based monitoring approach., Analyzing pharmacy and laboratory records from 1,982 patients beginning HIV therapy in southern Africa, Gregory Bisson and colleagues find medication adherence superior to CD4 count changes in identifying treatment failure., Editors' Summary Background. Globally, more than 30 million people are infected with the human immunodeficiency virus (HIV), the cause of acquired immunodeficiency syndrome (AIDS). Combinations of antiretroviral drugs that hold HIV in check (viral suppression) have been available since 1996. Unfortunately, most of the people affected by HIV/AIDS live in developing countries and cannot afford these expensive drugs. As a result, life expectancy has plummeted and economic growth has reversed in these poor countries since the beginning of the AIDS pandemic. Faced with this humanitarian crisis, the lack of access to HIV treatment was declared a global health emergency in 2003. Today, through the concerted efforts of governments, international organizations, and funding bodies, about a quarter of the HIV-positive people in developing and transitional countries who are in immediate need of life-saving, combination antiretroviral therapy (cART) receive the drugs they need. Why Was This Study Done? To maximize the benefits of cART, health-care workers in developing countries need simple, affordable ways to monitor viral suppression in their patients—a poor virologic response to cART can lead to the selection of drug-resistant HIV, rapid disease progression, and death. In developed countries, virologic response is monitored by measuring the number of viral particles in patients' blood (viral load) but this technically demanding assay is unavailable in most developing countries. Instead, the World Health Organization recommends that CD4+ T cell (CD4) counts be used to monitor patient responses to cART in resource-limited settings. HIV results in loss of CD4 cells (a type of immune system cell), so a drop in a patient's CD4 count often indicates virologic failure (failure of treatment to suppress the virus). However, falling CD4 counts are often a result of virologic failure and therefore monitoring CD4 counts for drops is unlikely to prevent virologic failure from occurring. Rather, falling CD4 counts are often used only to guide a change to new medicines, which may be even more expensive or difficult to take. On the other hand “adherence lapses”—the failure to take cART regularly—often precede virologic failure, so detecting them early provides an opportunity for improvement in adherence that could prevent virologic failure. Because clinics that dispense cART routinely collect data that can be used to calculate adherence, in this study the researchers investigate whether assessing adherence might provide an alternative, low-cost way to monitor and predict virologic failure among HIV-infected adults on cART. What Did the Researchers Do and Find? The Aid for AIDS Disease Management Program provides cART to medical insurance fund subscribers in nine countries in southern Africa. Data on claims for antiretroviral drugs made through this program, plus CD4 counts assessed at about 6 or 12 months after initiating cART, and viral load measurements taken within 45 days of a CD4 count, were available for nearly 2,000 HIV-positive adults who had been prescribed a combination of HIV drugs including either efavirenz or nevirapine. The researchers defined adherence as the number of months of cART claims submitted divided by the number of complete months between cART initiation and the last pharmacy refill before a viral load assessment was performed. Virologic failure was defined in two ways: as a viral load of more than 1,000 copies per ml of blood 6 or 12 months after cART initiation, or as a rebound of viral load to similar levels after a previously very low reading (breakthrough viremia). The researchers' statistical analysis of these data shows that at 6 and 12 months after initiation of cART, adherence levels indicated virologic failure more accurately than CD4 count changes. For breakthrough viremia, both measurements were equally accurate. Adherence levels during the first 3 months of cART predicted virologic failure at 6 months as accurately as did CD4 count changes since cART initiation. Finally, the combination of adherence levels and CD4 count changes accurately identified patients at very low risk of virologic failure. What Do These Findings Mean? These findings suggest that adherence assessments (based in this study on insurance claims for pharmacy refills) can identify the patients on cART who are at high and low risk of virologic failure at least as accurately as CD4 counts. In addition, they suggest that adherence assessments could be used for early identification of patients at high risk of virologic failure, averting the health impact of treatment failure and the cost of changing to second-line drug regimens. Studies need to be done in other settings (in particular, in public clinics where cART is provided without charge) to confirm the generalizability of these findings. These finding do not change that fact that monitoring CD4 counts plays an important role in deciding when to start cART or indicating when cART is no longer protecting the immune system. But, write the researchers, systematic monitoring of adherence to cART should be considered as an alternative to CD4 count monitoring in patients who are receiving cART in resource-limited settings or as a way to direct the use of viral load testing where feasible. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050109. This study is discussed further in a PLoS Medicine Perspective by David Bangsberg Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS HIV InSite has comprehensive information on all aspects of HIV/AIDS, including an article about adherence to antiretroviral therapy Information is available from Avert, an international AIDS charity, on HIV and AIDS in Africa and on providing AIDS drug treatment for millions The World Health Organization provides information about universal access to HIV treatment (in several languages) and on its recommendations for antiretroviral therapy for HIV infection in adults and adolescents The US Centers for Disease Control and Prevention also provides information on global efforts to deal with the HIV/AIDS pandemic (in English and Spanish)

World Health Organization (WHO) guidelines for monitoring HIV-infected individuals taking combination antiretroviral therapy (cART) in resource-limited settings recommend using CD4(+) T cell (CD4) count changes to monitor treatment effectiveness. In practice, however, falling CD4 counts are a consequence, rather than a cause, of virologic failure. Adherence lapses precede virologic failure and, unlike CD4 counts, data on adherence are immediately available to all clinics dispensing cART. However, the accuracy of adherence assessments for predicting future or detecting current virologic failure has not been determined. The goal of this study therefore was to determine the accuracy of adherence assessments for predicting and detecting virologic failure and to compare the accuracy of adherence-based monitoring approaches with approaches monitoring CD4 count changes.We conducted an observational cohort study among 1,982 of 4,984 (40%) HIV-infected adults initiating non-nucleoside reverse transcriptase inhibitor-based cART in the Aid for AIDS Disease Management Program, which serves nine countries in southern Africa. Pharmacy refill adherence was calculated as the number of months of cART claims submitted divided by the number of complete months between cART initiation and the last refill prior to the endpoint of interest, expressed as a percentage. The main outcome measure was virologic failure defined as a viral load > 1,000 copies/ml (1) at an initial assessment either 6 or 12 mo after cART initiation and (2) after a previous undetectable (i.e., < 400 copies/ml) viral load (breakthrough viremia). Adherence levels outperformed CD4 count changes when used to detect current virologic failure in the first year after cART initiation (area under the receiver operating characteristic [ROC] curves [AUC] were 0.79 and 0.68 [difference = 0.11; 95% CI 0.06 to 0.16; chi(2) = 20.1] respectively at 6 mo, and 0.85 and 0.75 [difference = 0.10; 95% CI 0.05 to 0.14; chi(2) = 20.2] respectively at 12 mo; p < 0.001 for both comparisons). When used to detect current breakthrough viremia, adherence and CD4 counts were equally accurate (AUCs of 0.68 versus 0.67, respectively [difference = 0.01; 95% CI -0.06 to 0.07]; chi(2) = 0.1, p > 0.5). In addition, adherence levels assessed 3 mo prior to viral load assessments were as accurate for virologic failure occurring approximately 3 mo later as were CD4 count changes calculated from cART initiation to the actual time of the viral load assessments, indicating the potential utility of adherence assessments for predicting future, rather than simply detecting current, virologic failure. Moreover, combinations of CD4 count and adherence data appeared useful in identifying patients at very low risk of virologic failure.Pharmacy refill adherence assessments were as accurate as CD4 counts for detecting current virologic failure in this cohort of patients on cART and have the potential to predict virologic failure before it occurs. Approaches to cART scale-up in resource-limited settings should include an adherence-based monitoring approach.

The tools and strategies of syndromic surveillance, say the authors, hold promise for improving public health security in developing countries.

