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To maximise the likelihood of success, global health programmes need repeated, honest appraisal of their own weaknesses, with research undertaken to address any identified gaps. There is still much to be learned to optimise work against neglected tropical diseases. To facilitate that learning, a comprehensive research and development plan is required. Here, we discuss how such a plan might be developed.

Microscopy performed on stained films of peripheral blood for detection, identification and quantification of malaria parasites is an essential reference standard for clinical trials of drugs, vaccines and diagnostic tests for malaria. The value of data from such research is greatly enhanced if this reference standard is consistent across time and geography. Adherence to common standards and practices is a prerequisite to achieve this. The rationale for proposed research standards and procedures for the preparation, staining and microscopic examination of blood films for malaria parasites is presented here with the aim of improving the consistency and reliability of malaria microscopy performed in such studies. These standards constitute the core of a quality management system for clinical research studies employing microscopy as a reference standard. They can be used as the basis for the design of training and proficiency testing programmes as well as for procedures and quality assurance of malaria microscopy in clinical research.

The Global Technical Strategy for Malaria 2016–2030 was adopted by the 68th World Health Assembly in May 2015. It emphasizes the importance of scaling up malaria control responses and moving towards elimination [1]. It is anticipated that such scale-up will help countries reduce and, eventually, eliminate the human suffering caused by malaria as well as contribute more broadly to the achievement of the Sustainable Development Goals. The Global Technical Strategy consists of three main pillars, underpinned by two supporting elements (Fig. 1). The first of the supporting elements, harnessing innovation and expanding research, is also recognized as critical in the global control and elimination of other diseases, such as tuberculosis [2]. It is recognized that operational and implementation research are needed to ensure that existing interventions are applied effectively and efficiently in different contexts and, as new interventions become available, to ensure that innovation is deployed appropriately and to maximum effect. Fig. 1 The World Health Organization Global Technical Strategy for Malaria 2016–2030 In 2011, the malERA Consultative Group on Health Systems and Operational Research published a Research Agenda for Malaria Eradication: Health Systems and Operational Research [3]. The WHO Global Malaria Programme (GMP) has more recently published the report of a multi-partner meeting that discussed operational challenges for malaria elimination, identified priority operational research questions and recommended ways forward [4]. Other organizations have produced similar lists of operational research priorities [5]. There is no shortage of recommendations on the priorities for operational research and most authors consider operational research to be relatively straightforward and, if using routinely-collected data, inexpensive. However, a recent review of the literature on malaria control and elimination between 2008 and 2013 (15,886 articles) revealed that less than 4 % met the definition of operational research. Of these articles only 19 (3.8 %) were related to malaria surveillance [6]. It would seem that operational research, though recognized as critically important to the success of global strategies for malaria control and elimination, is not so commonly undertaken or at least not so commonly published. Indeed, it could be argued that the difference between these two is academic since unpublished research is unlikely to inform widespread scaling up of malaria activities. Why is so little operational research done when much of it would be straightforward and inexpensive and could be done within the context of routine malaria programme activities? It is a long-standing problem. In 2007, a report of the Global Fund’s Technical Review Panel noted that operational research was often absent or inadequately elaborated in proposals [7]. The report further stated that proposals clearly described bottlenecks to progress and that these provide the basis for operational research questions that seem obvious but were not proposed. How can operational research be promoted to support the new Global Technical Strategy for Malaria? A good start would be to look at the recent experiences of other disease control programmes. In 2011, the WHO listed its priorities in operational research to improve tuberculosis care and control. One of the five priority areas for operational research was capacity-building for operational research. Key questions included: what are the existing models of operational health research capacity? What is the impact of existing training models in terms of products, outputs and outcomes? How to ensure sustainable operational research capacity at the national level? 4 years later, its Global Action Framework for TB Research described some of the lessons from this exercise and has provided case studies of how operational research capacity has been built in public health programmes in low-income and middle-income countries [2]. One of these case studies was the Structured Operational Research and Training Initiative (SORT IT) a global partnership-based initiative led by the Special Programme for Research and Training in Tropical Diseases (TDR) based at WHO [8]. Started in 2012, SORT IT aims to support countries to: conduct operational research around their own priorities, build adequate and sustainable operational research capacity within public health programmes; and make evidence-informed improvements to programme implementation. More than 400 health workers in 80 countries have been trained through SORT IT to date. Over the course of 1 year, participating health workers learn the skills required to develop operational research questions, protocols, data capture and analysis instruments and to publish their work. Over 90 % of participants publish their research in the peer reviewed literature and many go on to become facilitators in further SORT IT training courses. The training is currently being delivered in English, Russian and Spanish, with the transition into French underway. The model has been recognized as a reliable way to build the much-needed research capacity in public health programmes in LMICs [9, 10]. Having its roots in a training course run by Medecins Sans Frontieres and the International Union Against Tuberculosis and Lung Diseases, that supported tuberculosis control, SORT IT is now delivering regional and national capacity-building for operational research in all WHO regions and in number of disease areas [11, 12]. In TDR-supported SORT IT Programmes, the core training course is embedded within broader capacity-building activities in knowledge management (research needs assessments and prioritization, dissemination of research findings and evidence-informed policy making). Efforts are also made to consolidate research capacity that has been built through SORT IT by providing participants with further research training and small research grants. In 2014, two research studies related to malaria elimination were supported by SORT IT [13, 14]. In 2015–16, in collaboration with the Global Malaria Programme and the WHO African Regional Office (AFRO), a SORT IT programme supported four malaria-eliminating countries in Southern Africa: Botswana, Namibia, South Africa and Swaziland. A Supplement of Malaria Journal is in preparation to feature research outputs of this SORT IT programme. It is hoped that this Supplement will encourage others to adopt approaches like SORT IT, conduct operational research while building research capacity in malaria programmes and make evidence-informed improvements to policy and practice. On the occasion of the 2016 World Malaria Day the authors would like to highlight both the need for, and the feasibility of, building operational research capacity in malaria programmes in low- and middle-income countries if the ambitions of the Global Technical Strategy for Malaria 2016–2030 are to be achieved.

Background The climate variables that directly influence vector-borne diseases’ ecosystems are mainly temperature and rainfall. This is not only because the vectors bionomics are strongly dependent upon these variables, but also because most of the elements of the systems are impacted, such as the host behavior and development and the pathogen amplification. The impact of the climate changes on the transmission patterns of these diseases is not easily understood, since many confounding factors are acting together. Consequently, knowledge of these impacts is often based on hypothesis derived from mathematical models. Nevertheless, some direct evidences can be found for several vector-borne diseases. Main body Evidences of the impact of climate change are available for malaria, arbovirus diseases such as dengue, and many other parasitic and viral diseases such as Rift Valley Fever, Japanese encephalitis, human African trypanosomiasis and leishmaniasis. The effect of temperature and rainfall change as well as extreme events, were found to be the main cause for outbreaks and are alarming the global community. Among the main driving factors, climate strongly influences the geographical distribution of insect vectors, which is rapidly changing due to climate change. Further, in both models and direct evidences, climate change is seen to be affecting vector-borne diseases more strikingly in fringe of different climatic areas often in the border of transmission zones, which were once free of these diseases with human populations less immune and more receptive. The impact of climate change is also more devastating because of the unpreparedness of Public Health systems to provide adequate response to the events, even when climatic warning is available. Although evidences are strong at the regional and local levels, the studies on impact of climate change on vector-borne diseases and health are producing contradictory results at the global level. Conclusions In this paper we discuss the current state of the results and draw on evidences from malaria, dengue and other vector-borne diseases to illustrate the state of current thinking and outline the need for further research to inform our predictions and response. Electronic supplementary material The online version of this article (10.1186/s40249-019-0565-1) contains supplementary material, which is available to authorized users.

Despite having the highest Plasmodium vivax burden in the world, molecular epidemiological data from Papua New Guinea (PNG) for this parasite remain limited. To investigate the molecular epidemiology of P. vivax in PNG, 574 isolates collected from four catchment sites in East Sepik (N = 1) and Madang (N = 3) Provinces were genotyped using the markers MS16 and msp1F3. Genetic diversity and prevalence of P. vivax was determined for all sites. Despite a P. vivax infection prevalence in the East Sepik (15%) catchments less than one-half the prevalence of the Madang catchments (27-35%), genetic diversity was similarly high in all populations (He = 0.77-0.98). High genetic diversity, despite a marked difference in infection prevalence, suggests a large reservoir of diversity in P. vivax populations of PNG. Significant reductions in transmission intensity may, therefore, be required to reduce the diversity of parasite populations in highly endemic countries such as PNG.

