Malaria still remains a public health problem in some districts of Bhutan despite marked reduction of cases in last few years. To strengthen the country's prevention and control measures, this study was carried out to develop forecasting and prediction models of malaria incidence in the endemic districts of Bhutan using time series and ARIMAX. This study was carried out retrospectively using the monthly reported malaria cases from the health centres to Vector-borne Disease Control Programme (VDCP) and the meteorological data from Meteorological Unit, Department of Energy, Ministry of Economics. Time series analysis was performed on monthly malaria cases, from 1994 to 2008, in seven malaria endemic districts.

3/09/2010  from Malaria Journal     Read More

Efforts to ease administration and enhance acceptability of the oral anti-malarial artemether-lumefantrine (A-L) crushed tablet to infants and children triggered the development of a novel dispersible tablet of A-L. During early development of this new formulation, two studies were performed in healthy subjects, one to evaluate the palatability of three flavours of A-L, and a second one to compare the bioavailability of active principles between the dispersible tablet and the tablet (administered crushed and intact). Study 1 was performed in 48 healthy schoolchildren in Tanzania. Within 1 day, all subjects tasted a strawberry-, orange- and cherry-flavoured oral A-L suspension for 10 seconds (without swallowing) in a randomized, single-blind, crossover fashion.

3/09/2010  from Malaria Journal     Read More

The United Nations forecasts that by 2050, more than 60% of the African population will live in cities. Thus, urban malaria is considered an important emerging health problem in that continent. Remote sensing (RS) and geographic information systems (GIS) are useful tools for addressing the challenge of assessing, understanding and spatially focusing malaria control activities. The objectives of the present study were to use high spatial resolution SPOT (Satellite Pour l'Observation de la Terre) satellite images to identify some urban environmental factors in Dakar associated with Anopheles arabiensis densities, to assess the persistence of these associations and to describe spatial changes in at-risk environments using a decadal time scale.

3/09/2010  from Malaria Journal     Read More

Malaria remains one of the world's greatest killers and a vaccine is urgently required. There are no established correlates of protection against malaria either for natural immunity to the disease or for immunity conferred by candidate malaria vaccines. The RTS,S/AS02A vaccine offers significant partial efficacy against malaria. mRNA expression of five key cytokines interferon-gamma (IFN-?), monokine induced by gamma (MIG), interleukin-10 (IL-10), transforming growth factor-β (TGF-β) and forkhead box P3 (FoxP3) in peripheral blood mononuclear cells were measured by real-time RT-PCR before and after vaccination with RTS,S/AS02A and Modified Vaccinia virus Ankara encoding the circumsporozoite protein (MVA-CS) in healthy malaria-naive adult volunteers.

3/09/2010  from PLoS     Read More

Pregnancy-associated malaria (PAM) is a serious consequence of the adhesion to the placental receptor chondroitin sulfate A (CSA) of Plasmodium falciparum-infected erythrocytes (PE) expressing the large cysteine-rich multi-domain protein var2CSA. Women become resistant to PAM, and develop strain-transcending immunity against CSA-binding parasites. The identification of var2CSA regions that could elicit broadly neutralizing and adhesion-blocking antibodies is a key step for the design of prophylactic vaccine strategies. Methodology Escherichia coli expressed var2CSA DBL domains were refolded and purified prior to immunization of mice and a goat.

3/09/2010  from PLoS     Read More

Insecticide-treated nets (ITNs) are regarded as one of the most effective strategies to prevent malaria in Africa. This study analyses the use and quality of nets owned by households in an area of high net coverage. A structured questionnaire on ownership and use of nets was administered to the households of individuals sampled from a local health centre in south Kisii district, Kenya. A physical inspection of all the nets in the households was done and their conditions recorded on spot check forms designed for that purpose. Of the 670 households surveyed, 95% owned at least one net. Only 59% of household residents slept under a net during the night prior to the survey.

2/09/2010  from Malaria Journal     Read More

Plasmodium falciparum is the most pathogenic human malaria parasite and its virulence has been linked to its capacity to express different adhesion proteins that enable the developing parasitized erythrocyte to bind to capillaries of the host, thereby avoiding removal by the spleen. Each parasite has approximately 60 genes encoding different versions of this adhesion protein, and a switch in surface display of these proteins enables the parasite to evade the immune system. Here we show that different variants of these binding proteins can be found expressed simultaneously on single infected red blood cells mediating binding to different endothelial receptors.

2/09/2010  from PLoS     Read More

Safety data regarding exposure to artemisinin-based combination therapy in pregnancy are limited. This prospective cohort study conducted in Zambia evaluated the safety of artemether-lumefantrine (AL) in pregnant women with malaria. Pregnant women attending antenatal clinics were assigned to groups based on the drug used to treat their most recent malaria episode (AL vs. sulphadoxine-pyrimethamine, SP). Safety was assessed using standard and pregnancy-specific parameters. Post-delivery follow-up was six weeks for mothers and 12 months for live births. Primary outcome was perinatal mortality (stillbirth or neonatal death within seven days after birth). Data from 1,001 pregnant women (AL n=495; SP n=506) and 933 newborns (AL n=466; SP n=467) showed: perinatal mortality (AL 4.2%; SP 5.