Background The roll-out of antiretroviral treatment (ART) in developing countries concentrates on finding patients currently in need, but over time many HIV-infected individuals will be identified who will require treatment in the future. We investigated the potential influence of alternative patient management and ART initiation strategies on the impact of ART programmes in sub-Saharan Africa. Methods and Findings We developed a stochastic mathematical model representing disease progression, diagnosis, clinical monitoring, and survival in a cohort of 1,000 hypothetical HIV-infected individuals in Africa. If individuals primarily enter ART programmes when symptomatic, the model predicts that only 25% will start treatment and, on average, 6 life-years will be saved per person treated. If individuals are recruited to programmes while still healthy and are frequently monitored, and CD4+ cell counts are used to help decide when to initiate ART, three times as many are expected to be treated, and average life-years saved among those treated increases to 15. The impact of programmes can be improved further by performing a second CD4+ cell count when the initial value is close to the threshold for starting treatment, maintaining high patient follow-up rates, and prioritising monitoring the oldest (≥ 35 y) and most immune-suppressed patients (CD4+ cell count ≤ 350). Initiating ART at higher CD4+ cell counts than WHO recommends leads to more life-years saved, but disproportionately more years spent on ART. Conclusions The overall impact of ART programmes will be limited if rates of diagnosis are low and individuals enter care too late. Frequently monitoring individuals at all stages of HIV infection and using CD4 cell count information to determine when to start treatment can maximise the impact of ART., Using a stochastic model based on data from Africa, Timothy Hallett and colleagues find that starting HIV treatment based on regular CD4 monitoring, rather than on symptoms, would substantially increase survival., Editors' Summary Background. Acquired immunodeficiency syndrome (AIDS) has killed more than 25 million people since the first case in 1981, and about 33 million people are currently infected with the human immunodeficiency virus (HIV), which causes AIDS. HIV destroys immune system cells (including CD4 cells, a type of lymphocyte), leaving infected individuals susceptible to other infections. Early in the AIDS epidemic, most HIV-positive individuals died within 10 years but in 1996, combination antiretroviral therapy (ART)—a mixture of powerful but expensive antiretroviral drugs—was developed. For HIV-positive people living in affluent, developed countries who could afford ART, AIDS then became a chronic disease, but for those living in low- and middle-income countries it remained a death sentence—ART was too expensive. In 2003, this lack of access to ART was declared a global health emergency and governments, international organizations, and funding bodies began to implement plans to increase ART coverage in developing countries. Why Was This Study Done? The roll-out of ART in developing countries has concentrated so far on finding HIV-positive people who currently need treatment. In developing countries, these are often individuals who have AIDS-related symptoms such as recurrent severe bacterial infections. But healthy people are also being diagnosed as HIV positive during voluntary testing and at antenatal clinics. How should these HIV-positive but symptom-free individuals be managed? Should regular health-monitoring appointments be scheduled for them and when should ART be initiated? Management decisions like these will determine how well patients do when they eventually start ART, as well as the demand for ART and other health-care services. The full range of alternative patient management strategies cannot be tested in clinical trials—it would be unethical—but public-health officials need an idea of their relative effectiveness in order to use limited resources wisely. In this study, therefore, the researchers use mathematical modeling to investigate the impact of alternative patient management and ART initiation strategies on the impact of ART programs in resource-poor settings. What Did the Researchers Do and Find? The researchers' mathematical model, which includes data on disease progression collected in Africa, simulates disease progression in a group (cohort) of 1,000 HIV-infected adults. It tracks these individuals from infection, through diagnosis and clinical monitoring, and into treatment and predicts how many will receive ART and their length of survival under different management scenarios and ART initiation rules. The model predicts that if HIV-positive individuals receive ART only when they have AIDS-related symptoms, only a quarter of them will ever start ART and the average life-years saved per person treated will be 6 years (that is, they will live 6 years longer than they would have done without treatment). If individuals are recruited to ART programs when they are healthy and are frequently monitored using CD4 cell counts to decide when to start ART, three-quarters of the cohort will be treated and 15 life-years will be saved per person treated. The impact of ART programs will be increased further, the model predicts, by preferentially monitoring people who are more than 35 years old and the most immunosuppressed individuals. Finally, strategies that measure CD4 cells frequently will save more life-years because ART is more likely to be started before the immune system is irreversibly damaged. Importantly for resource-poor settings, these strategies also save more life-years per year on ART. What Do These Findings Mean? As with all mathematical models, the accuracy of these predictions depends on the assumptions built into the model and the reliability of the data fed into it. Also, this model does not estimate the costs of the various management options, something that will need to be done to ensure effective allocation of limited resources. Nevertheless, these findings provide several general clues about how ART programs should be implemented in poor countries to maximize their effects. Early diagnosis of infections, regular monitoring of patients, and using CD4 cell counts to decide when to initiate ART should all help to improve the number of life-years saved by ART. In other words, the researchers conclude, effectively managing individuals at all stages of HIV infection is essential to maximize the impact of ART. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/doi:10.1371/journal.pmed.0050053. Information from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS. Information from the US Centers for Disease Control and Prevention on global HIV/AIDS topics (in English and Spanish) HIV InSite, comprehensive and up-to-date information on all aspects of HIV/AIDS from the University of California, San Francisco Information from Avert, an international AIDS charity, on HIV and AIDS in Africa and on HIV/AIDS treatment and care, including universal access to ART Progress toward universal access to HIV/AIDS treatment, the latest report from the World Health Organization (available in several languages) Guidelines for antiretroviral therapy in adults and adolescents are provided by the World Health Organization and by the US Department of Health and Human Services

Background The efficient allocation of financial resources for malaria control using appropriate combinations of interventions requires accurate information on the geographic distribution of malaria risk. An evidence-based description of the global range of Plasmodium falciparum malaria and its endemicity has not been assembled in almost 40 y. This paper aims to define the global geographic distribution of P. falciparum malaria in 2007 and to provide a preliminary description of its transmission intensity within this range. Methods and Findings The global spatial distribution of P. falciparum malaria was generated using nationally reported case-incidence data, medical intelligence, and biological rules of transmission exclusion, using temperature and aridity limits informed by the bionomics of dominant Anopheles vector species. A total of 4,278 spatially unique cross-sectional survey estimates of P. falciparum parasite rates were assembled. Extractions from a population surface showed that 2.37 billion people lived in areas at any risk of P. falciparum transmission in 2007. Globally, almost 1 billion people lived under unstable, or extremely low, malaria risk. Almost all P. falciparum parasite rates above 50% were reported in Africa in a latitude band consistent with the distribution of Anopheles gambiae s.s. Conditions of low parasite prevalence were also common in Africa, however. Outside of Africa, P. falciparum malaria prevalence is largely hypoendemic (less than 10%), with the median below 5% in the areas surveyed. Conclusions This new map is a plausible representation of the current extent of P. falciparum risk and the most contemporary summary of the population at risk of P. falciparum malaria within these limits. For 1 billion people at risk of unstable malaria transmission, elimination is epidemiologically feasible, and large areas of Africa are more amenable to control than appreciated previously. The release of this information in the public domain will help focus future resources for P. falciparum malaria control and elimination., Combining extensive surveillance and climate data, as well as biological characteristics of Anopheles mosquitoes, Robert Snow and colleagues create a global map of risk for P. falciparum malaria., Editors' Summary Background. Malaria is a parasitic disease that occurs in tropical and subtropical regions of the world. 500 million cases of malaria occur every year, and one million people, mostly children living in sub-Saharan Africa, die as a result. The parasite mainly responsible for these deaths—Plasmodium falciparum—is transmitted to people through the bites of infected mosquitoes. These insects inject a life stage of the parasite called sporozoites, which invade and reproduce in human liver cells. After a few days, the liver cells release merozoites (another life stage of the parasite), which invade red blood cells. Here, they multiply before bursting out and infecting more red blood cells, causing fever and damaging vital organs. Infected red blood cells also release gametocytes, which infect mosquitoes when they take a human blood meal. In the mosquito, the gametocytes multiply and develop into sporozoites, thus completing the parasite's life cycle. Malaria can be treated with antimalarial drugs and can be prevented by controlling the mosquitoes that spread the parasite (for example, by using insecticides) and by avoiding mosquito bites (for example, by sleeping under a insecticide-treated bednet). Why Was This Study Done? Because malaria poses such a large global public-health burden, many national and international agencies give countries where malaria is endemic (always present) financial resources for malaria control and, where feasible, elimination. The efficient allocation of these resources requires accurate information on the geographical distribution of malaria risk, but it has been 40 years since a map of malaria risk was assembled. In this study, which is part of the Malaria Atlas Project, the researchers have generated a new global map to show where the risk of P. falciparum transmission is moderate or high (stable transmission areas where malaria is endemic) and areas where the risk of transmission is low (unstable transmission areas where sporadic outbreaks of malaria occur). What Did the Researchers Do and Find? To construct their map of P. falciparum risk, the researchers collected nationally reported data on malaria cases each year and on the number of people infected in sampled communities. They also collected information about climatic conditions that affect the parasite's life cycle and consequently the likelihood of active transmission. For example, below a certain temperature, infected mosquitoes reach the end of their natural life span before the parasite has had time to turn into infectious sporozoites, which means that malaria transmission does not occur. By combining these different pieces of information with global population data, the researchers calculated that 2.37 billion people (about 35% of the world's population) live in areas where there is some risk of P. falciparum transmission, and that about 1 billion of these people live where there is a low but still present risk of malaria transmission. Furthermore, nearly all the regions where more than half of children carry P. falciparum parasites (a P. falciparum prevalence of more than 50%) are in Africa, although there are some African regions where few people are infected with P. falciparum. Outside Africa, the P. falciparum prevalence is generally below 5%. What Do These Findings Mean? The accuracy of this new map of the spatial distribution of P. falciparum malaria risk depends on the assumptions made in its assembly and the accuracy of the data fed into it. Nevertheless, by providing a contemporary indication of global patterns of P. falciparum malaria risk, this new map should be a valuable resource for agencies that are trying to control and eliminate malaria. (A similar map for the more common but less deadly P. vivax malaria would also be useful, but has not yet been constructed because less information is available and its biology is more complex.) Importantly, the map provides an estimate of the number of people who are living in areas where malaria transmission is low, areas where it should, in princple, be possible to use existing interventions to eliminate the parasite. In addition, it identifies large regions of Africa where the parasite might be more amenable to control and, ultimately, elimination than previously thought. Finally, with regular updates, this map will make it possible to monitor the progress of malaria control and elimination efforts. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050038. The MedlinePlus encyclopedia contains a page on malaria (in English and Spanish) Information is available from the World Health Organization on malaria (in English, Spanish, French, Russian, Arabic, and Chinese) The US Centers for Disease Control and Prevention provide information on malaria (in English and Spanish) Information is available from the Roll Back Malaria Partnership on its approach to the global control of malaria More information is available on global mapping of malaria risk from the Malaria Atlas Project

Background to the debate: Demographic surveillance—the process of monitoring births, deaths, causes of deaths, and migration in a population over time—is one of the cornerstones of public health research, particularly in investigating and tackling health disparities. An international network of demographic surveillance systems (DSS) now operates, mostly in sub-Saharan Africa and Asia. Thirty-eight DSS sites are coordinated by the International Network for the Continuous Demographic Evaluation of Populations and Their Health (INDEPTH). In this debate, Daniel Chandramohan and colleagues argue that DSS data in the INDEPTH database should be made available to all researchers worldwide, not just to those within the INDEPTH Network. Basia Żaba and colleagues argue that the major obstacles to DSS sites sharing data are technical, managerial, and financial rather than proprietorial concerns about analysis and publication. This debate is further discussed in this month's Editorial., Chandramohan and colleagues argue that DSS data should be made available to all researchers worldwide, while Żaba and colleagues discuss the major obstacles to DSS sites sharing their data more widely.

The Neglected Diseases section will no longer focus on chronic tropical infections, but on other neglected health problems that have a major global burden.