This paper summarizes our current understanding of the biology of Plasmodium vivax, how it differs from Plasmodium falciparum, and how these differences explain the need for P. vivax-tailored interventions. The article further pinpoints knowledge gaps where investments in research are needed to help identify and develop such specific interventions. The principal obstacles to reduce and eventually eliminate P. vivax reside in 1) its higher vectorial capacity compared with P. falciparum due to its ability to develop at lower temperature and over a shorter sporogonic cycle in the vector, allowing transmission in temperate zones and making it less sensitive to vector control measures that are otherwise effective on P. falciparum; 2) the presence of dormant liver forms (hypnozoites), sustaining multiple relapsing episodes from a single infectious bite that cannot be diagnosed and are not susceptible to any available antimalarial except primaquine, with routine deployment restricted by toxicity; 3) low parasite densities, which are difficult to detect with current diagnostics leading to missed diagnoses and delayed treatments (and protracted transmission), coupled with 4) transmission stages (gametocytes) occurring early in acute infections, before infection is diagnosed.

Aim To determine the age specific immunity profile for rubella from three discrete study populations in Papua New Guinea, and to inform policy regarding the possible introduction of rubella vaccine. Background In 2005, the Western Pacific Region (WPR), of which Papua New Guinea (PNG) is a member state, declared the goal of regional measles elimination by 2012. Recently, WPR has incorporated an accelerated control goal for rubella and congenital rubella syndrome (CRS). PNG currently recommends two doses of measles vaccination at 6 and 9 months of age with a monovalent measles vaccine, which does not include rubella vaccine. Methods Convenience samples were collected from 1326 eligible participants in PNG and assessed for rubella immunity using the Dade Behring Enzygnost™ Anti-Rubella-Virus enzyme immunoassay. Nearly 34% were collected during an age stratified prospective survey of febrile patients in Madang Province; approximately 49% were collected from women of childbearing age in East Sepik and Milne Bay Provinces. Remaining specimens were collected from 6 to 7-month-old infants in Port Moresby prior to receiving the first dose of measles vaccine. Findings Of all samples tested, 65.2% (95% confidence interval (CI): 62.6–67.8) had evidence of immunity to rubella infection. Of women more than 15 years of age, 91.6% (95% CI: 89.4–93.5) were immune. The force of infection was highest between 5 and 19 years of age. Conclusions Although a population-based sample was not used, our multi-centre study of the population immunity profile suggests that immunity against rubella is extremely high in most women of childbearing age, but women who become pregnant at an early age may be at high risk of rubella infection during pregnancy and potential delivery of an infant with CRS. Routine measles vaccine coverage, a proxy for measles-rubella vaccine coverage, as measured in recently published studies, is well below the WHO target of 80% coverage. Introduction of a child or infant dose of rubella vaccine requires caution and further study.

Despite consistent evidence of a protective effect of alpha(+)-thalassemia against severe Plasmodium falciparum disease, the mechanisms underlying this protection remain unknown. An increase in risk of Plasmodium vivax malaria in early childhood resulting in a cross-species protection against severe P. falciparum malaria has been proposed as a possible mechanism in Melanesian children. The association of alpha(+)-thalassemia genotypes with a risk of P. falciparum and P. vivax infection and uncomplicated illness was reassessed in a cohort of 1,112 Papua New Guinean children, followed from 3-21 months of age. Three hundred and eighty-nine (35.0%) children were homozygous for a(+)-thalassemia (-a/-a), 506 (45.5%) heterozygous (aa/-a) and 217 (19.5%) homozygous for the wild-type allele. No significant differences in the incidence of P. falciparum (Pf) or P. vivax (Pv) malaria were observed between alpha(+)-thalassemia homozygote (Pf: Incidence rate ratio (IRR) = 1.13, CI(95) (0.82,1.56), P = 0.45, Pv: IRR = 1.15, CI(95) (0.9881.56), P = 0.31), heterozygote (Pf: IRR = 0.98, CI(95) (0.71,1.34), P = 0.93, Pv: IRR = 1.14, CI(95) (0.88,1.48), P =0.33) and wild-type children. The prevalence of infection with either species did not differ between alpha(+)-thalassemia genotypes, although densities of P. vivax (but not of P. falciparum) infections were significantly higher in alpha(+)-thalassemia homozygote and heterozygote children. An excessive risk of moderate-to-severe anemia (hemoglobin (Hb) > 8 g/dl) was observed in alpha(+)-thalassemia homozygote children (IRR = 1.54, CI(95)(1.12, 2.11), P = 0.008). This study therefore failed to confirm an increased risk of P. vivax or P. falciparum malaria in very young, alpha(+)-thalassemic children without significant levels of acquired immunity. This confirms the lack of protection by alpha(+)-thalassemia against uncomplicated P. falciparum and challenges the hypothesis of immunological cross-protection between P. falciparum and P. vivax as a mechanism underlying alpha(+)-thalassemia protection against severe P. falciparum disease in Melanesian children

Objectives To conduct an in-depth investigation of the epidemiology of malaria in the Papua New Guinea (PNG) highlands and provide a basis for evidence-based planning and monitoring of intensified malaria control activities. Methods Between December 2000 and July 2005, 153 household-based, rapid malaria population surveys were conducted in 112 villages throughout the central PNG highlands. The presence of malaria infections was determined by light microscopy and risk factors assessed using a structured questionnaire. The combined dataset from all individually published surveys was reanalysed. Results The prevalence of malaria infections in the different surveys ranged from 0.0% to 41.8% (median 4.3%) in non-epidemic surveys and 6.6% to 63.2% (median 21.2%, P 1600 m. Outside epidemics, prevalence decreased significantly with altitude, was reduced in people using bed nets [odds ratio (OR) = 0.8, P

Background. In malaria-endemic areas it is recommended that febrile children be tested for malaria by rapid diagnostic test (RDT) or blood slide (BS) and receive effective malaria treatment only if results are positive. However, RDTs are known to perform less well for Plasmodium vivax. We evaluated the safety of withholding antimalarial drugs from young Papua New Guinean children with negative RDT results in areas with high levels of both Plasmodium falciparum and P. vivax infections. Methods. longitudinal prospective study of children aged 3-27 months visiting outpatient clinics for fever. RDT was administered at first visit. RDT and microscopy were performed if children returned because of persistent symptoms. Outcomes were rates of reattendance and occurrence of severe illnesses. Results. Of 5670 febrile episodes, 3942 (70%) involved a negative RDT result. In 133 cases (3.4%), the children reattended the clinic within 7 days for fever, of whom 29 (0.7%) were parasitemic by RDT or microscopy. Of children who reattended, 24 (0.7%) presented with a severe illness: 2 had lower respiratory tract infections (LRTIs) with low-density P. vivax on BS; 2 received a diagnosis of P. vivax malaria on the basis of RDT but BSs were negative; 16 had LRTIs; 3 had alternative diagnoses. Of these 24, 22 were cured at day 28. Two children died of illnesses other than malaria and were RDT and BS negative at the initial and subsequent visits. Conclusion. Treatment for malaria based on RDT results is safe and feasible even in infants living in areas with moderate to high endemicity for both P. falciparum and P. vivax infections.

The Duffy antigen receptor for chemokines (DARC or Fy glycoprotein) carries antigens that are important in blood transfusion and is the main receptor used by Plasmodium vivax to invade reticulocytes. Southeast Asian ovalocytosis (SAO) results from an alteration in RBC membrane protein band 3 and is thought to mitigate susceptibility to falciparum malaria. Expression of some RBC antigens is suppressed by SAO, and we hypothesized that SAO may also reduce Fy expression, potentially leading to reduced susceptibility to vivax malaria. Blood samples were collected from individuals living in the Madang Province of Papua New Guinea. Samples were assayed using a flow cytometry assay for expression of Fy on the surface of RBC and reticulocytes by measuring the attachment of a phycoerythrin-labeled Fy6 antibody. Reticulocytes were detected using thiazole orange. The presence of the SAO mutation was confirmed by PCR. There was a small (approximately 10%) but statistically significant (p=0.049, Mann-Whitney U test) increase in Fy expression on SAO RBC compared with RBC from individuals without this polymorphism: mean Fy expression (mean fluorescence intensity [MFI]) was 10.12 ± 1.22 for SAO heterozygotes versus an MFI of 8.95 ± 1.1 for individuals without SAO. For reticulocytes the MFI values were 27.61 ± 19.12 for SAO heterozygotes and 16.47 ± 3.81 for controls. SAO is associated with increased and not decreased Fy6 expression so that susceptibility to P. vivax infection is unlikely to be affected. Immunohematology 2009;25:63–66.

