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In 2014, panel physicians from the International Organization for Migration (IOM), who conduct Department of State-required predeparture examinations for U.S.-bound refugees at resettlement sites in Uganda, noticed an unusually high number of Congolese refugees with enlarged spleens, or splenomegaly. Many conditions can cause splenomegaly, such as various infections, liver disease, and cancer. Splenomegaly can result in hematologic disturbances and abdominal pain and can increase the risk for splenic rupture from blunt trauma, resulting in life-threatening internal bleeding. On CDC's advice, panel physicians implemented an enhanced surveillance and treatment protocol that included screening for malaria (through thick and thin smears and rapid diagnostic testing), schistosomiasis, and several other conditions; treatment of any condition identified as potentially associated with splenomegaly; and empiric treatment for the most likely etiologies, including malaria and schistosomiasis. CDC recommended further treatment for malaria with primaquine after arrival, after glucose-6-phosphate dehydrogenase testing, to target liver-stage parasites. Despite this recommended treatment protocol, 35 of 64 patients with available follow-up records had splenomegaly that persisted beyond 6 months after resettlement. Among 85 patients who were diagnosed with splenomegaly through abdominal palpation or ultrasound at any point after resettlement, 53 had some hematologic abnormality (leukopenia, anemia, or thrombocytopenia), 16 had evidence of current or recent malaria infection, and eight had evidence of schistosomiasis. Even though primaquine was provided to a minority of patients in this cohort, it should be provided to all eligible patients with persistent splenomegaly, and repeated antischistosomal therapy should be provided to patients with evidence of current or recent schistosomiasis. Given substantial evidence of familial clustering of cases, family members of patients with known splenomegaly should be proactively screened for this condition., Competing Interests: All authors have completed and submitted the ICMJE form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

Background: The response to antimalarial treatment is assessed using serial microscopy. New techniques for accurate measurement of the Plasmodium falciparum histidine-rich protein 2 (HRP2) antigen have allowed for monitoring of the antigen concentration over time, offering a potential alternative for assessing treatment response., Methods: Posttreatment HRP2 concentrations were measured in samples obtained longitudinally from 537 individuals with P. falciparum malaria who were participating in efficacy trials in Angola, Tanzania, and Senegal. The HRP2 half-life was estimated using a first-order kinetics clearance model. The association between the HRP2 concentration 3 days after treatment and recrudescence of infection was assessed., Results: Despite substantial variation in HRP2 concentrations among participants at baseline, concentrations consistently showed a first-order exponential decline. The median half-life of HRP2 was estimated to be 4.5 days (interquartile range [IQR], 3.3-6.6 days) in Angola, 4.7 days (IQR, 4.0-5.9 days) in Tanzania, and 3.0 days (IQR, 2.1-4.5 days) in Senegal. The day 3 HRP2 concentration was predictive of eventual recrudescence, with an area under the receiver operating characteristic curve of 0.86 (95% confidence interval, .73-.99)., Conclusions: Consistent HRP2 clearance dynamics following successful antimalarial treatment imply a common underlying mechanism of biological clearance. Patients who ultimately did not respond to treatment did not exhibit this same pattern of clearance, even in the absence of other indications of inadequate response to treatment., (Published by Oxford University Press for the Infectious Diseases Society of America 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Background: Recent efforts in malaria control have resulted in great gains in reducing the burden of Plasmodium falciparum, but P. vivax has been more refractory. Its ability to form dormant liver stages confounds control and elimination efforts. To compare the efficacy and safety of primaquine regimens for radical cure, we undertook a randomized controlled trial in Ethiopia., Methods and Findings: Patients with normal glucose-6-phosphate dehydrogenase status with symptomatic P. vivax mono-infection were enrolled and randomly assigned to receive either chloroquine (CQ) or artemether-lumefantrine (AL), alone or in combination with 14 d of semi-supervised primaquine (PQ) (3.5 mg/kg total). A total of 398 patients (n = 104 in the CQ arm, n = 100 in the AL arm, n = 102 in the CQ+PQ arm, and n = 92 in the AL+PQ arm) were followed for 1 y, and recurrent episodes were treated with the same treatment allocated at enrolment. The primary endpoints were the risk of P. vivax recurrence at day 28 and at day 42. The risk of recurrent P. vivax infection at day 28 was 4.0% (95% CI 1.5%-10.4%) after CQ treatment and 0% (95% CI 0%-4.0%) after CQ+PQ. The corresponding risks were 12.0% (95% CI 6.8%-20.6%) following AL alone and 2.3% (95% CI 0.6%-9.0%) following AL+PQ. On day 42, the risk was 18.7% (95% CI 12.2%-28.0%) after CQ, 1.2% (95% CI 0.2%-8.0%) after CQ+PQ, 29.9% (95% CI 21.6%-40.5%) after AL, and 5.9% (95% CI 2.4%-13.5%) after AL+PQ (overall p < 0.001). In those not prescribed PQ, the risk of recurrence by day 42 appeared greater following AL treatment than CQ treatment (HR = 1.8 [95% CI 1.0-3.2]; p = 0.059). At the end of follow-up, the incidence rate of P. vivax was 2.2 episodes/person-year for patients treated with CQ compared to 0.4 for patients treated with CQ+PQ (rate ratio: 5.1 [95% CI 2.9-9.1]; p < 0.001) and 2.3 episodes/person-year for AL compared to 0.5 for AL+PQ (rate ratio: 6.4 [95% CI 3.6-11.3]; p < 0.001). There was no difference in the occurrence of adverse events between treatment arms. The main limitations of the study were the early termination of the trial and the omission of haemoglobin measurement after day 42, resulting in an inability to estimate the cumulative risk of anaemia., Conclusions: Despite evidence of CQ-resistant P. vivax, the risk of recurrence in this study was greater following treatment with AL unless it was combined with a supervised course of PQ. PQ combined with either CQ or AL was well tolerated and reduced recurrence of vivax malaria by 5-fold at 1 y., Trial Registration: ClinicalTrials.gov NCT01680406.