Background Maternal mortality is a major health problem concentrated in resource-poor regions. Accurate data on its causes using rigorous methods is lacking, but is essential to guide policy-makers and health professionals to reduce this intolerable burden. The aim of this study was to accurately describe the causes of maternal death in order to contribute to its reduction, in one of the regions of the world with the highest maternal mortality ratios. Methods and Findings We conducted a prospective study between October 2002 and December 2004 on the causes of maternal death in a tertiary-level referral hospital in Maputo, Mozambique, using complete autopsies with histological examination. HIV detection was done by virologic and serologic tests, and malaria was diagnosed by histological and parasitological examination. During 26 mo there were 179 maternal deaths, of which 139 (77.6%) had a complete autopsy and formed the basis of this analysis. Of those with test results, 65 women (52.8%) were HIV-positive. Obstetric complications accounted for 38.2% of deaths; haemorrhage was the most frequent cause (16.6%). Nonobstetric conditions accounted for 56.1% of deaths; HIV/AIDS, pyogenic bronchopneumonia, severe malaria, and pyogenic meningitis were the most common causes (12.9%, 12.2%, 10.1% and 7.2% respectively). Mycobacterial infection was found in 12 (8.6%) maternal deaths. Conclusions In this tertiary hospital in Mozambique, infectious diseases accounted for at least half of all maternal deaths, even though effective treatment is available for the four leading causes, HIV/AIDS, pyogenic bronchopneumonia, severe malaria, and pyogenic meningitis. These observations highlight the need to implement effective and available prevention tools, such as intermittent preventive treatment and insecticide-treated bed-nets for malaria, antiretroviral drugs for HIV/AIDS, or vaccines and effective antibiotics for pneumococcal and meningococcal diseases. Deaths due to obstetric causes represent a failure of health-care systems and require urgent improvement., Clara Menendez and colleagues analyze 139 complete autopsies following maternal deaths in Maputo, Mozambique and find a predominance of infectious and preventable causes., Editors' Summary Background. Every year, half a million women—many of them living in developing countries—die during pregnancy or childbirth or within a few weeks of delivery. (The term “maternal deaths” is used to designate such deaths.) For women living in sub-Saharan Africa, the situation is particularly grim. Half of all maternal deaths occur in this region. The maternal mortality ratio (MMR)—the number of maternal deaths per 100,000 live births—in sub-Saharan Africa is nearly 1,000; in industrialized countries it is 8. The lifetime risk of maternal death in sub-Saharan Africa is 1 in 22; in industrialized countries it is 1 in 8,000. Faced with the magnitude of the global maternal death toll, in September 2000 the United Nations pledged, as its fifth Millennium Development Goal, that the global MMR would be reduced to a quarter of its 1990 level by 2015. Currently, it seems unlikely that this target will be met. Between 1990 and 2005 global maternal deaths decreased by only 1% per annum. In sub-Saharan Africa the annual reduction was even less—0.1% per annum. Why Was This Study Done? One reason for this slow progress is that public-health professionals in developing countries rarely have accurate data about the causes of maternal death, information that they need to guide their efforts to reduce these deaths. A detailed examination of the body after death (a medical autopsy) is the only sure way to ascertain the causes of maternal death, but in most developing countries, clinical records and verbal autopsies (asking relatives about the circumstances of the mother's death) are the main sources of these data and neither source is optimally accurate. The currently available information indicates that birth (obstetric) complications are the most frequent causes of maternal death in developing countries, in particular, hemorrhage (uncontrollable bleeding) after the baby is born. However, little is known about the impact of the HIV/AIDS epidemic (which is worst in Sub-Saharan Africa), malaria, or other infectious diseases on maternal deaths. In this study, the researchers use complete autopsies to determine the causes of maternal death in the Maputo Central Hospital, Mozambique, a tertiary-level hospital to which women with high-risk pregnancies are referred for specialized care. What Did the Researchers Do and Find? Between October 2002 and December 2004, there were 179 maternal deaths in the Maputo Central Hospital and 31,135 live births, corresponding to a ratio of 874 maternal deaths per 100,000 live births. (Because the hospital was a referral center, this ratio would not be expected to reflect the actual MMR for the general population of the Maputo area.) Complete autopsies were done on 139 of the women, HIV infection was measured using standard tests, and malaria was diagnosed by looking for parasites and malaria-associated changes in postmortem samples. Of these 139 women, just over one-third died because of obstetric complications; hemorrhage was the most common cause of death (one in six maternal deaths). The commonest nonobstetric causes of maternal death were HIV/AIDS- related conditions, including infections and cancers (about 1 in 8 maternal deaths; about half the women in the study were HIV positive). Other common causes were pyogenic (pus-forming) bacterial infections of the lungs and brain, and malaria. Together, these infectious diseases accounted for nearly half of the maternal deaths. What Do These Findings Mean? These findings indicate that infectious diseases account for a large proportion of maternal deaths at Maputo Central Hospital and identify which obstetric complications are responsible for most maternal deaths in this setting. They may not, however, accurately reflect the causes of maternal death elsewhere in Mozambique. For example, maternal deaths from some obstetric complications may be over-represented in this study because women at risk of these complications would have been referred to this hospital. Conversely, the proportion of women dying from hemorrhage may be higher in the community because this complication usually happens shortly after birth, leaving little time for women to reach a hospital for treatment. Nevertheless, these findings suggest that the implementation of effective measures to prevent and treat HIV/AIDS, malaria, and infections with pyogenic bacteria, together with improvements in health services for obstetric complications, should greatly reduce the maternal death toll in Mozambique and perhaps in other countries in sub-Saharan Africa. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050044. UNICEF (the United Nations Children's Fund) provides information on maternal mortality including the WHO/UNICEF/UNFPA/The World Bank) estimates of maternal mortality for 2005 by country, and an article on maternal mortality in the Cabo Delgado province of Mozambique More information on the WHO/UNICEF/UNFPA/The World Bank estimates of maternal mortality in 2005 The UK Department for International Development provides information about Millenium Development Goal 5: the improvement of maternal health The US Centers for Disease Control and Prevention has a page on pregnancy-related deaths (in English and Spanish) The Partnership for Maternal, Newborn and Child Health provides information on maternal deaths (in English, Spanish, French, Russian, Arabic, and Chinese) The United Nations Development Fund for Women (UNIFEM) focuses on improving conditions for women worldwide, especially those in poverty

Background Pesticide ingestion is a common method of self-harm in the rural developing world. In an attempt to reduce the high case fatality seen with the herbicide paraquat, a novel formulation (INTEON) has been developed containing an increased emetic concentration, a purgative, and an alginate that forms a gel under the acid conditions of the stomach, potentially slowing the absorption of paraquat and giving the emetic more time to be effective. We compared the outcome of paraquat self-poisoning with the standard formulation against the new INTEON formulation following its introduction into Sri Lanka. Methods and Findings Clinical data were prospectively collected on 586 patients with paraquat ingestion presenting to nine large hospitals across Sri Lanka with survival to 3 mo as the primary outcome. The identity of the formulation ingested after October 2004 was confirmed by assay of blood or urine samples for a marker compound present in INTEON. The proportion of known survivors increased from 76/297 with the standard formulation to 103/289 with INTEON ingestion, and estimated 3-mo survival improved from 27.1% to 36.7% (difference 9.5%; 95% confidence interval [CI] 2.0%–17.1%; p = 0.002, log rank test). Cox proportional hazards regression analyses showed an approximately 2-fold reduction in toxicity for INTEON compared to standard formulation. A higher proportion of patients ingesting INTEON vomited within 15 min (38% with the original formulation to 55% with INTEON, p < 0.001). Median survival time increased from 2.3 d (95% CI 1.2–3.4 d) with the standard formulation to 6.9 d (95% CI 3.3–10.7 d) with INTEON ingestion (p = 0.002, log rank test); however, in patients who did not survive there was a comparatively smaller increase in median time to death from 0.9 d (interquartile range [IQR] 0.5–3.4) to 1.5 d (IQR 0.5–5.5); p = 0.02. Conclusions The survey has shown that INTEON technology significantly reduces the mortality of patients following paraquat ingestion and increases survival time, most likely by reducing absorption., Martin Wilks and colleagues compared the outcome of paraquat self-poisoning with the standard formulation against a new formulation following its introduction into Sri Lanka., Editors' Summary Background. Paraquat is a non-selective herbicide used in many countries on a variety of crops including potatoes, rice, maize, tea, cotton, and bananas. It is fast-acting, rainfast, and facilitates “no-till” farming, but it has attracted controversy because of the potential for misuse, particularly in developing countries. Better training of workers has been shown to reduce the number of accidents, and additions to the liquid formulation have contributed to a reduction in cases where paraquat was drunk by mistake—blue color and a stench agent made it less attractive to drink, and an emetic to induce vomiting aimed to reduce the time it is retained in the body. Why Was This Study Done? Despite the changes made to the formulation, paraquat is still taken deliberately as a poison by agricultural workers in parts of the developing world. Although other pesticides cause more deaths overall, paraquat poisoning is more frequently fatal than other common pesticides. Syngenta, a commercial producer of paraquat, has developed a new paraquat formulation designed to reduce its toxicity. Syngenta introduced the new formulation in Sri Lanka, a country well known for its high level of suicides with pesticides, in 2004. This new formulation includes three components designed to reduce paraquat absorption from the stomach and intestines: a gelling agent to thicken the formulation in the acidic environment of the stomach and slow its passage into the small intestine; an increase in the amount of emetic to induce more vomiting more quickly; and a purgative to speed its exit from the small intestine, the main site of its absorption. The researchers wished to know whether the new formulation could contribute to improved survival in instances where paraquat had been ingested. What Did the Researchers Do and Find? The researchers gathered information on the time and circumstances of when paraquat was taken, the amount that was taken, the times, and details of any vomiting, treatment, and outcomes for cases of attempted suicide by paraquat poisoning at nine large hospitals in agricultural regions of Sri Lanka from December 2003 to January 2006. In total, 774 patients were tracked in this time. Syngenta introduced the new formulation in Sri Lanka on 1 October 2004. The researchers gathered information on the formulation involved in subsequent cases, by either interview or analysis of samples. After excluding some unusual or less certain cases, they analyzed data on 586 patients, of whom 297 had deliberately taken the standard formulation and 289 the new formulation. Although the new formulation was still toxic, the data showed an increase in the proportion of cases surviving for at least three months—from 27% (standard formulation) to 37% (new formulation), an effect that was unlikely to be due to chance. More patients vomited within 15 minutes of taking the new formulation of paraquat. Patients who died generally survived longer if they had taken the new rather than the standard formulation. The researchers estimated that the new formulation is just over half as toxic as the standard formulation, meaning that a patient was likely to suffer the same level of ill effects after taking twice as much of the new formulation compared to the standard formulation. What Do these Findings Mean? This study was designed, funded, and led by Syngenta, the manufacturer of the standard and new formulations of paraquat but the study team included a number of independent Sri Lankan and international scientists. As the researchers observed the effects of the introduction of the new formulation across the entire country at the same time, they could not completely rule out other possible reasons for the differences in outcomes for those who had taken the two formulations, such as differences in treatment. Despite this inherent drawback, the researchers estimate that during the study the new formulation saved about 30 lives. They conclude that the the new formulation does reduce the amount of paraquat absorbed by the body, although the study does not answer the question whether this was due to the gelling agent, the increased emetic in the new formulation or a combination of factors. The researchers suggest that the new formulation, by keeping patients alive longer, may allow doctors more time to treat patients. As no effective treatment exists at present, this benefit relies on a treatment being developed in the future. The researchers note that the most important factor in predicting the outcome when paraquat has been taken deliberately is the dose. As a result, they suggest that the new formulation can only be one part of a wider strategy to reduce deaths by deliberate self-poisoning using paraquat. They suggest that such an integrated approach might include generic measures to reduce incidents of self-harm, reduced access to paraquat, reduced formulation strength, and improvements in treatment. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050049. The US Environmental Protection Agency has published its Reregistration Eligibility Decision for paraquat The Department of Health and Human Services of the US Centers for Disease Control and Prevention provides a fact sheet on how to handle paraquat and suspected cases of exposure The World Health Organisation has recently finished consulting on a draft Poisons Information Monograph for paraquat The International Programme on Chemical Safety (IPCS) has published a review of paraquat in its Environmental Health Criteria Series MedlinePlus provides links to information on health effects of paraquat