During pregnancy, specific variants of Plasmodium falciparum-infected erythrocytes (IEs) can accumulate in the placenta through adhesion to chondroitin sulfate A (CSA) mediated by expression of PfEMP1 encoded by var2csa-type genes. Antibodies against these variants are associated with protection from maternal malaria. We evaluated antibodies among Kenyan, Papua New Guinean, and Malawian men and Kenyan children against two different CSA-binding P. falciparum isolates expressing var2csa variants. Specific IgG was present at significant levels among some men and children from each population, suggesting exposure to these variants is not exclusive to pregnancy. However, the level and prevalence of antibodies was substantially lower overall than exposed multigravidas. IgG-binding was specific and did not represent antibodies to subpopulations of non-CSA-binding IEs, and some sera inhibited IE adhesion to CSA. These findings have significant implications for understanding malaria pathogenesis and immunity and may be significant for understanding the acquisition of immunity to maternal malaria.

Although Plasmodium malariae was first described as an infectious disease of humans by Golgi in 1886 and Plasmodium ovale identified by Stevens in 1922, there are still large gaps in our knowledge of the importance of these infections as causes of malaria in different parts of the world. They have traditionally been thought of as mild illnesses that are caused by rare and, in case of P. ovale, short-lived parasites. However, recent advances in sensitive PCR diagnosis are causing a re-evaluation of this assumption. Low-level infection seems to be common across malaria-endemic areas, often as complex mixed infections. The potential interactions of P. malariae and P. ovale with Plasmodium falciparum and Plasmodium vivax might explain some basic questions of malaria epidemiology, and understanding these interactions could have an important influence on the deployment of interventions such as malaria vaccines.

Using in vivo samples from treatment failure malaria cases, we demonstrate the high sensitivity of the parasite lactase dehydrogenase (pLDH)-based OptiMAL rapid diagnostic test in the detection of P. falciparum gametocytes. This high sensitivity limits the use of pLDH-based tests in the monitoring of treatment outcomes in circumstances where gametocytemia is common.

Levels of C-reactive protein (CRP), a classic marker for the acute phase response (APR), were measured in children with asymptomatic malaria infection in the Amele region of Papua New Guinea (PNG). Despite the presence of parasitemia, the prevalence of CRP levels consistent with an APR (CRP > 10 μg/mL) was very low (< 10%). Splenomegaly was significantly associated with increased parasitemia (P < 0.001) and CRP levels (P < 0.001), highlighting the importance of splenomegaly as an indicator of recent high density infection in this population. Multivariate analysis showed that CRP levels were significantly associated with splenomegaly, fever, hemoglobin, and age (P ≤ 0.002). CRP levels also increased with increasing parasitemia (P < 0.001) but remained < 3.5 μg/mL. The low levels of CRP indicate that children in the Amele modulate inflammation associated with malaria.

The Asia Pacific Malaria Elimination Network (APMEN) is a collaboration of 18 country partners committed to eliminating malaria from within their borders. Over the past 5 years, APMEN has helped to build the knowledge, tools and in-country technical expertise required to attain this goal. At its inaugural meeting in Brisbane in 2009, Plasmodium vivax infections were identified across the region as a common threat to this ambitious programme; the APMEN Vivax Working Group was established to tackle specifically this issue. The Working Group developed a four-stage strategy to identify knowledge gaps, build regional consensus on shared priorities, generate evidence and change practice to optimize malaria elimination activities. This case study describes the issues faced and the solutions found in developing this robust strategic partnership between national programmes and research partners within the Working Group. The success of the approach adopted by the group may facilitate similar applications in other regions seeking to deploy evidence-based policy and practice. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0958-y) contains supplementary material, which is available to authorized users.

BACKGROUND: Drug resistance remains a major obstacle to malaria treatment and control. It can arise and spread rapidly, and vary substantially even at sub-national level. National malaria programmes require cost-effective and timely ways of characterizing drug-resistance at multiple sites within their countries. METHODS: An improved multiplexed post-PCR ligase detection reaction-fluorescent microsphere assay (LDR-FMA) was used to simultaneously determine the presence of mutations in chloroquine resistance transporter (crt), multidrug resistance 1 (mdr1), dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) genes in Plasmodium falciparum (n = 727) and Plasmodium vivax (n = 574) isolates collected in 2006 from cross-sectional community population surveys in two geographically distinct regions (Madang and East Sepik) of Papua New Guinea (PNG) where strong regional differences in in vivo aminoquinoline and antifolate therapeutic efficacy had previously been observed. Data were compared to those of a follow-up survey conducted in 2010. RESULTS: Despite some very low parasite densities, the assay successfully amplified all P. falciparum and P. vivax loci in 77 and 69 % of samples, respectively. In 2006, prevalences of pfdhfr (59R-108 N) double mutation/wild type pfdhps haplotype, pfcrt SVMNT haplotype (72S-76T double mutation), and 86Y pfmdr1 mutation all exceeded 90 %. For P. vivax, 65 % carried at least two pvdhfr mutations, 97 % the 647P pvdhps mutation and 54 % the 976F pvmdr1 mutation. Prevalence of mutant haplotypes was higher in Madang than East Sepik for pfcrt SVMNT (97.4 vs 83.3 %, p = 0.001), pfdhfr (59R-108 N) (100 vs 90.6 %, p = 0.001), pvdhfr haplotypes (75.8 vs 47.6 %, p = 0.001) and pvmdr1 976F (71.2 vs 26.2 %, p < 0.001). Data from a subsequent Madang survey in 2010 showed that the prevalence of pfdhps mutations increased significantly from 30 % (p < 0.001) as did the prevalence of pvdhfr mutant haplotypes (from 75.8 to 97.4 %, p = 0.012). CONCLUSIONS: This LDR-FMA multiplex platform shows feasibility for low-cost, high-throughput, rapid characterization of a broad range of drug-resistance markers in low parasitaemia infections. Significant geographical differences in mutation prevalence correlate with previous genotyping surveys and in vivo trials and may reflect variable drug pressure and differences in health-care access in these two PNG populations.

Background Bacterial meningitis remains an important infection globally, with the greatest burden in children in low-income settings, including Papua New Guinea (PNG). We present serotype, antimicrobial susceptibility and outcome data from paediatric meningitis patients prior to introduction of Haemophilus influenzae type b (Hib) and pneumococcal conjugate vaccines (PCVs) in PNG, providing a baseline for evaluation of immunisation programs. Methods Cerebrospinal fluid (CSF) was collected from children admitted to Goroka General Hospital with suspected meningitis between 1996 and 2005. Culture and sensitivity was conducted, and pneumococci and H. influenzae were serotyped. Laboratory findings were linked to clinical outcomes. Results We enrolled 1884 children. A recognised pathogen was identified in 375 children (19.9 %). Streptococcus pneumoniae (n = 180) and Hib (n = 153) accounted for 88.8 % of pathogens isolated. 24 different pneumococcal serogroups were identified; non-PCV types 2, 24 and 46 accounted for 31.6 % of pneumococcal meningitis. 10- and 13-valent PCVs would cover 44.1 % and 45.4 % of pneumococcal meningitis respectively. Pneumococcal isolates were commonly resistant to penicillin (21.5 %) and 23 % of Hib isolates were simultaneously resistant to ampicillin, co-trimoxazole and chloramphenicol. The case fatality rate in patients with a recognised bacterial pathogen was 13.4 % compared to 8.5 % in culture-negative patients. Conclusions If implemented in routine expanded programme of immunisation (EPI) with high coverage, current PCVs could prevent almost half of pneumococcal meningitis cases. Given the diversity of circulating serotypes in PNG serotype replacement is of concern. Ongoing surveillance is imperative to monitor the impact of vaccines. In the longer term vaccines providing broader protection against pneumococcal meningitis will be needed. Electronic supplementary material The online version of this article (doi:10.1186/s12879-015-1197-0) contains supplementary material, which is available to authorized users.

The Malaria Policy Advisory Committee to the World Health Organization held its sixth meeting in Geneva, Switzerland from 10 to 12 September 2014. This article provides a summary of the discussions, conclusions and recommendations from that meeting. Meeting sessions covered the following: an update on drug resistance and containment including an assessment on the feasibility of elimination of Plasmodium falciparum malaria in the Greater Mekong Subregion; guidance on the control of residual malaria transmission by behaviourally resistant vectors; progress on the implementation of the Global Plan for Insecticide Resistance Management; updates on the Global Technical Strategy, Global Malaria Action Plan and the Plasmodium vivax technical brief; gaps in current World Health Organization Global Malaria Programme guidance for acceleration to elimination; surveillance, monitoring and evaluation; the updated World Health Organization Guidelines for the Prevention and Treatment of Malaria; Round 5 product testing for rapid diagnostic tests; and Intermittent Preventive Treatment for infants. Policy statements, position statements, and guidelines that arise from the Malaria Policy Advisory Committee meeting conclusions and recommendations will be formally issued and disseminated to World Health Organization Member States by the World Health Organization Global Malaria Programme.