Background: Insecticide-treated bednets (ITNs) are effective in preventing malaria where vectors primarily bite indoors and late at night, but their effectiveness is uncertain where vectors bite outdoors and earlier in the evening. We studied the effectiveness of ITNs following a mass distribution in Haiti from May to September, 2012, where the Anopheles albimanus vector bites primarily outdoors and often when people are awake., Methods: In this case-control study, we enrolled febrile patients presenting to outpatient departments at 17 health facilities throughout Haiti from Sept 4, 2012, to Feb 27, 2014, who were tested with malaria rapid diagnostic tests (RDTs), and administered questionnaires on ITN use and other risk factors. Cases were defined by positive RDT and controls were febrile patients from the same clinic with a negative RDT. Our primary analysis retrospectively matched cases and controls by age, sex, location, and date, and used conditional logistic regression on the matched sample. A sensitivity analysis used propensity scores to match patients on ITN use propensity and analyse malaria among ITN users and non-users. Additional ITN bioefficacy and entomological data were collected., Findings: We enrolled 9317 patients, including 378 (4%) RDT-positive cases. 1202 (13%) patients reported ITN use. Post-hoc matching of cases and controls yielded 362 cases and 1201 matched controls, 19% (333) of whom reported consistent campaign net use. After using propensity scores to match on consistent campaign ITN use, 2298 patients, including 138 (7%) RDT-positive cases, were included: 1149 consistent campaign ITN users and 1149 non-consistent campaign ITN users. Both analyses revealed that ITNs did not significantly protect against clinical malaria (odds ratio [OR]=0·95, 95% CI 0·68-1·32, p=0·745 for case-control analysis; OR=0·95, 95% CI 0·45-1·97, p=0·884 for propensity score analysis). ITN and entomological data indicated good ITN physical integrity and bioefficacy, and no permethrin resistance among local mosquitoes., Interpretation: We found no evidence that mass ITN campaigns reduce clinical malaria in this observational study in Haiti; alternative malaria control strategies should be prioritised., Funding: The Global Fund to Fight AIDS, Tuberculosis, and Malaria, and the US-based Centers for Disease Control and Prevention (CDC)., (Copyright © 2017 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND license. Published by Elsevier Ltd.. All rights reserved.)