While the number of new detected cases of HAT is falling, say the authors, sleeping sickness could suffer the "punishment of success," receiving lower priority by public and private health institutions.

[Introduction] Recent experience with SARS (severe acute respiratory syndrome) [1] and avian flu shows that the public and political response to threats from new\ud anthropozoonoses can be near-hysteria. This can readily make\ud us forget more classical animal-borne diseases, such as plague (Box 1).\ud Three recent international meetings on plague (Box 2)\ud concluded that: (1) it should be re-emphasised that the\ud plague bacillus (Yersinia pestis) still causes several thousand human cases per year [2,3] (Figure 1); (2) locally perceived risks far outstrip the objective risk based purely on the number of cases [2]; (3) climate change might increase the risk of plague outbreaks where plague is currently endemic and new plague areas might arise [2,4]; (4) remarkably little is known about the dynamics of plague in its natural reservoirs and hence about changing risks for humans [5]; and, therefore, (5) plague should be taken much more seriously by the international community than appears to be the case.

Others have made the point convincingly that Millennium Development Goal 4, a reinvigorated commitment to reduce child mortality by two-thirds before 2015, could be achieved if existing interventions were implemented on a massive scale [1,2]. Widespread access to simple therapeutic interventions, in accordance with World Heath Organization (WHO) case management guidelines, is a substantial part of this package. Assuming that the coverage of existing interventions can be improved, what will be the next major challenge? We believe it will be enabling groups of countries, individual countries, or even large states to take increasing responsibility for the future of their case management strategies. Here we bring together insights from a wide range of disciplines to propose a framework for national surveillance, monitoring, and research that could help inform guideline development in low-income settings. Although our focus is on childhood illness, the principles might be applied more widely.

Schistosomiasis is a tropical disease of great antiquity that remains endemic in 76 countries, affecting 200 to 300 million people in the developing world. Current control of schistosomiasis is heavily dependent on chemotherapy, primarily through praziquantel, a safe and highly effective drug introduced in the early 1980s. In recent decades, large-scale school- or community-based treatment strategies have been successful in suppressing average infection intensity in many parts of the world, dramatically reducing schistosomiasis-associated morbidities such as hepatosplenomegaly, hepatic fibrosis, or bladder and kidney inflammation for urinary schistosomiasis [1,2]. We expect to see a similar pattern in low-income countries, particularly in sub-Saharan Africa, as praziquantel is made increasingly available [3]. However, increasing evidence shows that chemotherapy-based strategies alone are unlikely to be a sustainable strategy for prevention of schistosome infections in all endemic areas [2,4,5]. This evidence has two important implications. First, although advanced stages of schistosomiasis can be effectively controlled through praziquantel use, there is evidence that light chronic infections due to continuing transmission contribute significantly to chronic morbidities such as growth retardation, anemia, exercise intolerance, poor school performance, and lower work capacity [6]. Second, drug treatment does not change the environmental conditions that foster transmission of the parasite in endemic communities [2,4]. In some environments, the cessation of treatment even for a few years can result in a re-occurrence of high levels of infection, even back to pretreatment levels in extreme cases [7,8]. Hence, there is a pressing need to return to a more comprehensive strategy for suppressing schistosomiasis transmission beyond drug treatment. Linked Research Article This Perspective discusses the following new study published in PLoS Medicine: Riley S, Carabin H, Belisle P, Joseph L, Tallo V, et al. (2008) Multi-host transmission dynamics of Schistosoma japonicum in Samar Province, the Philippines. PLoS Med 5(1): e18. doi:10.1371/journal.pmed.0050018 Obtaining schistosome infection data from thousands of humans and mammalian hosts in the Philippines, Steven Riley and colleagues find that mammalian acquisition, rather than transmission to snails, drives prevalence. In the continuing absence of viable vaccines against the schistosome, there is reason to reconsider earlier approaches targeting the parasite transmission cycle to augment the chemotherapy-based strategy. However, such approaches (e.g., mollusciciding, improved sanitation, and provision of safe water) require significantly greater financial resources than does chemotherapy. To make best use of limited resources, the key is to identify and target control efforts at locally vulnerable stages of the transmission cycle. Although the complete life cycle of the schistosome was described almost a century ago, characterizing local or regional vulnerabilities of the parasite-snail-host interaction still remains a challenging task because of its complex dependence on agricultural and other ecological factors. This is particularly true for Schistosoma japonicum, which, in contrast to other species of schistosome, has a number of nonhuman mammalian hosts. The contribution of these zoonotic carriers to transmission is seldom well characterized [9]. In a new study in PLoS Medicine, Steven Riley and colleagues present an analysis using a mathematical model complemented with statistical approaches to unravel this particular aspect of the transmission cycle in an endemic region in the Philippines [10].