During a prospective study of red cell variants and severe malaria in children, a surprising observation was the occurrence of dark urine. Children were grouped according to urine findings: 22 had dark urine that contained a haem protein (Group I), 93 had urine of normal colour that contained a haem protein (Group II) and 236 had normal urine (Group III). To investigate the cause of dark urine, haemolysis and muscle cell injury were assessed. Intravascular haemolysis was greater in Group I than in Groups II and III. However, anaemia was more severe in Group III and is likely to have resulted mainly from extravascular haemolysis. Median plasma myoglobin concentrations were greater in Groups I and II than Group III (P = 0.00060). Plasma myoglobin was greater in children with cerebral malaria, hyperlactataemia and those who died but was not associated with acidosis. Urine myoglobin was greater in Group I than Groups II and III (P = 0.00054). It is likely that both haemoglobin and myoglobin contributed to dark urine. The association between muscle cell injury and coma suggests sequestration of parasitized red cells as a common underlying pathology. In malaria, hyperlactataemia may result directly from breakdown of muscle protein as well as tissue hypoxia.

Drug treatment of severe malaria must be rapidly effective. Suppositories may be valuable for childhood malaria when circumstances prevent oral or parenteral therapy. We compared artesunate suppositories ( n = 41; 8 to 16 mg/kg of body weight at 0 and 12 h and then daily) with intramuscular (i.m.) artemether ( n = 38; 3.2 mg/kg at 0 h and then 1.6 mg/kg daily) in an open-label, randomized trial with children with severe Plasmodium falciparum malaria in Papua New Guinea (PNG). Parasite density and temperature were measured every 6 h for ≥72 h. Primary endpoints included times to 50% and 90% parasite clearance (PCT 50 and PCT 90 ) and the time to per os status. In a subset of 29 patients, plasma levels of artemether, artesunate, and their common active metabolite dihydroartemisinin were measured during the first 12 h. One suppository-treated patient with multiple complications died within 2 h of admission, but the remaining 78 recovered uneventfully. Compared to the artemether-treated children, those receiving artesunate suppositories had a significantly earlier mean PCT 50 (9.1 versus 13.8 h; P = 0.008) and PCT 90 (15.6 versus 20.4 h; P = 0.011). Mean time to per os status was similar for each group. Plasma concentrations of primary drug plus active metabolite were significantly higher in the artesunate suppository group at 2 h postdose. The earlier initial fall in parasitemia with artesunate is clinically advantageous and mirrors higher initial plasma concentrations of active drug/metabolite. In severely ill children with malaria in PNG, artesunate suppositories were at least as effective as i.m. artemether and may, therefore, be useful in settings where parenteral therapy cannot be given.

Background Subacute sclerosing panencephalitis (SSPE) is a rare progressive inflammatory disease characterized by the persistent infection of the brain by the measles virus. However, the immunological pathophysiology of SSPE is still unclear. Methods We measured the concentrations of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-2 (IL-2), IL-4, IL-6, IL-10, and soluble TNF receptor 1 (sTNFR1) in the serum and cerebrospinal fluid (CSF) of 23 patients with SSPE in Papua New Guinea (PNG), a country with a high incidence of SSPE, and Japanese controls by cytometric bead array or ELISA. Results The serum IL-6 and IL-10 levels of SSPE patients were significantly higher than those of controls ( p = 0.0075, and p = 0.0019, respectively). The serum IL-6 and IL-10 levels of SSPE patients with fever were significantly higher than those without fever ( p = 0.0107, and p = 0.0006, respectively). The CSF IL-6 levels of SSPE patients were significantly higher than those of controls ( p = 0.0218). The CSF IL-6 levels of SSPE patients with myoclonic jerks were significantly higher than those without myoclonic jerks ( p = 0.0189). There were no differences in serum IFN-γ, TNF-α, IL-2, IL-4, and sTNFR1, or CSF IFN-γ, TNF-α, IL-2, IL-4, IL-10, and sTNFR1 levels between the affected patients and controls. Conclusion Our present study suggests that serum IL-6 and IL-10 levels are related to fever, and the CSF IL-6 level, myoclonic jerks, in SSPE patients in PNG.

More than 200 female sex workers (FSWs) participating in commercial sex along the Highlands Highway of Papua New Guinea were identified in a previous survey. This has implications for the spread of sexually transmitted infections (STIs) and human immunodeficiency virus (HIV) to areas and population groups serviced by the road.The goal of this study was to estimate the prevalence of gonorrhea, chlamydia, syphilis, trichomoniasis, and HIV among FSWs in Goroka and Kainantu in the Eastern Highlands Province (EHP) and to identify correlates that could be considered in intervention and control.Self-identified FSWs recruited through the Goroka Sex Workers Peer-Mediated Programme were invited to participate. All consenting FSWs underwent pretest counseling and provided sociodemographic and behavioral data using a structured questionnaire. The women were also asked to self-collect vaginal specimens and to provide peripheral blood to detect the respective STIs and HIV.Results were available for 211 FSWs. None of the women were positive for HIV. The overall estimated rates for gonorrhea, chlamydia, syphilis, and trichomoniasis were 21%, 19%, 24%, and 51%, respectively. Seventy-four percent were positive for at least 1 STI and 43% had multiple STI infections. High-risk sexual behaviors were found to be common among the women, including low and inconsistent use of condoms, with most of them attributing this to unavailability, dislike by or familiarity with clients, and being drunk and/or high on marijuana.STIs are prevalent among FSWs in Goroka and Kainantu in the EHP and are maintained by widespread high-risk sexual behaviors, including low use of condoms. Implications for their spread through the highway warrants increased efforts in intervention. Apart from a need to promote condom acceptance, distribution, and use, other high-risk sexual behavior and correlates identified in this study provide important considerations for intervention and control in this population.

Melioidosis is a potentially fatal disease caused by the bacterium Burkholderia pseudomallei. Individuals with subclinical melioidosis have no apparent clinical signs or symptoms, and are identified only by positive serology. The present study is the first to investigate cell-mediated immune (CMI) responses following in vitro stimulation with B. pseudomallei antigens in peripheral blood mononuclear cells (PBMC), collected under field conditions in Papua New Guinea (PNG) from individuals with exposure to B. pseudomallei (n = 13). While five had a clinical history of melioidosis (C(+)), the remaining individuals (n = 8) were seropositive, yet healthy with no clinical history of melioidosis (S(+)/C(-)). Proliferation and IFN-gamma production were significantly greater in lymphocyte cultures from S(+)/C(-) individuals compared to C(+) individuals (P0.001 and P0.05, respectively). These findings demonstrate that compared to C(+) patients, individuals with subclinical melioidosis have a stronger CMI response to B. pseudomallei antigens in vitro. Such a response may be essential for protection against disease progression.

The ecology and behavior of most of the 11 known members of the Anopheles punctulatus group remain unresolved and only the morphologic species An. farauti, An. koliensis, and An. punctulatus are known as vectors of malaria in Papua New Guinea. Of 1,582 mosquitoes examined morphologically, 737 were identified as An. farauti s.l., 719 as An. koliensis, and 126 as An. punctulatus. All specimens identified morphologically as An. punctulatus were shown to be An. punctulatus by polymerase chain reaction-restriction fragment length polymorphism analysis, but the An. farauti and An. koliensis morphotypes consisted of three or more species including An. farauti s.s., An. farauti No. 2, and An. farauti No. 4. The biting cycles and role in malaria transmission of some of these species are described here for the first time. We also show evidence that An. koliensis could be a sub-complex of two or more species. The epidemiologic implications of our findings are discussed.

A study was conducted in Papua New Guinea to analyze Plasmodium falciparum drug resistance polymorphisms in patients presenting with resistant malaria. One hundred ninety-nine P. falciparum-positive patients were recruited at two sites, Madang and Maprik. Exposure to the 4-aminoquinolines chloroquine and amodiaquine was uniformly high, at 84% overall. However, 59% of these were taken in various combinations of sulfadoxine/pyrimethamine and/or primaquine and/or quinine. Two markers for 4-aminoquinoline resistance, P. falciparum chloroquine resistance transporter 76T and P. falciparum multidrug resistance 1, were fixed in the population and two markers for pyrimethamine resistance, dihydrofolate reductase (dhps) 59R and 108N, were found at moderate to high levels, overall 60% and 75%, respectively. No polymorphisms in dhps associated with sulfadoxine resistance were present. Differences between the two sites are analyzed. The study period encompasses a change in standard malaria treatment policy. These findings stress the need for regular monitoring of the effects of standard drug treatment of uncomplicated malaria in Papua New Guinea.