Infections with the malaria parasite Plasmodium falciparum typically comprise multiple strains, especially in high-transmission areas where infectious mosquito bites occur frequently. However, little is known about the dynamics of mixed-strain infections, particularly whether strains sharing a host compete or grow independently. Competition between drug-sensitive and drug-resistant strains, if it occurs, could be a crucial determinant of the spread of resistance. We analysed 1341 P. falciparum infections in children from Angola, Ghana and Tanzania and found compelling evidence for competition in mixed-strain infections: overall parasite density did not increase with additional strains, and densities of individual chloroquine-sensitive (CQS) and chloroquine-resistant (CQR) strains were reduced in the presence of competitors. We also found that CQR strains exhibited low densities compared with CQS strains (in the absence of chloroquine), which may underlie observed declines of chloroquine resistance in many countries following retirement of chloroquine as a first-line therapy. Our observations support a key role for within-host competition in the evolution of drug-resistant malaria. Malaria control and resistance-management efforts in high-transmission regions may be significantly aided or hindered by the effects of competition in mixed-strain infections. Consideration of within-host dynamics may spur development of novel strategies to minimize resistance while maximizing the benefits of control measures., (© 2016 The Author(s).)

Background: Quinidine gluconate, the only U.S. Food and Drug Administration-approved treatment for life-threatening malaria in the United States, has a problematic safety profile and is often unavailable in hospitals., Objective: To assess the safety and clinical benefit of intravenous artesunate as an alternative to quinidine., Design: Retrospective case series., Setting: U.S. hospitals., Patients: 102 patients aged 1 to 72 years (90% adults; 61% men) with severe and complicated malaria. Patients received 4 weight-based doses of intravenous artesunate (2.4 mg/kg) under a treatment protocol implemented by the Centers for Disease Control and Prevention between January 2007 and December 2010. At baseline, 35% had evidence of cerebral malaria, and 17% had severe hepatic impairment. Eligibility required the presence of microscopically confirmed malaria, need for intravenous treatment, and an impediment to quinidine., Measurements: Clinical and laboratory data from each patient's hospital records were abstracted retrospectively, including information from baseline through a maximum 7-day follow-up, and presented before a physician committee to evaluate safety and clinical benefit outcomes., Results: 7 patients died (mortality rate, 6.9%). The most frequent adverse events were anemia (65%) and elevated hepatic enzyme levels (49%). All deaths and most adverse events were attributed to the severity of malaria. Patients' symptoms generally improved or resolved within 3 days, and the median time to discharge from the intensive care unit was 4 days, even for patients with severe liver disease or cerebral malaria. More than 100 concomitant medications were used, with no documented drug-drug interactions., Limitation: Potential late-presenting safety issues might occur outside the 7-day follow-up., Conclusion: Artesunate was a safe and clinically beneficial alternative to quinidine.

Background: In vivo efficacy assessments of antimalarials are essential for ensuring effective case management. In Ethiopia, chloroquine (CQ) without primaquine is the first-line treatment for Plasmodium vivax in malarious areas, but artemether-lumefantrine (AL) is also commonly used., Methods and Findings: In 2009, we conducted a 42-day efficacy study of AL or CQ for P. vivax in Oromia Regional State, Ethiopia. Individuals with P. vivax monoinfection were enrolled. Primary endpoint was day 28 cure rate. In patients with recurrent parasitemia, drug level and genotyping using microsatellite markers were assessed. Using survival analysis, uncorrected patient cure rates at day 28 were 75.7% (95% confidence interval (CI) 66.8-82.5) for AL and 90.8% (95% CI 83.6-94.9) for CQ. During the 42 days of follow-up, 41.6% (47/113) of patients in the AL arm and 31.8% (34/107) in the CQ arm presented with recurrent P. vivax infection, with the median number of days to recurrence of 28 compared to 35 days in the AL and CQ arm, respectively. Using microsatellite markers to reclassify recurrent parasitemias with a different genotype as non-treatment failures, day 28 cure rates were genotype adjusted to 91.1% (95% CI 84.1-95.1) for AL and to 97.2% (91.6-99.1) for CQ. Three patients (2.8%) with recurrent parasitemia by day 28 in the CQ arm were noted to have drug levels above 100 ng/ml., Conclusions: In the short term, both AL and CQ were effective and well-tolerated for P. vivax malaria, but high rates of recurrent parasitemia were noted with both drugs. CQ provided longer post-treatment prophylaxis than AL, resulting in delayed recurrence of parasitemia. Although the current policy of species-specific treatment can be maintained for Ethiopia, the co-administration of primaquine for treatment of P. vivax malaria needs to be urgently considered to prevent relapse infections., Trial Registration: ClinicalTrials.gov NCT01052584.