Background The provision of highly active antiretroviral therapy (HAART) in resource-limited settings follows a public health approach, which is characterised by a limited number of regimens and the standardisation of clinical and laboratory monitoring. In industrialized countries doctors prescribe from the full range of available antiretroviral drugs, supported by resistance testing and frequent laboratory monitoring. We compared virologic response, changes to first-line regimens, and mortality in HIV-infected patients starting HAART in South Africa and Switzerland. Methods and Findings We analysed data from the Swiss HIV Cohort Study and two HAART programmes in townships of Cape Town, South Africa. We included treatment-naïve patients aged 16 y or older who had started treatment with at least three drugs since 2001, and excluded intravenous drug users. Data from a total of 2,348 patients from South Africa and 1,016 patients from the Swiss HIV Cohort Study were analysed. Median baseline CD4+ T cell counts were 80 cells/μl in South Africa and 204 cells/μl in Switzerland. In South Africa, patients started with one of four first-line regimens, which was subsequently changed in 514 patients (22%). In Switzerland, 36 first-line regimens were used initially, and these were changed in 539 patients (53%). In most patients HIV-1 RNA was suppressed to 500 copies/ml or less within one year: 96% (95% confidence interval [CI] 95%–97%) in South Africa and 96% (94%–97%) in Switzerland, and 26% (22%–29%) and 27% (24%–31%), respectively, developed viral rebound within two years. Mortality was higher in South Africa than in Switzerland during the first months of HAART: adjusted hazard ratios were 5.90 (95% CI 1.81–19.2) during months 1–3 and 1.77 (0.90–3.50) during months 4–24. Conclusions Compared to the highly individualised approach in Switzerland, programmatic HAART in South Africa resulted in similar virologic outcomes, with relatively few changes to initial regimens. Further innovation and resources are required in South Africa to both achieve more timely access to HAART and improve the prognosis of patients who start HAART with advanced disease., Comparing HIV treatment in Switzerland, where drug selection is individualized, and South Africa, where a programmatic approach is used, Matthias Egger and colleagues find similar virologic outcomes over two years., Editors' Summary Background. Acquired immunodeficiency syndrome (AIDS) has killed more than 25 million people since the first reported case in 1981, and more than 30 million people are now infected with the human immunodeficiency virus (HIV), which causes AIDS. HIV destroys immune system cells (including CD4 cells, a type of lymphocyte), leaving infected individuals susceptible to other infections. Early in the AIDS epidemic, most HIV-infected people died within 10 years of becoming infected. Then, in 1996, highly active antiretroviral therapy (HAART)—a combination of several antiretroviral drugs—was developed. Now, in resource-rich countries, clinicians provide individually tailored care for HIV-infected people by prescribing combinations of antiretroviral drugs chosen from more than 20 approved medicines. The approach to treatment of HIV in developed countries typically also includes frequent monitoring of the amount of virus in patients' blood (viral load), viral resistance testing (to see whether any viruses are resistant to specific antiretroviral drugs), and regular CD4 cell counts (an indication of immune-system health). Since the implementation of these interventions, the health and life expectancy of people with HIV has improved dramatically in these countries. Why Was This Study Done? The history of HIV care in resource-poor countries has been very different. Initially, these countries could not afford to provide HAART for their populations. In 2003, however, governments, international agencies, and funding bodies began to implement plans to increase HAART coverage in developing countries. By December 2006, more than a quarter of the HIV-infected people in low- and middle-income countries who urgently needed treatment were receiving HAART. However, instead of individualized treatment, HAART programs in developing countries follow a public-health approach developed by the World Health Organization. That is, drug regimens, clinical decision-making, and clinical and laboratory monitoring are all standardized. This public-health approach takes into account the realities of under-resourced health systems, but is it as effective as the individualized approach? The researchers addressed this question by comparing virologic responses (the effect of treatment on the viral load), changes to first-line (initial) therapy, and deaths in patients receiving HAART in South Africa (public-health approach) and in Switzerland (individualized approach). What Did the Researchers Do and Find? The researchers analyzed data collected since 2001 from more than 2,000 patients enrolled in HAART programs in two townships (Gugulethu and Khayelitsha) in Cape Town, South Africa, and from more than 1,000 patients enrolled in the Swiss HIV Cohort Study, a nationwide study of HIV-infected people. The patients in South Africa, who had a lower starting CD4 cell count and were more likely to have advanced AIDS than the patients in Switzerland, started their treatment for HIV infection with one of four first-line therapies, and about a quarter changed to a second-line therapy during the study. By contrast, 36 first-line regimens were used in Switzerland and half the patients changed to a different regimen. Despite these differences, the viral load was greatly reduced within a year in virtually all the patients and viral rebound (an increased viral load after a low measurement) developed within 2 years in a quarter of the patients in both countries. However, more patients died in South Africa than in Switzerland, particularly during the first 3 months of therapy. What Do These Findings Mean? These findings suggest that the public-health approach to HAART practiced in South Africa is as effective in terms of virologic outcomes as the individualized approach practiced in Switzerland. This is reassuring because it suggests that “antiretroviral anarchy” (the unregulated use of antiretroviral drugs, interruptions in drug supplies, and the lack of treatment monitoring), which is likely to lead to the emergence of viral resistance, is not happening in South Africa as some experts feared it might. Thus, these findings support the continued rollout of the public-health approach to HAART in resource-poor countries. Conversely, they also suggest that a more standardized approach to HAART could be taken in Switzerland (and in other industrialized countries) without compromising its effectiveness. Finally, the higher mortality in South Africa than in Switzerland, which partly reflects the many patients in South Africa in desperate need of HAART and their more advanced disease at the start of therapy, suggests that HIV-infected patients in South Africa and in other resource-limited countries would benefit from earlier initiation of therapy. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050148. The World Health Organization provides information about universal access to HIV treatment (in several languages) and on its recommendations for a public-health approach to antiretroviral therapy for HIV infection More details on the Swiss HIV Cohort Study and on the studies in Gugulethu and Khayelitsha are available Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS HIV InSite has comprehensive information on all aspects of HIV/AIDS, including detailed information about antiretroviral therapy and links to treatment guidelines for various countries Information is available from Avert, an international AIDS charity, on HIV and AIDS around the world and on providing AIDS drug treatment for millions

Pneumonia is the single commonest cause of death in children under five years old, accounting for 2 million out of 10 million childhood deaths worldwide [1]. Severe pneumonia is an important diagnostic syndrome within the World Health Organization (WHO)/UNICEF system for triage and clinical management in developing countries, the Integrated Management of Childhood Illness (IMCI). The objective of IMCI is early recognition of disease and timely access to effective therapy; for severe pneumonia, this means referral to hospital and treatment with lifesaving antibiotics directed against the principal etiological agents, Streptococcus pneumoniae and Haemophilus influenzae type b (Hib) [2].

Background The generation of broadly neutralizing antibodies is a priority in the design of vaccines against HIV-1. Unfortunately, most antibodies to HIV-1 are narrow in their specificity, and a basic understanding of how to develop antibodies with broad neutralizing activity is needed. Designing methods to target antibodies to conserved HIV-1 epitopes may allow for the generation of broadly neutralizing antibodies and aid the global fight against AIDS by providing new approaches to block HIV-1 infection. Using a naturally occurring HIV-1 Envelope (Env) variant as a template, we sought to identify features of Env that would enhance exposure of conserved HIV-1 epitopes. Methods and Findings Within a cohort study of high-risk women in Mombasa, Kenya, we previously identified a subtype A HIV-1 Env variant in one participant that was unusually sensitive to neutralization. Using site-directed mutagenesis, the unusual neutralization sensitivity of this variant was mapped to two amino acid mutations within conserved sites in the transmembrane subunit (gp41) of the HIV-1 Env protein. These two mutations, when introduced into a neutralization-resistant variant from the same participant, resulted in 3- to >360-fold enhanced neutralization by monoclonal antibodies specific for conserved regions of both gp41 and the Env surface subunit, gp120, >780-fold enhanced neutralization by soluble CD4, and >35-fold enhanced neutralization by the antibodies found within a pool of plasmas from unrelated individuals. Enhanced neutralization sensitivity was not explained by differences in Env infectivity, Env concentration, Env shedding, or apparent differences in fusion kinetics. Furthermore, introduction of these mutations into unrelated viral Env sequences, including those from both another subtype A variant and a subtype B variant, resulted in enhanced neutralization susceptibility to gp41- and gp120-specific antibodies, and to plasma antibodies. This enhanced neutralization sensitivity exceeded 1,000-fold in several cases. Conclusions Two amino acid mutations within gp41 were identified that expose multiple discontinuous neutralization epitopes on diverse HIV-1 Env proteins. These exposed epitopes were shielded on the unmodified viral Env proteins, and several of the exposed epitopes encompass desired target regions for protective antibodies. Env proteins containing these modifications could act as a scaffold for presentation of such conserved domains, and may aid in developing methods to target antibodies to such regions., Julie Overbaugh and colleagues analyze an HIV strain with high susceptibility to antibody neutralization and identify two gp41 envelope mutations that confer this sensitivity by exposing multiple neutralization epitopes., Editors' Summary Background. In 1984 when scientists identified human immunodeficiency virus (HIV)—the cause of acquired immunodeficiency syndrome (AIDS)—many experts believed that a vaccine against HIV infection would soon be developed. Nearly 25 years later, there is still no such vaccine and with about 2.5 million new HIV infections in 2007, an effective vaccine is urgently needed to contain the AIDS epidemic. Vaccines provide protection against infectious diseases by priming the immune system to deal quickly and effectively with viruses and other pathogens. Vaccines do this by exposing the immune system to an immunogen—a fragment or harmless version of the pathogen. The immune system mounts a response against the immunogen and also “learns” from this experience so that if it is ever challenged with a virulent version of the same pathogen, it can quickly contain the threat. Many vaccines work by stimulating an antibody response. Antibodies are proteins made by the immune system that bind to molecules called antigens on the surface of pathogens. Antibodies that inactivate the invader upon binding to it are called “neutralizing” antibodies. Why Was This Study Done? Several characteristics of HIV have hampered the development of an effective vaccine. An “envelope” protein consisting of two subunits called gp120 and gp41 covers the outside of HIV. Many regions of this protein change rapidly, so the antibody response stimulated by a vaccine containing the envelope protein of one HIV variant provides little protection against other variants. However, other regions of the protein rarely change, so a vaccine that stimulates the production of antibodies to these “conserved” regions is likely to provide protection against many HIV variants. That is, it will stimulate the production of broadly neutralizing antibodies. Unfortunately, it has been difficult to find HIV vaccines that do this, because these conserved regions are often hidden from the immune system by other parts of the envelope protein. In this study, the researchers investigate the envelope protein of an HIV-1 variant they have isolated that is highly susceptible to inactivation by antibodies specific for these conserved regions. Comparing the envelope protein of this sensitive virus to closely related envelope proteins that are resistant to neutralization could identify features that might, if included in an envelope protein immunogen, produce a vaccine capable of generating broadly neutralizing antibodies. What Did the Researchers Do and Find? The researchers isolated a subtype A HIV-1 variant from a newly infected woman in Kenya that was efficiently neutralized by monoclonal antibodies (antibodies made by cells that have been cloned in the laboratory). These antibodies were specific for several different conserved regions of gp41 and gp120. The isolate was also neutralized by antibodies in blood from HIV-1-infected people. The envelope protein of the sensitive variant was the same as that of a resistant variant isolated at the same time from the woman, except for four amino acid changes in conserved regions of gp41 (proteins are made from long strings of amino acids). Using a technique called site-directed mutagenesis, the researchers introduced these amino acid changes into envelope proteins made in the laboratory and determined that just two of these changes were responsible for the neutralization sensitivity of the HIV-1 variant. The introduction of these two changes into the neutralization resistant variant and into the unrelated envelope sequences of another subtype A (common in Africa) HIV-1 variant and a subtype B HIV-1 (common in Europe and the Western Hemisphere) variant increased the sensitivity of all these viruses to antibody neutralization. What Do These Findings Mean? These findings show that two amino acid changes in gp41 of a neutralization-sensitive HIV-1 variant are responsible for the sensitivity of this variant to several neutralizing antibodies. The finding that the inclusion of these changes in the envelope protein of neutralization-resistant HIV-1 variants greatly increases their sensitivity to neutralizing antibodies indicates that the normally shielded regions of the protein are somehow made accessible to antibody by these changes. One possibility is that the amino acid changes might modify the overall shape of the envelope protein, thus exposing multiple, normally hidden regions in the HIV-1 envelope protein to antibodies. Importantly, these findings open up the possibility that the inclusion of these modifications in envelope-based immunogens might improve the ability of vaccines to generate broadly neutralizing antibodies against HIV-1. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050009. Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS HIVInSite has comprehensive information on all aspects of HIV/AIDS, including links to resources dealing with HIV vaccine development Information is available from Avert, an international AIDS charity, on all aspects of HIV and AIDS, including HIV vaccines The US Centers for Disease Control and prevention provides information on HIV/AIDS including information on its HIV vaccine unit (in English and some information in Spanish) The AIDS Vaccine Clearinghouse provides clear information about HIV vaccine science, research and product development The International AIDS Vaccine Initiative also provides straightforward information about the development of HIV vaccines