Through a collaborative project led by the Papua New Guinea Institute of Medical Research (PNGIMR), Papua New Guinea has a significant role in the global effort to develop a malaria vaccine, ensuring that the malaria patterns in Asia and the Pacific region are considered in vaccine development strategies. Some of the major perspectives and achievements of the program are discussed here, one of the most successful being the trial of Combination B, a vaccine comprising three asexual blood-stage proteins [merozoite surface protein (MSP)1, MSP2 and ring-infected erythrocyte surface antigen (RESA)], which led to a considerable reduction of parasite density in the immunized children.

The Papua New Guinea Institute of Medical Research (PNGIMR) is one of the most respected health research institutions in the developing world, and its studies of the local health problems of PNG have consistently had international relevance. This article examines the structural and philosophical factors that have enabled the success of the PNGIMR, and presents the PNGIMR approach to research as a potential model for other disease-endemic countries. An overview of PNGIMR research into malaria and filariasis is given with selected examples as an introduction to a Trends in Parasitology series on health research in Papua New Guinea.

Aims: To determine in children with meningitis whether there is any difference in mortality and neurological sequelae using chloramphenicol as first line treatment, with a change to ceftriaxone if chloramphenicol resistance is shown in vitro, compared to using ceftriaxone as first line treatment, with a change to chloramphenicol if there is no evidence of in vitro resistance. Methods: An observational study with a retrospective control group nested within a randomised trial of fluid management for bacterial meningitis where clinical care was standardised. Chloramphenicol is standard treatment for bacterial meningitis in Papua New Guinea. In the first 150 cases we used chloramphenicol and only changed treatment to ceftriaxone if chloramphenicol resistance for cerebrospinal fluid isolates was proved. After finding 20% of Haemophilus influenzae were resistant to chloramphenicol, and that most affected children had poor outcomes, we changed to an alternative strategy. In the next 196 cases first line treatment was ceftriaxone and treatment was changed to chloramphenicol if the isolated bacteria were found to be susceptible. Results: When chloramphenicol was used as first line treatment for meningitis followed by ceftriaxone when in vitro resistance was shown, there was invariably a very poor outcome in chloramphenicol resistant disease (71% of children died or had severe neurological complications). Using ceftriaxone as first line treatment was effective in reducing mortality and neurological sequelae from chloramphenicol resistant Haemophilus influenzae type (71% v 9%, relative risk 0.13; 95% CI 0.02 to 0.87; p = 0.013). Changing to chloramphenicol if there was no evidence of in vitro resistance was less than half the cost of empirical use of ceftriaxone for a full course for all children with meningitis. Conclusions: Using a third generation cephalosporin as first line treatment is effective in dealing with the problem of poor outcomes from meningitis due to Haemophilus influenzae that is resistant to chloramphenicol, and a strategy of changing to chloramphenicol if in vitro susceptibility is shown will reduce the use of expensive third generation cephalosporins without comprising on clinical outcomes. This highlights the urgent need to reduce the costs of third generation cephalosporins, to improve bacteriological services in developing countries, and to introduce effective and affordable vaccines against H influenzae and Streptococcus pneumoniae .

To achieve disease control objectives, country programmes need effective tools for prevention, diagnosis, and treatment, but the current pharmaceutical profit-driven motive neglects “tropical diseases.” Over the 40 years of its existence, TDR has used a range of approaches to promote the development and effective use of new products. Many were successful and contributed to identifying, testing, registering, and implementing tools for tropical disease, but lessons can also be learnt from those which failed or proved not sustainable. This paper reviews examples of TDR approaches and contributions to drug discovery research and development (R&D) and the optimisation of existing treatments against the backdrop of vast changes in the R&D landscape for infectious diseases of poverty. New funders and organizations are now available to conduct product R&D, allowing TDR to reduce its own R&D role to one of facilitation and promotion of an environment more conducive to innovation in R&D and access to the resulting products. Our focus is now more on intervention and implementation research to generate the evidence needed for decisions on where, when, and how products can best be incorporated into national health services for maximum benefit to the people in need.

From the beginning of the 20th century, the industrialized “North” made incredible improvements in public health that reduced the threat of infectious diseases and increased overall health. Unfortunately, this was not the case in many other countries [1]. By the 1970s, major disease-control initiatives in low- and middle-income countries, which were driven vertically by donors, were having mixed results, and private-sector pharmaceutical firms had little incentive to invest in the drugs and tools needed by countries that could ill afford the research and development (R&D) costs. In April of 1974, the 27th session of the World Health Assembly called for the “intensification of activities in tropical disease research” and the “strengthening of research and training activities”, particularly in developing countries [2]. Within two months, the World Health Organization (WHO)Advisory Committee on Medical Research met and discussed the need to “coordinate and stimulate biomedical research through bilateral and multinational arrangements,” and to apply “advances in knowledge in basic biology to urgent medical and public health problems.” They recommended an “expanded WHO programme for research and training related to tropical communicable diseases” [2]. By November of that year, TDR, the Special Programme for Research and Training in Tropical Diseases, was in operation. The main principles underpinning the formation of TDR are just as relevant today as they were when the Programme was established: to promote and conduct research equitably and to provide access to this knowledge and the resulting tools to the most vulnerable and hard-to-reach people. It has been 40 years since that beginning, and many lessons have since been learned. This special collection of seven articles (including this one) is designed to share those lessons—what worked, what did not, and how the Programme has evolved to meet the changing needs of both researchers and the research fields. What has changed is the type of research supported, the way it was conducted, and even the diseases covered. As the needs in the countries evolved, so too did the Programme, which is explained in more detail in the following articles.

Pulsed-field gel electrophoresis (PFGE) of Xba I-digested chromosomal DNA was performed on 133 strains of Salmonella enterica serovar Typhi obtained from Papua New Guinea, with the objective of assessing the temporal variation of these strains. Fifty-two strains that were isolated in 1992 and 1994 were of one phage type, D2, and only two predominant PFGE profiles, X1 and X2, were present. Another 81 strains isolated between 1997 and 1999 have shown divergence, with four new phage types, UVS I ( n = 63), UVS ( n = 5), VNS ( n = 4), and D1 ( n = 9), and more genetic variability as evidenced by the multiple and new PFGE Xba I profiles (21 profiles; Dice coefficient, F = 0.71 to 0.97). The two profiles X1 and X2 have remained the stable, dominant subtypes since 1992. Cluster analysis based on the unweighted pair group method using arithmetic averages algorithm identifies two main clusters (at 87% similarity), indicating that the divergence of the PFGE subtypes was probably derived from some genomic mutations of the X1 and X2 subtypes. The majority of isolates were from patients with mild and moderate typhoid fever and had various Xba I profiles. A single isolate from a patient with fatal typhoid fever had a unique X11 profile, while four of six isolates from patients with severe typhoid fever had the X1 pattern. In addition, 12 paired serovar Typhi isolates recovered from the blood and fecal swabs of individual patients exhibited similar PFGE patterns, while in another 11 individuals paired isolates exhibited different PFGE patterns. Three pairs of isolates recovered from three individuals had different phage types and PFGE patterns, indicating infection with multiple strains. The study reiterates the usefulness of PFGE in assessing the genetic diversity of S. enterica serovar Typhi for both long-term epidemiology and in vivo stability and instability within an individual patient.

Now is a good time to reconsider research priorities as 2015 approaches, the target date originally set for elimination of visceral leishmaniasis. Visceral leishmaniasis is one of the most deadly parasitic diseases and disproportionately affects the poorest and most vulnerable populations. An estimated 200 000–400 000 people contract visceral leishmaniasis every year in developing countries. Spread by sandflies, visceral leishmaniasis can be fought with existing interventions, including treatment and vector control, but, similarly to every other human parasitic disease, no effective vaccine exists.

Background As Plasmodium falciparum and Plasmodium vivax co-exist in most malaria-endemic regions outside sub-Saharan Africa, malaria control strategies in these areas must target both species in order to succeed. Population genetic analyses can predict the effectiveness of interventions including vaccines, by providing insight into patterns of diversity and evolution. The aim of this study was to investigate the population genetics of leading malaria vaccine candidate AMA1 in sympatric P. falciparum and P. vivax populations of Papua New Guinea (PNG), an area of similarly high prevalence (Pf = 22.3 to 38.8%, Pv = 15.3 to 31.8%). Methods A total of 72 Pfama1 and 102 Pvama1 sequences were collected from two distinct areas, Madang and Wosera, on the highly endemic PNG north coast. Results Despite a greater number of polymorphic sites in the AMA1 genes of P. falciparum (Madang = 52; Wosera = 56) compared to P. vivax (Madang = 36, Wosera = 34), the number of AMA1 haplotypes, haplotype diversity (Hd) and recombination (R) was far lower for P. falciparum (Madang = 12, Wosera = 20; Hd ≤0.92, R ≤45.8) than for P. vivax (Madang = 50, Wosera = 38; Hd = 0.99, R = ≤70.9). Balancing selection was detected only within domain I of AMA1 for P. vivax, and in both domains I and III for P. falciparum. Conclusions Higher diversity in the genes encoding P. vivax AMA1 than in P. falciparum AMA1 in this highly endemic area has important implications for development of AMA1-based vaccines in PNG and beyond. These results also suggest a smaller effective population size of P. falciparum compared to P. vivax, a finding that warrants further investigation. Differing patterns of selection on the AMA1 genes indicate that critical antigenic sites may differ between the species, highlighting the need for independent investigations of these two leading vaccine candidates.