Problem/condition: Malaria in humans is caused by intraerythrocytic protozoa of the genus Plasmodium. These parasites are transmitted by the bite of an infective female Anopheles mosquito. The majority of malaria infections in the United States occur among persons who have traveled to areas with ongoing malaria transmission. In the United States, cases can occur through exposure to infected blood products, congenital transmission, or local mosquito-borne transmission. Malaria surveillance is conducted to identify episodes of local transmission and to guide prevention recommendations for travelers., Period Covered: This report summarizes cases in persons with onset of illness in 2010 and summarizes trends during previous years., Description of System: Malaria cases diagnosed by blood film, polymerase chain reaction, or rapid diagnostic tests are mandated to be reported to local and state health departments by health-care providers or laboratory staff. Case investigations are conducted by local and state health departments, and reports are transmitted to CDC through the National Malaria Surveillance System (NMSS), National Notifiable Diseases Surveillance System (NNDSS), or direct CDC consults. Data from these reporting systems serve as the basis for this report., Results: CDC received 1,691 reported cases of malaria, including 1,688 cases classified as imported, one transfusion-related case, and two cryptic cases, with an onset of symptoms in 2010 among persons in the United States. The total number of cases represents an increase of 14% from the 1,484 cases reported for 2009. Plasmodium falciparum, P. vivax, P. malariae, and P. ovale were identified in 58%, 19%, 2%, and 2% of cases, respectively. Thirteen patients were infected by two or more species. The infecting species was unreported or undetermined in 18% of cases. Among the 898 cases in U.S. civilians for whom information on chemoprophylaxis use and travel area was known, 45 (5%) reported that they had followed and adhered to a chemoprophylactic drug regimen recommended by CDC for the areas to which they had traveled. Forty-one cases were reported in pregnant women, among whom only two (5%) adhered to chemoprophylaxis. Among all reported cases, 176 (10%) were classified as severe infections, of which nine were fatal., Interpretation: The number of cases reported in 2010 marked the largest number of cases reported since 1980. Despite the apparent progress in reducing the global burden of malaria, many areas remain malaria endemic and the use of appropriate prevention measures by travelers is still inadequate., Public Health Actions: Travelers visiting friends and relatives (VFR) continue to be a difficult population to reach with effective malaria prevention strategies. Evidence-based prevention strategies that effectively target VFR travelers need to be developed and implemented to have a substantial impact on the numbers of imported malaria cases in the United States. A large number of pregnant travelers diagnosed with malaria did not take any chemoprophylaxis. Pregnant women traveling to areas in which malaria is endemic are at higher risk for severe malaria and must use appropriate malaria prevention strategies including chemoprophylaxis. Malaria prevention recommendations are available online (http://www.cdc.gov/malaria/travelers/drugs.html). Malaria infections can be fatal if not diagnosed and treated promptly with antimalarial medications appropriate for the patient's age and medical history, the likely country of malaria acquisition, and previous use of antimalarial chemoprophylaxis. Clinicians should consult the CDC Guidelines for Treatment of Malaria and contact the CDC's Malaria Hotline for case management advice, when needed. Malaria treatment recommendations can be obtained online (http://www.cdc.gov/malaria/diagnosis&#95;treatment) or by calling the Malaria Hotline (770-488-7788 or toll-free at 855-856-4713).

Background: In 2007, Malawi replaced the first-line medication for uncomplicated malaria, sulfadoxine-pyrimethamine-a single-dose regimen-with artemether-lumefantrine (AL)-a 6-dose, 3-day regimen. Because of concerns about the complex dosing schedule, we assessed patient adherence to AL 2 years after routine implementation., Methods: Adults and children with uncomplicated malaria were recruited at 3 health centers. We conducted both pill counts and in-home interviews on medication consumption 72 hours after patients received AL. Complete adherence was defined as correctly taking all 6 AL doses, as assessed by pill count and dose recall. We used logistic regression to identify factors associated with complete adherence., Results: Of 386 patients, 65% were completely adherent. Patients were significantly more likely to be completely adherent if they received their first dose of AL as directly observed therapy at the health center (odds ratio [OR], 2.4; P < .01), received instructions using the medication package as a visual aid (OR, 2.5; P = .02), and preferred AL over other antimalarials (OR, 2.7; P < .001). In contrast, children <5 years of age were significantly less likely to be adherent (OR, 0.5; P = .05)., Conclusions: Adherence to AL treatment for uncomplicated malaria was moderate, and children, who are the most likely to die of malaria, were less adherent than adults. Efforts to improve adherence should be focused on this vulnerable group. Interventions including the introduction of child-friendly antimalarial formulations, direct observation of the first dose, use of the AL package as a visual aid for instructions, and enhancing patient preference for AL could potentially increase AL adherence and overall effectiveness.