Background Plasmodium vivax invasion requires interaction between the human Duffy antigen on the surface of erythrocytes and the P. vivax Duffy binding protein (PvDBP) expressed by the parasite. Given that Duffy-negative individuals are resistant and that Duffy-negative heterozygotes show reduced susceptibility to blood-stage infection, we hypothesized that antibodies directed against region two of P. vivax Duffy binding protein (PvDBPII) would inhibit P. vivax invasion of human erythrocytes. Methods and Findings Using a recombinant region two of the P. vivax Duffy binding protein (rPvDBPII), polyclonal antibodies were generated from immunized rabbits and affinity purified from the pooled sera of 14 P. vivax–exposed Papua New Guineans. It was determined by ELISA and by flow cytometry, respectively, that both rabbit and human antibodies inhibited binding of rPvDBPII to the Duffy antigen N-terminal region and to Duffy-positive human erythrocytes. Additionally, using immunofluorescent microscopy, the antibodies were shown to attach to native PvDBP on the apical end of the P. vivax merozoite. In vitro invasion assays, using blood isolates from individuals in the Mae Sot district of Thailand, showed that addition of rabbit anti-PvDBPII Ab or serum (antibodies against, or serum containing antibodies against, region two of the Plasmodium vivax Duffy binding protein) (1:100) reduced the number of parasite invasions by up to 64%, while pooled PvDBPII antisera from P. vivax–exposed people reduced P. vivax invasion by up to 54%. Conclusions These results show, for what we believe to be the first time, that both rabbit and human antibodies directed against PvDBPII reduce invasion efficiency of wild P. vivax isolated from infected patients, and suggest that a PvDBP-based vaccine may reduce human blood-stage P. vivax infection., Christopher King and colleagues found that both rabbit and human antibodies inhibited binding of rPvDBPII to the Duffy antigen N-terminal region and to Duffy-positive human erythrocytes, suggesting that a PvDBP-based vaccine may reduce blood stage Plasmodium vivax infection., Editors' Summary Background. Malaria is a parasitic infection transmitted to people through the bite of an infected mosquito. Four different parasites cause malaria—the commonest and most widely distributed of these is Plasmodium vivax. Infections with P. vivax are rarely fatal, but they cause debilitating chills and fevers that recur every other day if untreated. Like other malaria parasites, P. vivax has a complex life cycle. Infected mosquitoes inject a form of the parasite known as sporozoites into people. The sporozoites replicate inside liver cells without causing any symptoms. Then, 8–9 d later, merozoites (another form of the parasite) are released from the liver cells and invade young red blood cells. Here, they replicate rapidly before bursting out and infecting more red blood cells. The characteristic symptoms of malaria are caused by this cyclical increase in the parasite burden. P. vivax infections are usually treated with chloroquine, but patients must also take a second drug called primaquine. This drug kills hypnozoites, a form of the parasite that hibernates in the liver and that can cause a relapse many months after the initial bout of malaria. Why Was This Study Done? P. vivax is becoming resistant to chloroquine and, although other antimalarial drugs still kill it, a vaccine that would limit the severity of P. vivax infections by blocking its ability to invade red blood cells is urgently needed. The invasion of red blood cells by P. vivax depends on an interaction between the Duffy antigen (a protein on the surface of human red blood cells) and the Duffy binding protein (PvDBP), which is expressed by merozoites. People who lack the Duffy antigen are resistant to blood-stage infections of P. vivax. Similarly, people who express half the normal amount of Duffy antigen on their red blood cells have reduced susceptibility to these infections. In this study, the researchers investigated whether antibodies (proteins made by the immune system that recognize foreign proteins) directed against PvDBP inhibit the invasion of human red blood cells by P. vivax. What Did the Researchers Do and Find? The researchers injected a fragment of PvDBP called PvDBPII into rabbits and purified the part of the blood that contains antibodies from the animals. They also isolated antibodies to PvDBPII from the blood of several Papua New Guineans who had been exposed to P. vivax. Both types of antibodies bound to PvDBPII in test tubes and to PvDBP expressed on P. vivax merozoites. Then, the researchers showed that both types of antibody inhibited the binding of PvDBPII to Duffy antigen when the antigen was in solution and when it was present on human red blood cells. Finally, to test the ability of the antibodies to inhibit red blood cell invasion by P. vivax, the researchers established short-term cultures of the parasite from blood taken from infected adults living in Thailand. Addition of the rabbit or human antibodies to these cultures inhibited parasite invasion of red blood cells by more than 50%. What Do These Findings Mean? These findings show, for what is believed to be the first time, that antibodies recognizing a fragment of PvDBP can partly inhibit the invasion of red blood cells by P. vivax merozoites. The results with the human antibodies are particularly important as they strongly suggest that a PvDBP-based vaccine might provide protection against blood-stage P. vivax infections. Whether the level of inhibition of invasion seen in this study will be sufficient to reduce the clinical severity of these infections will only become clear, however, when a vaccine is tested in people. The findings also indicate that short-term P. vivax cultures can be used to test whether antibodies that recognize other merozoite proteins also inhibit invasion. Unlike P. falciparum (the other major malarial parasite), P. vivax cannot be grown continuously in the laboratory. These short-term cultures will at last provide vaccine developers with a way to evaluate antigens as candidates for inclusion in P. vivax vaccines. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040337. MedlinePlus encyclopedia page on malaria (in English and Spanish) Information from the US Centers for Disease Control and Prevention on malaria (in English and Spanish) Vivaxmalaria, information for the malaria research community on topics related to Plasmodium vivax Information from the Malaria Vaccine Initiative about malaria and malaria vaccines, including a fact sheet on Plasmodium vivax malaria

Background Recent reports of high HIV infection rates among men who have sex with men (MSM) from Asia, Africa, Latin America, and the former Soviet Union (FSU) suggest high levels of HIV transmission among MSM in low- and middle-income countries. To investigate the global epidemic of HIV among MSM and the relationship of MSM outbreaks to general populations, we conducted a comprehensive review of HIV studies among MSM in low- and middle-income countries and performed a meta-analysis of reported MSM and reproductive-age adult HIV prevalence data. Methods and Findings A comprehensive review of the literature was conducted using systematic methodology. Data regarding HIV prevalence and total sample size was sequestered from each of the studies that met inclusion criteria and aggregate values for each country were calculated. Pooled odds ratio (OR) estimates were stratified by factors including HIV prevalence of the country, Joint United Nations Programme on HIV/AIDS (UNAIDS)–classified level of HIV epidemic, geographic region, and whether or not injection drug users (IDUs) played a significant role in given epidemic. Pooled ORs were stratified by prevalence level; very low-prevalence countries had an overall MSM OR of 58.4 (95% CI 56.3–60.6); low-prevalence countries, 14.4 (95% CI 13.8–14.9); and medium- to high-prevalence countries, 9.6 (95% CI 9.0–10.2). Significant differences in ORs for HIV infection among MSM in were seen when comparing low- and middle-income countries; low-income countries had an OR of 7.8 (95% CI 7.2–8.4), whereas middle-income countries had an OR of 23.4 (95% CI 22.8–24.0). Stratifying the pooled ORs by whether the country had a substantial component of IDU spread resulted in an OR of 12.8 (95% CI 12.3–13.4) in countries where IDU transmission was prevalent, and 24.4 (95% CI 23.7–25.2) where it was not. By region, the OR for MSM in the Americas was 33.3 (95% CI 32.3–34.2); 18.7 (95% CI 17.7–19.7) for Asia; 3.8 (95% CI 3.3–4.3) for Africa; and 1.3 (95% CI 1.1–1.6) for the low- and middle-income countries of Europe. Conclusions MSM have a markedly greater risk of being infected with HIV compared with general population samples from low- and middle-income countries in the Americas, Asia, and Africa. ORs for HIV infection in MSM are elevated across prevalence levels by country and decrease as general population prevalence increases, but remain 9-fold higher in medium–high prevalence settings. MSM from low- and middle-income countries are in urgent need of prevention and care, and appear to be both understudied and underserved., From a systematic review, Chris Beyrer and colleagues conclude that men who have sex with men in the Americas, Asia, and Africa have a markedly greater risk of being HIV-infected than does the general population., Editors' Summary Background. AIDS (acquired immunodeficiency syndrome) first emerged in the early 1980s among gay men living in New York and California. But, as the disease rapidly spread around the world, it became clear that AIDS also affected heterosexual men and women. Now, a quarter of a century later, 40 million people are infected with human immunodeficiency virus (HIV), the organism that causes AIDS. HIV is most often spread by having unprotected sex with an infected partner and in sub-Saharan Africa, the region most badly hit by HIV/AIDS, heterosexual transmission predominates. However, globally, 5%–10% of all HIV infections are thought to be in men who have sex with men (MSM, a term that encompasses gay, bisexual, transgendered, and heterosexual men who sometimes have sex with men), and in several high-income countries, including the US, male-to-male sexual contact remains the most important HIV transmission route. Why Was This Study Done? In the US, the MSM population is visible and there is considerable awareness about the risks of HIV transmission associated with sex between men. In many other countries, MSM are much less visible. They remain invisible because they fear discrimination, stigmatization (being considered socially unacceptable), or arrest—sex between men is illegal in 85 countries. Consequently, MSM are often under-represented in HIV surveillance systems and in prevention and care programs. If the AIDS epidemic is going to be halted, much more needs to be known about HIV prevalence (the proportion of the population that is infected) among MSM. In this study, the researchers have done a systematic review (a type of research where the results of existing studies are brought together) on published reports of HIV prevalence among MSM in low- and middle-income countries to get a better picture of the global epidemic of HIV in this population. What Did the Researchers Do and Find? The researchers found 83 published studies that reported HIV prevalence in 38 low- and middle-income countries in Asia, Africa, the Americas, and Eastern Europe. When the results were pooled—in what statisticians call a meta-analysis—MSM were found to have a 19.3-times greater chance of being infected with HIV than the general population. This is described as a pooled odds ratio (OR) of 19.3. The researchers also did several subgroup analyses where they asked whether factors such as injection drug use (another risk factor for HIV transmission), per capita income, geographical region, or the HIV prevalence in the general population were associated with differential risk (increase in odds) of HIV infection compared to the general population. They found, for example, that in countries where the prevalence of HIV in the general population was very low (less than 1 adult in 1,000 infected) the pooled OR for MSM compared to the general population was 58.4; where it was high (more than 1 adult in 20 infected), the pooled OR for MSM was 9.6. What Do These Findings Mean? These findings indicate that MSM living in low- to middle-income countries have a greater risk of HIV infection than the general populations of these countries. The subgroup analyses indicate that the high HIV prevalence among MSM is not limited to any one region or income level or to countries with any specific HIV prevalence or injection drug use level. Although the small number and design of the studies included in the meta-analysis may affect the numerical accuracy of these findings, the clear trend toward a higher HIV prevalence of among MSM suggests that HIV surveillance efforts should be expanded to include MSM in those countries where they are currently ignored. Efforts should also be made to include MSM in HIV prevention programs and to improve the efficacy of these programs by investigating the cultural, behavioral, social, and public policy factors that underlie the high HIV prevalence among MSM. By increasing surveillance, research, and prevention among MSM in low- to middle-income countries, it should be possible to curb HIV transmission in this marginalized population and reduce the global burden of HIV. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040339. The International Lesbian and Gay Association provides a world legal map on legislation affecting lesbian, gay, bisexual, and transgendered people The International Gay and Lesbian Human Rights Commission provides a page called Off the Map: How HIV/AIDS Programming is Failing Same-Sex Practicing People in Africa The American Foundation for AIDS Research (amfAR) has launched their MSM initiative, which is focused on providing support to front-line community groups working on providing services and doing research focused on HIV among MSM in lower income-settings Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS HIV InSite has comprehensive information on all aspects of HIV/AIDS, including a list of organizations that provide information for gay men and MSM Information is available from Avert, an international AIDS charity, on HIV, AIDS, and men who have sex with men The US Centers for Disease Control and Prevention provides information on HIV/AIDS and on HIV/AIDS among men who have sex with men (in English and Spanish)