Plasmodium falciparum malaria is a major global health problem that is being targeted for progressive elimination. Knowledge of local disease transmission patterns in endemic countries is critical to these elimination efforts. To investigate fine-scale patterns of malaria transmission, we have compared repertoires of rapidly evolving var genes in a highly endemic area. A total of 3680 high-quality DBLα-sequences were obtained from 68 P. falciparum isolates from ten villages spread over two distinct catchment areas on the north coast of Papua New Guinea (PNG). Modelling of the extent of var gene diversity in the two parasite populations predicts more than twice as many var gene alleles circulating within each catchment (Mugil = 906; Wosera = 1094) than previously recognized in PNG (Amele = 369). In addition, there were limited levels of var gene sharing between populations, consistent with local parasite population structure. Phylogeographic analyses demonstrate that while neutrally evolving microsatellite markers identified population structure only at the catchment level, var gene repertoires reveal further fine-scale geospatial clustering of parasite isolates. The clustering of parasite isolates by village in Mugil, but not in Wosera was consistent with the physical and cultural isolation of the human populations in the two catchments. The study highlights the microheterogeneity of P. falciparum transmission in highly endemic areas and demonstrates the potential of var genes as markers of local patterns of parasite population structure.

Parasite sequestration in the placenta is a key feature of infection by Plasmodium falciparum during pregnancy and is associated with severe adverse outcomes for both mother and baby. Here, James Beeson and colleagues draw together the findings of recent studies on parasite mechanisms that mediate this process. They review evidence for novel parasite variants that appear able to evade pre-existing immunity, for the adhesion of P. falciparum-infected erythrocytes to placental glycosaminoglycans (and the molecular basis of these parasite properties) and for the expression of var genes encoding the variant antigen and adhesive ligand P. falciparum-erythrocyte membrane protein 1 (PfEMP1).

Antibodies that bind to antigens expressed on the merozoite form of the malaria parasite can inhibit parasite growth by preventing merozoite invasion of red blood cells. Inhibitory antibodies are found in the sera of malaria-immune individuals, however, the specificity of those that are important to this process is not known. In this paper, we have used allelic replacement to construct a Plasmodium falciparum parasite line that expresses the complete COOH-terminal fragment of merozoite surface protein (MSP)-119 from the divergent rodent malaria P. chabaudi. By comparing this transfected line with parental parasites that differ only in MSP-119, we show that antibodies specific for this domain are a major component of the inhibitory response in P. falciparum–immune humans and P. chabaudi–immune mice. In some individual human sera, MSP-119 antibodies dominated the inhibitory activity. The finding that antibodies to a small region of a single protein play a major role in this process has important implications for malaria immunity and is strongly supportive of further understanding and development of MSP-119–based vaccines.

Background The Plasmodium vivax Apical Membrane Antigen 1 (PvAMA1) is a promising malaria vaccine candidate, however it remains unclear which regions are naturally targeted by host immunity and whether its high genetic diversity will preclude coverage by a monovalent vaccine. To assess its feasibility as a vaccine candidate, we investigated the global population structure of PvAMA1. Methodology and Principal Findings New sequences from Papua New Guinea (PNG, n = 102) were analysed together with published sequences from Thailand (n = 158), India (n = 8), Sri Lanka (n = 23), Venezuela (n = 74) and a collection of isolates from disparate geographic locations (n = 8). A total of 92 single nucleotide polymorphisms (SNPs) were identified including 22 synonymous SNPs and 70 non-synonymous (NS) SNPs. Polymorphisms and signatures of balancing (positive Tajima's D and low FST values) selection were predominantly clustered in domain I, suggesting it is a dominant target of protective immune responses. To estimate global antigenic diversity, haplotypes comprised of (i) non-singleton (n = 40) and (ii) common (≥10% minor allele frequency, n = 23) polymorphic amino acid sites were then analysed revealing a total of 219 and 210 distinct haplotypes, respectively. Although highly diverse, the 210 haplotypes comprised of only common polymorphisms were grouped into eleven clusters, however substantial geographic differentiation was observed, and this may have implications for the efficacy of PvAMA1 vaccines in different malaria-endemic areas. The PNG haplotypes form a distinct group of clusters not found in any other geographic region. Vaccine haplotypes were rare and geographically restricted, suggesting potentially poor efficacy of candidate PvAMA1 vaccines. Conclusions It may be possible to cover the existing global PvAMA1 diversity by selection of diverse alleles based on these analyses however it will be important to first define the relationships between the genetic and antigenic diversity of this molecule., Author Summary Traditionally misclassified as benign and neglected as a research priority, it is now understood that P. vivax is an increasingly important cause of human malaria. This important human pathogen poses an enormous obstacle to malaria control and elimination efforts due its broad geographic distribution, ability to cause recurring episodes of malaria after long periods of inactivity and extreme biodiversity. Vaccines are an essential component of global malaria control and elimination campaigns but the diversity of malaria antigens is thought to be a major cause of vaccine failure. Furthermore, at present the majority of current vaccine research is directed toward P. falciparum. The aims of this study were to investigate the global diversity of the P. vivax vaccine candidate, Apical Membrane Antigen 1 (PvAMA1), to determine the feasibility of designing a globally effective PvAMA1 vaccine and to determine which region of PvAMA1 is targeted by host immune responses, in order to identify the most promising vaccine candidates. We report that PvAMA1 diversity is extremely high, and that PvAMA1 domain I is a dominant target of host immune responses. These analyses of PvAMA1 diversity from several geographic regions provide a framework to guide development of a broadly efficacious P. vivax vaccine.

High levels of genetic diversity in Plasmodium falciparum populations are an obstacle to malaria control. Here, we investigate the relationship between local variation in malaria epidemiology and parasite genetic diversity in Papua New Guinea (PNG). Cross-sectional malaria surveys were performed in 14 villages spanning four distinct malaria-endemic areas on the north coast, including one area that was sampled during the dry season. High-resolution msp2 genotyping of 2,147 blood samples identified 761 P. falciparum infections containing a total of 1,392 clones whose genotypes were used to measure genetic diversity. Considerable variability in infection prevalence and mean multiplicity of infection was observed at all of the study sites, with the area sampled during the dry season showing particularly striking local variability. Genetic diversity was strongly associated with multiplicity of infection but not with infection prevalence. In highly endemic areas, differences in infection prevalence may not translate into a decrease in parasite population diversity.

Background Approximately 826,000 children, mostly young infants, die annually from invasive pneumococcal disease. A 6-10-14-week schedule of pneumococcal conjugate vaccine (PCV) is efficacious but neonatal PCV may provide earlier protection and better coverage. We conducted an open randomized controlled trial in Papua New Guinea to compare safety, immunogenicity and priming for memory of 7-valent PCV (PCV7) given in a 0-1-2-month (neonatal) schedule with that of the routine 1-2-3-month (infant) schedule. Methods We randomized 318 infants at birth to receive PCV7 in the neonatal or infant schedule or no PCV7. All infants received 23-valent pneumococcal polysaccharide vaccine (PPV) at age 9 months. Serotype-specific serum IgG for PCV7 (VT) serotypes and non-VT serotypes 2, 5 and 7F were measured at birth and 2, 3, 4, 9, 10 and 18 months of age. Primary outcomes were geometric mean concentrations (GMCs) and proportions with concentration ≥0.35 µg/ml of VT serotype-specific pneumococcal IgG at age 2 months and one month post-PPV. Results We enrolled 101, 105 and 106 infants, respectively, into neonatal, infant and control groups. Despite high background levels of maternally derived antibody, both PCV7 groups had higher GMCs than controls at age 2 months for serotypes 4 (p

A broadly effective malaria vaccine is a missing component of the practical tools needed to control and eventually eliminate malaria. For more than 50 years malaria researchers have been searching for a strategy that provides long lasting protection against a broad range of parasite strains. Many different approaches have been tested including whole parasite and subunit vaccines composed of one or more parasite surface proteins that are naturally targeted by the host immune response.