Background: In vivo efficacy assessments of the first-line treatments for Plasmodium falciparum malaria are essential for ensuring effective case management. In Ethiopia, artemether-lumefantrine (AL) has been the first-line treatment for uncomplicated P. falciparum malaria since 2004., Methods: Between October and November 2009, we conducted a 42-day, single arm, open label study of AL for P. falciparum in individuals >6 months of age at two sites in Oromia State, Ethiopia. Eligible patients who had documented P. falciparum mono-infection were enrolled and followed according to the standard 2009 World Health Organization in vivo drug efficacy monitoring protocol. The primary and secondary endpoints were PCR uncorrected and corrected cure rates, as measured by adequate clinical and parasitological response on days 28 and 42, respectively., Results: Of 4426 patients tested, 120 with confirmed falciparum malaria were enrolled and treated with AL. Follow-up was completed for 112 patients at day 28 and 104 patients at day 42. There was one late parasitological failure, which was classified as undetermined after genotyping. Uncorrected cure rates at both day 28 and 42 for the per protocol analysis were 99.1% (95% CI 95.1-100.0); corrected cure rates at both day 28 and 42 were 100.0%. Uncorrected cure rates at day 28 and 42 for the intention to treat analysis were 93.3% (95% CI 87.2-97.1) and 86.6% (95% CI 79.1-92.1), respectively, while the corrected cure rates at day 28 and 42 were 94.1% (95% CI 88.2-97.6) and 87.3% (95% CI 79.9-92.7), respectively. Using survival analysis, the unadjusted cure rate was 99.1% and 100.0% adjusted by genotyping for day 28 and 42, respectively. Eight P. falciparum patients (6.7%) presented with Plasmodium vivax infection during follow-up and were excluded from the per protocol analysis. Only one patient had persistent parasitaemia at day 3. No serious adverse events were reported, with cough and nausea/vomiting being the most common adverse events., Conclusions: AL remains a highly effective and well-tolerated treatment for uncomplicated falciparum malaria in the study setting after several years of universal access to AL. A high rate of parasitaemia with P. vivax possibly from relapse or new infection was observed., Trial Registration: NCT01052584.

Background: In 2005, the Ministry of Health in Ethiopia launched a major effort to distribute over 20 million long-lasting insecticidal nets, provide universal access to artemisinin-based combination therapy (ACTs), and train 30,000 village-based health extension workers., Methods and Findings: A cross-sectional, nationally representative Malaria Indicator Survey was conducted during the malaria transmission season in 2007. Multivariate logistic regression analyses were performed to assess the effect of women's malaria knowledge on household ITN ownership and women's ITN use. In addition, we investigated the effect of mothers' malaria knowledge on their children under 5 years of age's (U5) ITN use and their access to fever treatment on behalf of their child U5. Malaria knowledge was based on a composite index about the causes, symptoms, danger signs and prevention of malaria. Approximately 67% of women (n=5,949) and mothers of children U5 (n=3,447) reported some knowledge of malaria. Women's knowledge of malaria was significantly associated with household ITN ownership (adjusted Odds Ratio [aOR]=2.1; 95% confidence interval [CI] 1.6-2.7) and with increased ITN use for themselves (aOR=1.8; 95% CI 1.3-2.5). Knowledge of malaria amongst mothers of children U5 was associated with ITN use for their children U5 (aOR=1.6; 95% CI 1.1-2.4), but not significantly associated with their children U5 seeking care for a fever. School attendance was a significant factor in women's ITN use (aOR=2.0; 95% CI 1.1-3.9), their children U5's ITN use (aOR=4.4; 95% CI 1.6-12.1), and their children U5 having sought treatment for a fever (aOR=6.5; 95% CI 1.9-22.9)., Conclusions: Along with mass free distribution of ITNs and universal access to ACTs, delivery of targeted malaria educational information to women could improve ITN ownership and use. Efforts to control malaria could be influenced by progress towards broader goals of improving access to education, especially for women.