BACKGROUND:Plasmodium vivax invasion requires interaction between the human Duffy antigen on the surface of erythrocytes and the P. vivax Duffy binding protein (PvDBP) expressed by the parasite. Given that Duffy-negative individuals are resistant and that Duffy-negative heterozygotes show reduced susceptibility to blood-stage infection, we hypothesized that antibodies directed against region two of P. vivax Duffy binding protein (PvDBPII) would inhibit P. vivax invasion of human erythrocytes. METHODS AND FINDINGS:Using a recombinant region two of the P. vivax Duffy binding protein (rPvDBPII), polyclonal antibodies were generated from immunized rabbits and affinity purified from the pooled sera of 14 P. vivax-exposed Papua New Guineans. It was determined by ELISA and by flow cytometry, respectively, that both rabbit and human antibodies inhibited binding of rPvDBPII to the Duffy antigen N-terminal region and to Duffy-positive human erythrocytes. Additionally, using immunofluorescent microscopy, the antibodies were shown to attach to native PvDBP on the apical end of the P. vivax merozoite. In vitro invasion assays, using blood isolates from individuals in the Mae Sot district of Thailand, showed that addition of rabbit anti-PvDBPII Ab or serum (antibodies against, or serum containing antibodies against, region two of the Plasmodium vivax Duffy binding protein) (1:100) reduced the number of parasite invasions by up to 64%, while pooled PvDBPII antisera from P. vivax-exposed people reduced P. vivax invasion by up to 54%. CONCLUSIONS:These results show, for what we believe to be the first time, that both rabbit and human antibodies directed against PvDBPII reduce invasion efficiency of wild P. vivax isolated from infected patients, and suggest that a PvDBP-based vaccine may reduce human blood-stage P. vivax infection.

Through its impact on worker productivity, premature disability, and death, Chagas disease accounts for 670,000 disability-adjusted life years per annum [1]. This makes it the most important parasitic disease of the Americas. It is both a disease of poverty (Figures 1 and ​and2)2) and, like other neglected tropical diseases, also “poverty promoting” [2]. Traditionally confined to Latin America, Chagas disease is becoming an important health issue in the United States and Europe. First, due to the continuous influx of immigrants from disease-endemic countries in Latin America, a proportion of whom are infected with Trypanosoma cruzi, an increasing number of infected subjects are seen in clinical practice, whether, for example, through routine screening of US blood and organ banks [3] or physicians' offices in Europe [4]. The appearance of T. cruzi in US blood banks led to the implementation of the first Food and Drug Administration–approved diagnostic blood screening test for Chagas disease earlier this year [5]. Second, an increasing number of autochthonous Chagas disease cases have been reported in the US [6,7], which may mirror the increased reporting of T. cruzi infection in domestic animals and wildlife. Recognizing that Chagas disease can no longer be considered an “exotic” disease in the US, the American Society of Tropical Medicine and Hygiene held a clinical course in Chagas disease prior to its 2007 annual meeting (http://www.astmh.org/meetings/premeeting.cfm#clinical). Figure 1 Chagas Disease Is Closely Linked to Poverty and Socioeconomic Development, and Poor Housing In Particular Figure 2 Interior of House Showing the Type of Wall Construction Often Found in Households in Many Endemic Areas Despite estimates of up to 15 million existing cases and 50,000–200,000 new infections per year, funding for research, prevention, and control has been limited, and therapeutic options remain unsatisfactory. Consequently, several editorials and perspectives have recently drawn attention to Chagas disease and T. cruzi [8–10]. While these papers highlighted the impact of this disease on public health in the Americas, and rightly pointed out that major achievements have been made in its control, they failed to emphasize several key challenges that are currently undermining these achievements and that must be urgently addressed in order to move to the next stage: ensuring the long-term and sustainable control of this devastating disease.