Traditionally, infection with Plasmodium vivax was thought to be benign and self-limiting, however, recent evidence has demonstrated that infection with P. vivax can also result in severe illness and death. Research into P. vivax has been relatively neglected and much remains unknown regarding the biology, pathogenesis and epidemiology of this parasite. One of the fundamental factors governing transmission and immunity is parasite diversity. An understanding of parasite population genetic structure is necessary to understand the epidemiology, diversity, distribution and dynamics of natural P. vivax populations. In addition, studying the population structure of genes under immune selection also enables investigation of the dynamic interplay between transmission and immunity, which is crucial for vaccine development. A lack of knowledge regarding the transmission and spread of P. vivax has been particularly highlighted in areas where malaria control and elimination programmes have made progress in reducing the burden of Plasmodium falciparum, yet P. vivax remains as a substantial obstacle. With malaria elimination back on the global agenda, mapping of global and local P. vivax population structure is essential prior to establishing goals for elimination and the roll-out of interventions. A detailed knowledge of the spatial distribution, transmission and clinical burden of P. vivax is required to act as a benchmark against which control targets can be set and measured. This paper presents an overview of what is known and what is yet to be fully understood regarding P. vivax population genetics, as well as the importance and application of P. vivax population genetics studies.

Ivo Mueller and colleagues examined the association of Southeast Asian ovalocytosis with Plasmodium vivax infection by genotyping 1975 children enrolled in three independent epidemiological studies conducted in the Madang area of Papua New Guinea and assessing P. vivax infection and disease in the children., Background The erythrocyte polymorphism, Southeast Asian ovalocytosis (SAO) (which results from a 27-base pair deletion in the erythrocyte band 3 gene, SLC4A1Δ27) protects against cerebral malaria caused by Plasmodium falciparum; however, it is unknown whether this polymorphism also protects against P. vivax infection and disease. Methods and Findings The association between SAO and P. vivax infection was examined through genotyping of 1,975 children enrolled in three independent epidemiological studies conducted in the Madang area of Papua New Guinea. SAO was associated with a statistically significant 46% reduction in the incidence of clinical P. vivax episodes (adjusted incidence rate ratio [IRR] = 0.54, 95% CI 0.40–0.72, p90% binding inhibition) P. vivax Duffy binding protein–specific binding inhibitory antibodies were observed significantly more often in sera from SAO than non-SAO children (SAO, 22.2%; non-SAO, 6.7%; p = 0.008). Conclusions In three independent studies, we observed strong associations between SAO and protection against P. vivax malaria by a mechanism that is independent of the Duffy antigen. P. vivax malaria may have contributed to shaping the unique host genetic adaptations to malaria in Asian and Oceanic populations. Please see later in the article for the Editors' Summary., Editors' Summary Background Hereditary blood disorders are widely prevalent in different regions around the world and the type of disorder depends on the population gene pool. For example, sickle cell disease is indigenous to sub-Saharan Africa, and Southeast Asian ovalocytosis (SAO), as the name suggests, to Southeast Asia and the South West Pacific, particularly Malaysia and Papua New Guinea. In SAO, the red blood cells (erythrocytes) are a different shape (elliptical) from the usual biconcave disc shape due to a genetic defect (caused by band 3 deletion SLC4A1Δ27) in the red blood cell membrane. This defect is carried by up to 35% of people living on the coasts of Papua New Guinea, and as these areas match high malaria endemic areas, it is thought that carrying this defect is associated with improved survival against malaria in these populations—some studies have suggested that SAO is associated with complete protection against cerebral malaria but not other forms of malaria caused by the same type of parasite—P. falciparum. Why Was This Study Done? Although P. falciparum gains most attention by the international health community as it causes the most severe types of malaria, recent epidemiological studies suggest that malaria caused by P. vivax can also cause severe illness in some areas of the world where it is highly prevalent. Furthermore, detailed genetic and laboratory studies have suggested that the genetic defect associated with SAO may actually protect against infection from P. vivax malaria. So in this study, the researchers examined the relationship of the SAO genetic defect and P. vivax malaria by doing genetic tests on children in Papua New Guinea—an area in which both conditions are widely prevalent. What Did the Researchers Do and Find? The researchers performed genetic tests for the SAO defect in 1,975 children in the Madang area of Papua New Guinea who were participating in three separate malaria studies that were conducted over different time periods: (i) a cohort of 1,121 infants aged 3–21 months participating in a clinical drug trial of intermittent preventative treatment of malaria; (ii) a case-control study of 318 children with severe malaria aged 10 years and under; and (iii) a cohort of 206 children aged 5–14 years who took part in a prospective study to evaluate the time of reinfection with all forms of malaria. Given the different nature of these studies, for example, the effect of intermittent treatment for which the researchers had to make statistical adjustments, the researchers analysed the presence of the SAO genetic defect and the incidence of all forms of malaria separately to calculate the association with SAO and malaria in the participants in each study. The researchers found that the SAO genetic defect present in 130 infants (11.6%) in the first study and 27 (13.1%) children in the third study. In the case-control study, the researchers found that 28 of the 330 controls (8.5%) had the SAO genetic defect compared to eight of 236 (3.4%) in children with P. falciparum single infections. Overall, the researchers found that the SAO genetic defect was associated with a 43% reduction in risk of clinical P. vivax episodes in the infants in the first study and a 52%–55% reduction in P. vivax reinfection in children in the third study. Furthermore, from the limited data from the second study, the researchers found that none of the children with P. vivax or mixed P. falciparum/P. vivax malaria had the SAO defect, which may indicate a protective effect. What Do These Findings Mean? These findings suggest that the SAO genetic defect (SLC4A1Δ27) may have a protective effect against malaria caused by P. vivax in infants and children of different ages in Papua New Guinea. However, although it seems likely that SAO may alter the ability of the malarial parasite to develop within the red blood cell, this study sheds no further light on the way in which the SAO genetic defect may protect against P. vivax infection and disease and so further studies are needed to investigate possible mechanisms. Importantly, these findings suggest that future studies investigating genetic adaptation of diverse populations around the world, particularly in the Asian Pacific region, should include all forms of human malaria, such as P. vivax, and not exclusively focus on P. falciparum. Additional Information Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001305. Wikipedia has information on Southeast Asian Ovalocytosis (note that Wikipedia is a free online encyclopedia that anyone can edit; available in several languages) WHO provides information on malaria The US Centers for Disease Control and Prevention provide information on malaria (in English and Spanish) MedlinePlus provides links to additional information on malaria and on ovalocytosis