Background: The Centers for Disease Control and Prevention (CDC) is in the process of integrating the existing dual mechanisms for reporting cases of malaria diagnosed in the United States into a single electronic reporting mechanism. Before adoption of this new system, an evaluation of the existing systems for state-level reporting of malaria data to the CDC was conducted., Methods: CDC guidelines for evaluating surveillance systems were used to assess the attributes of the National Malaria Surveillance System (NMSS), the current National Notifiable Diseases Surveillance System (NNDSS), and the projected fully integrated NNDSS. We analyzed data collected from NMSS and NNDSS from 2001 to 2005 using the Chandra-Sekar-Deming method to estimate completeness of reporting., Results: The projected fully integrated system was assessed likely to perform better than either of the existing systems on all attributes except stability. The overall completeness of reporting was estimated to be 80.3 percent for NNDSS and 74.7 percent for NMSS., Conclusions: Both existing systems have reasonably high ascertainment of cases. A fully integrated system with malaria-specific data fields would improve upon existing systems if it proved to be stable.

Objective To assess the validity of health facility (HF)-based data on bednet and insecticide-treated bednet possession and use by children <5 years old. Methods We compared estimates based on data collected via HF surveys of under-5s attending well-child visits (e.g. immunizations) and sick-child visits vs. representative household surveys (a 'gold standard' method for measuring insecticide-treated net coverage). In Lindi region, Tanzania, we collected contemporaneous data on 637 under-5s via a HF survey (444 well-child visits and 193 sick-child visits), and on 305 households with an under-5 (including 354 children) via a household survey. In Rufiji district, Tanzania, we collected contemporaneous data on 1433 under-5s via a HF survey (911 well-child visits and 522 sick-child visits), and on 328 households with an under-5 (including 455 children) via a household survey. Results Possession of bednets by households with an under-5 was similar using HF data and household data in both Lindi region and Rufiji district. However, reported use of bednets was significantly higher in HF data than household data in both Lindi and Rufiji, as was reported use of insecticide-treated bednets. HF-based data accurately estimated community-level bednet possession in households with an under-5, but overestimated community-level bednet use by 9-35% and insecticide-treated bednet use by 15-21%. Conclusions Information bias rather than selection bias appears to be a key cause for the overestimation of bednet and insecticide-treated bednet use (e.g. social desirability bias: caretakers of under-5s attending health facilities might be more likely to report using bednets and insecticide-treated bednets). Additional studies of the validity, cost and utility of HF-based data to monitor insecticide-treated bednet use are needed before recommending this monitoring strategy for widespread use. Overestimating insecticide-treated bednet use could lead to inappropriate public health actions and missed opportunities for achieving local and global public health goals.

Malaria is a leading cause of morbidity and mortality worldwide. Prompt diagnosis and treatment are critical factors in reducing morbidity and mortality, as delayed treatment of malaria increases the risk of death. Microscopy has long been the standard of malaria diagnosis, but newer diagnostic tests now offer advantages in certain settings. Malaria diagnosis is complicated by the fact that acquired immunity to malaria can result in asymptomatic infections. In a symptomatic (febrile) patient, no existing malaria diagnostic test can distinguish malarial illness from parasitemia with concomitant fever of another cause. In this review we discuss the available malaria diagnostic tests, appropriate applications for each, and the challenges of malaria diagnosis in both endemic and non-endemic settings.