Background For more than a decade, most parts of Somalia have not been under the control of any type of government. This “failure of state” is complete in the central and southern regions and most apparent in Mogadishu, which had been for a long period in the hands of warlords deploying their private militias in a battle for resources. In contrast, the northern part of Somalia has had relatively stable control under regional administrations, which are, however, not internationally recognized. The present study provides information about drug abuse among active security personnel and militia with an emphasis on regional differences in relation to the lack of central governmental control—to our knowledge the first account on this topic. Methods and Findings Trained local interviewers conducted a total of 8,723 interviews of armed personnel in seven convenience samples in different regions of Somalia; 587 (6.3%) respondents discontinued the interview and 12 (0.001%) were excluded for other reasons. We assessed basic sociodemographic information, self-reported khat use, and how respondents perceived the use of khat, cannabis (which includes both hashish and marijuana), psychoactive tablets (e.g., benzodiazepines), alcohol, solvents, and hemp seeds in their units. The cautious interpretation of our data suggest that sociodemographic characteristics and drug use among military personnel differ substantially between northern and southern/central Somalia. In total, 36.4% (99% confidence interval [CI] 19.3%–57.7%) of respondents reported khat use in the week before the interview, whereas in some regions of southern/central Somalia khat use, especially excessive use, was reported more frequently. Self-reported khat use differed substantially from the perceived use in units. According to the perception of respondents, the most frequent form of drug use is khat chewing (on average, 70.1% in previous week, 99% CI 63.6%–76.5%), followed by smoking cannabis (10.7%, 99% CI 0%–30.4%), ingesting psychoactive tablets (8.5%, 99% CI 0%–24.4%), drinking alcohol (5.3%, 99% CI 0%–13.8%), inhaling solvents (1.8%, 99% CI 0%–5.1%), and eating hemp seeds (0.6%, 99% CI 0%–2.0%). Perceived use of khat differs little between northern and southern Somalia, but perceived use of other drugs reaches alarmingly high levels in some regions of the south, especially related to smoking cannabis and using psychoactive tablets. Conclusions Our data suggest that drug use has quantitatively and qualitatively changed over the course of conflicts in southern Somalia, as current patterns are in contrast to traditional use. Although future studies using random sampling methods need to confirm our results, we hypothesize that drug-related problems of armed staff and other vulnerable groups in southern Somalia has reached proportions formerly unknown to the country, especially as we believe that any biases in our data would lead to an underestimation of actual drug use. We recommend that future disarmament, demobilization, and reintegration (DDR) programs need to be prepared to deal with significant drug-related problems in Somalia., Having interviewed military personnel in Somali, Michael Odenwald and colleagues conclude that drug-related problems, mainly relating to the use of khat, have reached proportions formerly unknown to the country., Editors' Summary Background. Somalia—a country in eastern Africa—has been torn apart by civil war over the past few decades. Fighting among clans and warlords has caused the near-complete breakdown of state control in the central and southern regions of the country (including the capital, Mogadishu) although independent administrations provide some governmental control in the northern regions of Somaliland and Puntland. Efforts to establish a transitional federal government have largely failed and, to date, it has been impossible to initiate a nationwide disarmament, demobilization, and reintegration (DDR) program in Somalia for ex-combatants, a key step in the transition from war to peace. As in other war-torn countries, the social and economic reintegration of ex-combatants into civil society in Somalia is likely to be difficult. However, without effective reintegration, ex-combatants may take up arms again because they have no means of economic support or become disaffected and seek to destabilize the peace. Why Was This Study Done? One risk factor for poor adjustment to civilian life among ex-combatants is substance abuse. Many ex-combatants use drugs to help them deal with traumatic war-related memories, but unrecognized drug abuse can hinder reintegration, increase criminality, and threaten the peace-building process. Most studies on substance abuse and treatment of drug-related problems of former combatants have been done in Western countries. Very little is known about how many ex-combatants abuse drugs and the types of drugs they abuse in postconflict regions in Africa. This information is needed if DDR programs are to be effective. In this study, therefore, the researchers have investigated drug use among “convenience” samples of combatants in seven regions of Somalia. Convenience samples are groups of people chosen to participate in a study because they were available rather than groups chosen randomly from the whole population. What Did the Researchers Do and Find? Trained interviewers asked more than 8,000 military personnel about their own recent use of khat (chewing khat leaves releases an amphetamine-like stimulant), a legally traded drug in Somalia, where its use has long been commonplace. The interviewers also asked the respondents how much they thought others in their military personnel unit used khat and other drugs such as cannabis, psychoactive drugs (tranquilizers and other drugs that change mood, behavior, and thinking), solvents, alcohol, and hemp seeds. (Note that the researchers relied on perceived drug use; alcohol is illegal in Somalia, which is a Muslim country, and the use of drugs other than khat is not generally acknowledged.) Over the whole of Somalia, one-third of respondents said they had used khat recently. The highest levels of self-reported use were in southern/central Somalia, where up to two-thirds of combatants used it. More respondents in southern/central Somalia reported using an excessive amount of khat (more than two “bundles” of khat per day for one week) and having sleepless nights (a side-effect of khat) than in northern Somalia. The overall perceived use of khat (two-thirds of combatants) was higher than the self-reported use but similar in northern and southern/central regions. Finally, the perceived use of other drugs was highest in the southern/central regions. What Do These Findings Mean? The use of convenience samples (which may not be representative of the whole population) and other aspects of this study mean that the numerical values of these findings may be inaccurate. For example, the levels of self-reported khat use may be underestimates because drug-using combatants may have been undersampled or not all combatants may have responded honestly. Nevertheless, these findings confirm that khat is the most commonly consumed drug among combatants and reveal a large increase in the number of people using it in southern/central Somalia since the conflict began (only one in five adult males used khat in these regions in 1980). They also reveal that more khat is being consumed by some individuals than previously, particularly in the southern/central regions, and uncover a worrying increase in the perceived use of other drugs, again mainly in the southern/central regions. These changes in the traditional patterns of drug use in Somalia, if confirmed in studies that use random sampling methods, suggest that future DDR programs in Somalia will need to be prepared to deal with major drug-related problems and that drug use among the general population might have reached dimensions formerly unknown to the country. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040341. Information about Somalia is available from the US Department of State, the United Nations, and Swiss Peace, a peace research institute The US Council on Foreign Relations, the Beyond Intractability Knowledge Base Project (based at the University of Colorado), and the UN DDR Resource Centre provide general information on DDR programs The Multi-Country Demobilization and Reintegration program provides additional information about ongoing DDR programs in other parts of Africa (in English and French) DrugScope (a UK charity) provides information about khat The US National Drug Intelligence Center provides information about khat in the US The UK Advisory Council on the Misuse of Drugs provides an assessment of the risk of khat to individuals and communities in the UK The Vivo Foundation supports programs that relieve the trauma of stress, including PTSD

Background In Africa, women tested for HIV during antenatal care are counselled to share with their partner their HIV test result and to encourage partners to undertake HIV testing. We investigate, among women tested for HIV within a prevention of mother-to-child transmission of HIV (PMTCT) programme, the key moments for disclosure of their own HIV status to their partner and the impact on partner HIV testing. Methods and Findings Within the Ditrame Plus PMTCT project in Abidjan, 546 HIV-positive and 393 HIV-negative women were tested during pregnancy and followed-up for two years after delivery. Circumstances, frequency, and determinants of disclosure to the male partner were estimated according to HIV status. The determinants of partner HIV testing were identified according to women's HIV status. During the two-year follow-up, disclosure to the partner was reported by 96.7% of the HIV-negative women, compared to 46.2% of HIV-positive women (χ2 = 265.2, degrees of freedom [df] = 1, p < 0.001). Among HIV-infected women, privileged circumstances for disclosure were just before delivery, during early weaning (at 4 mo to prevent HIV postnatal transmission), or upon resumption of sexual activity. Formula feeding by HIV-infected women increased the probability of disclosure (adjusted odds ratio 1.54, 95% confidence interval 1.04–2.27, Wald test = 4.649, df = 1, p = 0.031), whereas household factors such as having a co-spouse or living with family reduced the probability of disclosure. The proportion of male partners tested for HIV was 23.1% among HIV-positive women and 14.8% among HIV-negative women (χ2 = 10.04, df = 1, p = 0.002). Partners of HIV-positive women who were informed of their wife's HIV status were more likely to undertake HIV testing than those not informed (37.7% versus 10.5%, χ2 = 56.36, df = 1, p < 0.001). Conclusions In PMTCT programmes, specific psychosocial counselling and support should be provided to women during the key moments of disclosure of HIV status to their partners (end of pregnancy, weaning, and resumption of sexual activity). This support could contribute to improving women's adherence to the advice given to prevent postnatal and sexual HIV transmission., In a mother-to-child HIV prevention program in Côte d'Ivoire, Annabel Desgrées-du-Loû and colleagues identify three junctures at which women tend to disclose their HIV status to partners., Editors' Summary Background. Since the first reported case of AIDS (acquired immunodeficiency syndrome) in 1981, the number of people infected with the human immunodeficiency virus (HIV), which causes AIDS, has risen steadily. By the end of 2006, nearly 40 million people were infected, 25 million of them in sub-Saharan Africa. HIV is most often spread by having unprotected sex with an infected partner. In Africa, most sexual transmission of HIV is between partners in stable relationships—many such couples do not adopt measures that prevent viral transmission, such as knowing the HIV status of both partners and using condoms if one partner is HIV-positive. HIV can also pass from a mother to her baby during pregnancy, labor, or delivery, or through breastfeeding. Mother-to-child transmission (MTCT) of HIV can be reduced by giving anti-HIV drugs to the mother during pregnancy and labor and to her newborn baby, and by avoiding breastfeeding or weaning the baby early. Why Was This Study Done? Many African countries have programs for prevention of MTCT (PMTCT) that offer pregnant women prenatal HIV counseling and testing. As a result, women are often the first member of a stable relationship to know their HIV status. PMTCT programs advise women to disclose their HIV test result to their partner and to encourage him to have an HIV test. But for many women, particularly those who are HIV-positive, talking to their partner about HIV/AIDS is hard because of fears of rejection (which could mean loss of housing and food) or accusations of infidelity. Knowing more about when women disclose their HIV status and what makes them decide to do so would help the people running PMTCT programs to support women during the difficult process of disclosure. In this study, the researchers have investigated when and why women participating in a PMTCT research project in Abidjan (Côte d'Ivoire) told their partner about their HIV status and the impact this disclosure had on their partner's uptake of HIV testing. What Did the Researchers Do and Find? At regular follow-up visits, the researchers asked women in the Abidjan PMTCT project whether they had told their partners their HIV status and whether they were breast-feeding or had resumed sexual activity. Nearly all the women who tested negative for HIV, but slightly fewer than half of the HIV-positive (infected) women had told their partner about their HIV status by two years after childbirth. Two-thirds of the HIV-positive women who disclosed their status did so before delivery. Other key times for disclosure were at early weaning (4 months after birth) for women who breast-fed their babies, and when sexual activity resumed. HIV-positive women who bottle fed their babies from birth were more likely to tell their partners of their status than women who breast-fed. Factors that prevented women disclosing their HIV status included living in a polygamous relationship or living separately from their partners. Finally, the researchers report that the partners of HIV-positive women who disclosed their HIV status were about three times more likely to take an HIV test than the partners of HIV-positive women who did not disclose. What Do These Findings Mean? These findings identify three key times when women who have had an HIV test during pregnancy are likely to disclose their HIV status to their partner. The main one is before delivery and relates, in part, to how the mother plans to feed her baby. To bottle feed in Abidjan, women need considerable support from their partners and this may be the impetus for disclosing their HIV status. Disclosure at early weaning may reflect the woman's need to enlist her partner's support for this unusual decision—the normal time for weaning in Abidjan is 17 months. Finally, disclosure when sexual activity resumes may be necessary so that the woman can explain why she wants to use condoms. Although these findings need confirmation in other settings, targeting counseling and support within PMTCT programs to these key moments might help HIV-positive women to tell their partners about their status. This, hopefully, would help to reduce sexual transmission of HIV within stable relationships in sub-Saharan Africa. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040342. Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS and on HIV infection in women HIV InSite has comprehensive information on all aspects of HIV/AIDS Women Children and HIV provides extensive information on prevention of mother-to-child transmission of HIV in developing countries Information is available from Avert, an international AIDS charity, on HIV and AIDS in Africa and on HIV and AIDS prevention AIDSinfo, a service of the US Department of Health and Human Services provideshealth information for HIV-positive pregnant women (in English and Spanish)

The authors describe CMV retinitis in resource-poor settings and suggest possibilities for management.

The author discusses two studies that report important methodological advances in determining cause of death, which is crucial for health planning and prioritization.