A three-arm randomized trial conducted among infants in Papua New Guinea estimates the preventive effect against malaria episodes of intermittent preventive treatment, in an area where children are exposed to both falciparum and vivax malaria., Background Intermittent preventive treatment in infants (IPTi) has been shown in randomized trials to reduce malaria-related morbidity in African infants living in areas of high Plasmodium falciparum (Pf) transmission. It remains unclear whether IPTi is an appropriate prevention strategy in non-African settings or those co-endemic for P. vivax (Pv). Methods and Findings In this study, 1,121 Papua New Guinean infants were enrolled into a three-arm placebo-controlled randomized trial and assigned to sulfadoxine-pyrimethamine (SP) (25 mg/kg and 1.25 mg/kg) plus amodiaquine (AQ) (10 mg/kg, 3 d, n = 374), SP plus artesunate (AS) (4 mg/kg, 3 d, n = 374), or placebo (n = 373), given at 3, 6, 9 and 12 mo. Both participants and study teams were blinded to treatment allocation. The primary end point was protective efficacy (PE) against all episodes of clinical malaria from 3 to 15 mo of age. Analysis was by modified intention to treat. The PE (compared to placebo) against clinical malaria episodes (caused by all species) was 29% (95% CI, 10–43, p≤0.001) in children receiving SP-AQ and 12% (95% CI, −11 to 30, p = 0.12) in those receiving SP-AS. Efficacy was higher against Pf than Pv. In the SP-AQ group, Pf incidence was 35% (95% CI, 9–54, p = 0.012) and Pv incidence was 23% (95% CI, 0–41, p = 0.048) lower than in the placebo group. IPTi with SP-AS protected only against Pf episodes (PE = 31%, 95% CI, 4–51, p = 0.027), not against Pv episodes (PE = 6%, 95% CI, −24 to 26, p = 0.759). Number of observed adverse events/serious adverse events did not differ between treatment arms (p>0.55). None of the serious adverse events were thought to be treatment-related, and the vomiting rate was low in both treatment groups (1.4%–2.0%). No rebound in malaria morbidity was observed for 6 mo following the intervention. Conclusions IPTi using a long half-life drug combination is efficacious for the prevention of malaria and anemia in infants living in a region highly endemic for both Pf and Pv. Trial registration ClinicalTrials.gov NCT00285662 Please see later in the article for the Editors' Summary, Editors' Summary Background Malaria is a major global public health problem. Half the world's population is at risk of this parasitic disease, which kills about one million people (mainly young children in sub-Saharan Africa) every year. Most of these deaths are caused by Plasmodium falciparum but P. vivax, the commonest and most widely distributed malaria parasite, is a major cause of malaria-related morbidity (illness and death) in many of the tropical and subtropical regions of the world where malaria is endemic (always present). Malaria is transmitted to people through the bites of night-flying mosquitoes. It can be prevented by controlling the mosquitoes that spread the parasite and by sleeping under insecticide-treated nets to avoid mosquito bites. Prompt treatment of malaria with antimalarial drugs can also reduce malaria transmission. In addition, intermittent preventative treatment (IPT)—the treatment of symptom-free individuals with full therapeutic courses of antimalarial drugs at fixed intervals regardless of their infection status—has been shown to reduce malaria-related morbidity among pregnant women in malaria-endemic areas and among African infants living in areas of high P. falciparum transmission. Why Was This Study Done? The World Health Organization recently recommended that, in Africa, IPT should be given during infancy (called IPTi) at the same time as routine immunizations. Because the studies on which this recommendation is based were all carried out in sub-Saharan Africa, in populations where P. falciparum is the predominant parasite and P. vivax is uncommon, it is not known whether IPTi would be an appropriate prevention strategy in non-African settings or in regions where both P. falciparum and P. vivax are endemic. In this randomized placebo-controlled trial, the researchers investigate the efficacy of IPTi in infants living in an area of Papua New Guinea where P. falciparum and P. vivax are both highly endemic. In a randomized placebo-controlled trial, the effects of an intervention and of a placebo (dummy) intervention are compared in groups of individuals chosen through the play of chance. What Did the Researchers Do and Find? The researchers assigned more than 1,000 infants to receive sulfadoxine/pyrimethamine (SP) plus amodiaquine (AQ) (SP and AQ are long-lasting antimalarial drugs), SP plus artesunate (AS) (AS is a short-lasting antimalarial), or placebo at 3, 6, 9, and 12 months old. They recorded the number of malaria episodes that occurred among the children between the ages of 3 and 15 months. Then, by comparing the number of episodes occurring among the children receiving SP-AS or SP-AQ with the number occurring among the children receiving placebo, the researchers calculated the protective efficacy of the two drug combinations over the study period. The protective efficacy of IPTi against all clinical malaria episodes (P. falciparum and P. vivax combined) was 29% for SP-AQ, but SP-AS was not associated with a statistically significant reduction in all malaria episodes as compared to placebo. For the two species of malaria separately, the incidence of P. falciparum malaria was 35% lower among the children receiving SP-AQ than among the children receiving placebo, whereas the incidence of P. vivax was reduced by 23%; IPTi with SP-AS provided protection only against P. falciparum malaria (protective efficacy 31%). Importantly, the number of adverse events (possible drug side effects) was similar in all the treatment arms, none of the severe adverse events were treatment-related, and there was no rebound in malaria-related morbidity for six months following the end of the intervention. What Do These Findings Mean? These findings show that IPTi using a combination of long-lasting antimalarial drugs (SP-AQ) can effectively and safely prevent malaria in a non-African population living in a region where P. falciparum and P. vivax are both highly endemic. Importantly, they also show that IPTi with SP-AQ can prevent both P. falciparum and P. vivax malaria. For Papua New Guinea, these findings suggest that SP-AQ is an appropriate drug choice for IPTi, particularly since the replacement of SP-AQ by artemether-lumefantrine as the national first line treatment for malaria will reduce the selection pressure for resistance against SP and AQ. However, although these finding provide proof-of-principle evidence for the efficacy and safety of IPTi, further studies are needed to identify the most effective combinations of long-lasting antimalarial drugs for use in IPTi in other malaria-endemic regions. Additional Information Please access these web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001195. Information is available from the World Health Organization on malaria (in several languages); the 2011 World Malaria Report provides details of the current global malaria situation; and the WHO policy recommendation on IPTi for P. falciparum malaria control in Africa is available The US Centers for Disease Control and Prevention provide information on malaria (in English and Spanish), including a selection of personal stories about malaria Information is available from the Roll Back Malaria Partnership on the global control of malaria, including a fact sheet about malaria in children and information on malaria in Papua New Guinea The IPTi Consortium was established to evaluate IPTi and inform public health policy making The Malaria Vaccine Initiative has a fact sheet on P. vivax malaria Vivaxmalaria.com provides information about P. vivax MedlinePlus provides links to additional information on malaria (in English and Spanish)

Background The South West Pacific nation of Papua New Guinea has intense year round transmission of Plasmodium falciparum on the coast and in the low-lying inland areas. Local heterogeneity in the epidemiology of malaria suggests that parasites from multiple locations will need to be surveyed to define the population biology of P. falciparum in the region. This study describes the population genetics of P. falciparum in thirteen villages spread over four distinct catchment areas of Papua New Guinea. Methods Ten microsatellite loci were genotyped in 318 P. falciparum isolates from the parasite populations of two inland catchment areas, namely Wosera (number of villages (n) = 7) and Utu (n = 1) and; and two coastal catchments, Malala (n = 3) and Mugil (n = 3). Analysis of the resultant multilocus haplotypes was done at different spatial scales (2-336 km) to define the genetic diversity (allelic richness and expected heterozygosity), linkage disequilibrium and population structure throughout the study area. Results Although genetic diversity was high in all parasite populations, it was also variable with a lower allelic richness and expected heterozygosity for inland populations compared to those from the more accessible coast. This variability was not correlated with two proxy measures of transmission intensity, the infection prevalence and the proportion multiple infections. Random associations among the microsatellite loci were observed in all four catchments showing that a substantial degree of out-crossing occurs in the region. Moderate to very high levels of population structure were found but the amount of genetic differentiation (F ST ) did not correlate with geographic distance suggesting that parasite populations are fragmented. Population structure was also identified between villages within the Malala area, with the haplotypes of one parasite population clustering with the neighbouring catchment of Mugil. Conclusion The observed population genetics of P. falciparum in this region is likely to be a consequence of the high transmission intensity combined with the isolation of human and vector populations, especially those located inland and migration of parasites via human movement into coastal populations. The variable genetic diversity and population structure of P. falciparum has important implications for malaria control strategies and warrants further fine scale sampling throughout Papua New Guinea.

BACKGROUND: The hypothesis is that hemoglobin-based metrics are useful tools for estimating malaria endemicity and for monitoring malaria control strategies. The aim of this study is to compare population hemoglobin mean and anemia prevalence to established indicators of malaria endemicity, including parasite rates, rates of enlarged spleens in children, and records of (presumptive) malaria diagnosis among populations living with different levels of malaria transmission. METHODOLOGY/PRINCIPAL FINDINGS: Convenience sample, multisite cross-sectional household surveys conducted in Papua New Guinea. Correlations (r(2)) between population Hb mean and anemia prevalence and altitude, parasite rate, and spleen rate were investigated in children ages 2 to 10 years, and in the general population; 21,664 individuals from 156 different communities were surveyed. Altitude ranged from 5 to 2120 meters. In young children, correlations between altitude and parasite rate, population Hb mean, anemia prevalence, and spleen rate were high (r(2): -0.77, 0.73, -0.81, and -0.68; p1500 m (p

The extensive diversity of Plasmodium falciparum antigens is a major obstacle to a broadly effective malaria vaccine but population genetics has rarely been used to guide vaccine design. We have completed a meta-population genetic analysis of the genes encoding ten leading P. falciparum vaccine antigens, including the pre-erythrocytic antigens csp, trap, lsa1 and glurp; the merozoite antigens eba175, ama1, msp's 1, 3 and 4, and the gametocyte antigen pfs48/45. A total of 4553 antigen sequences were assembled from published data and we estimated the range and distribution of diversity worldwide using traditional population genetics, Bayesian clustering and network analysis. Although a large number of distinct haplotypes were identified for each antigen, they were organized into a limited number of discrete subgroups. While the non-merozoite antigens showed geographically variable levels of diversity and geographic restriction of specific subgroups, the merozoite antigens had high levels of diversity globally, and a worldwide distribution of each subgroup. This shows that the diversity of the non-merozoite antigens is organized by physical or other location-specific barriers to gene flow and that of merozoite antigens by features intrinsic to all populations, one important possibility being the immune response of the human host. We also show that current malaria vaccine formulations are based upon low prevalence haplotypes from a single subgroup and thus may represent only a small proportion of the global parasite population. This study demonstrates significant contrasts in the population structure of P. falciparum vaccine candidates that are consistent with the merozoite antigens being under stronger balancing selection than non-merozoite antigens and suggesting that unique approaches to vaccine design will be required. The results of this study also provide a realistic framework for the diversity of these antigens to be incorporated into the design of next-generation malaria vaccines.