Background: The Roll Back Malaria strategy recommends a combination of interventions for malaria control. Zanzibar implemented artemisinin-based combination therapy (ACT) for uncomplicated malaria in late 2003 and long-lasting insecticidal nets (LLINs) from early 2006. ACT is provided free of charge to all malaria patients, while LLINs are distributed free to children under age 5 y ("under five") and pregnant women. We investigated temporal trends in Plasmodium falciparum prevalence and malaria-related health parameters following the implementation of these two malaria control interventions in Zanzibar., Methods and Findings: Cross-sectional clinical and parasitological surveys in children under the age of 14 y were conducted in North A District in May 2003, 2005, and 2006. Survey data were analyzed in a logistic regression model and adjusted for complex sampling design and potential confounders. Records from all 13 public health facilities in North A District were analyzed for malaria-related outpatient visits and admissions. Mortality and demographic data were obtained from District Commissioner's Office. P. falciparum prevalence decreased in children under five between 2003 and 2006; using 2003 as the reference year, odds ratios (ORs) and 95% confidence intervals (CIs) were, for 2005, 0.55 (0.28-1.08), and for 2006, 0.03 (0.00-0.27); p for trend < 0.001. Between 2002 and 2005 crude under-five, infant (under age 1 y), and child (aged 1-4 y) mortality decreased by 52%, 33%, and 71%, respectively. Similarly, malaria-related admissions, blood transfusions, and malaria-attributed mortality decreased significantly by 77%, 67% and 75%, respectively, between 2002 and 2005 in children under five. Climatic conditions favorable for malaria transmission persisted throughout the observational period., Conclusions: Following deployment of ACT in Zanzibar 2003, malaria-associated morbidity and mortality decreased dramatically within two years. Additional distribution of LLINs in early 2006 resulted in a 10-fold reduction of malaria parasite prevalence. The results indicate that the Millennium Development Goals of reducing mortality in children under five and alleviating the burden of malaria are achievable in tropical Africa with high coverage of combined malaria control interventions.

Regulatory infringements are extremely common in low-income countries, especially with respect to retail pharmaceutical sales. There have been few practical suggestions on public policy responses other than stricter regulatory enforcement, which governments are often unable, or unwilling, to do. This paper explores the challenges of regulating retail drug sellers, and potential solutions, through a case study of malaria treatment in rural Tanzania where small drug shops are a common source of medicine. Infringement of health-related regulation was extremely common. Most stores lacked valid permits, and illegal stocking of prescription-only medicines and unpackaged tablets was the norm. Most stocked unregistered drugs, and no serving staff met the qualification requirements. Infringements are likely to have reflected infrequent regulatory inspections, a failure of regulatory authorities to implement sanctions, successful concealment of regulatory violations, and the tacit permission of local regulatory staff. Eliminating regulatory infringements is unlikely to be feasible, and could be undesirable if access to essential medicines is reduced. Alternatives include bringing official drug regulation closer into line with locally legitimate practices; greater use of positive incentives for providers; and consumer involvement. Such a change in approach has the potential to provide a firmer platform for public-private collaboration to improve shop-based treatment.

Objective: To determine the economic burden of malaria in a rural Tanzanian setting and identify any differences by socioeconomic status and season., Methods: Interviews of 557 households in south eastern Tanzania between May and December 2004, on consumption and malaria-related costs., Results: Malaria-related expenses were significantly higher in the dry, non-malarious season than in the rainy season. Households sought treatment more frequently and from more expensive service providers in the dry season, when they have more money. Malaria expenses did not vary significantly across socioeconomic status quintiles, but poorer households spent a higher proportion of their consumption in both seasons., Conclusion: Poorer households bear a greater economic burden from malaria relative to their consumption than better-off households. Households are particularly vulnerable to malaria in the rainy season, when malaria prevalence is highest but liquidity is lower. Alternative strategies to assist households to cope with seasonal liquidity issues, including insurance, should be investigated.

We have measured microsatellite diversity at 26 markers around the dhfr gene in pyrimethamine-sensitive and -resistant parasites collected in southeast Africa. Through direct comparison with diversity on sensitive chromosomes we have found significant loss of diversity across a region of 70 kb around the most highly resistant allele which is evidence of a selective sweep attributable to selection through widespread use of pyrimethamine (in combination with sulfadoxine) as treatment for malaria. Retrospective analysis through four years of direct and continuous selection from use of sulfadoxine-pyrimethamine as first-line malaria treatment on a Plasmodium falciparum population in KwaZulu Natal, South Africa, has revealed how recombination significantly narrowed the margins of the selective sweep over time. A deterministic model incorporating selection coefficients measured during the same interval indicates that the transition was toward a state of recombination-selection equilibrium. We compared loss of diversity around the same resistance allele in two populations at either extreme of the range of entomological inoculation rates (EIRs), namely, under one infective bite per year in Mpumalanga, South Africa, and more than one per day in southern Tanzania. EIRs determine effective recombination rates and are expected to profoundly influence the dimensions of the selective sweep. Surprisingly, the dimensions were broadly consistent across both populations. We conclude that despite different recombination rates and contrasting drug selection histories in neighboring countries, the region-wide movement of resistant parasites has played a key role in the establishment of resistance in these populations and the dimensions of the selective sweep are dominated by the influence of high initial starting frequencies.