1/09/2010  from Malaria Journal     Read More

A combination of gene silencing and behavioral studies in the malaria vector mosquito Anopheles gambiae sheds light on the olfactory basis of DEET repulsion as well as reveals the role of another family of chemosensory receptors that facilitate olfaction in An. gambiae.

31/08/2010  from PLoS     Read More

The RTS,S/AS01E malaria candidate vaccine is being developed for immunization of African infants through the Expanded Program of Immunization (EPI). Conclusion.RTS,S/AS01E integrated in the EPI showed a favorable safety and immunogenicity evaluation.

30/08/2010  from Journal of Infectious Diseases     Read More

The current study was undertaken to determine the optimal wash-drying regimen and the effects of different washing procedures on the efficacy, and durability of four brands of newly introduced long-lasting insecticide-treated nets (LLINs) under tropical conditions. The results of this study suggest that washing and drying regimen influence the insecticidal activity of LLINs. The standard WHOPES washing protocol underestimates the amount of insecticide washed from LLINs compared to the abrasive washing procedures that are used in the field. This suggests that there is need to educate net users to adopt a more gentle washing procedure while handling LLINs. The education should accompany net distribution campaigns.

30/08/2010  from Malaria Journal     Read More

Mutations in the dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) genes of Plasmodium falciparum are associated with resistance to anti-folate drugs, most notably sulphadoxine-pyrimethamine (SP). Molecular studies document the prevalence of these mutations in parasite populations across the African continent. However, there is no systematic review examining the collective epidemiological significance of these studies. This meta-analysis attempts to: 1) summarize genotype frequency data that are critical for molecular surveillance of anti-folate resistance and 2) identify the specific challenges facing the development of future molecular databases.

30/08/2010  from Malaria Journal     Read More

Theoretical and experimental data support the geographic differentiation strategy as a valuable tool for detecting loci under selection. In the context of Plasmodium falciparum malaria, few populations have been studied, with limited genomic coverage. These data further validate the utility of geographic differentiation for identifying loci under strong positive selection, such as drug resistance loci. This study also provides frequencies of molecular makers of resistance in some overlooked populations.

30/08/2010  from Journal of Infectious Diseases     Read More

Background.The Thai-Cambodian border has been known as the origin of antimalarial drug resistance for the past 30 years. There is a highly diverse market for antimalarials in this area, and improved knowledge of drug pressure would be useful to target interventions aimed at reducing inappropriate drug use. The findings demonstrate that there is high drug pressure and that many people still seek treatment in the private and informal sector, where appropriate treatment is not guaranteed. Promotion of comprehensive behavioral change, communication, community-based mobilization, and advocacy are vital to contain the emergence and spread of parasite resistance against new antimalarials.

30/08/2010  from Journal of Infectious Diseases     Read More

Prompt and correct diagnosis of malaria is crucial for accurate epidemiological assessment and better case management, and while the gold standard of light microscopy is often available, it requires both expertise and time. Portable fluorescent microscopy using the CyScope(R) offers a potentially quicker, easier and more field-applicable alternative. This article reports on the strengths, limitations of this methodology and its diagnostic performance in cross-sectional surveys on young children and women of child-bearing age.

27/08/2010  from Malaria Journal     Read More

Entomopathogenic fungi infection on malaria vectors increases daily mortality rates and thus represents a control measure that could be used in integrated programmes alongside insecticide-treated bed nets (ITNs) and indoor residual spraying (IRS). Before entomopathogenic fungi can be integrated into control programmes, an effective delivery system must be developed. Both fungal isolates reduced mosquito survival on immediate exposure and up to 28 d after application. Conidia were more effective when applied on mud panels and cotton cloth compared with polyester netting. Cotton cloth and mud, therefore, represent potential substrates for delivering fungi to mosquitoes in the field.

27/08/2010  from Malaria Journal     Read More

Home management of malaria (HMM), promoting presumptive treatment of febrile children in the community, is advocated to improve prompt appropriate treatment of malaria in Africa. The cost-effectiveness of HMM is likely to vary widely in different settings and with the antimalarial drugs used. However, no data on the cost-effectiveness of HMM programmes are available. Methods/Principal Findings A Markov model was constructed to estimate the cost-effectiveness of HMM as compared to conventional care for febrile illnesses in children without HMM. The model was populated with data from Uganda, but is designed to be interactive, allowing the user to adjust certain parameters, including the antimalarials distributed.

27/08/2010  from PLoS     Read More

Integrated disease prevention in low resource settings can increase coverage, equity and efficiency in controlling high burden infectious diseases. A public-private partnership with the Ministry of Health, CDC, Vestergaard Frandsen and CHF International implemented a one-week integrated multi-disease prevention campaign. Method Residents of Lurambi, Western Kenya were eligible for participation. The aim was to offer services to at least 80% of those aged 15-49. 31 temporary sites in strategically dispersed locations offered: HIV counseling and testing, 60 male condoms, an insecticide-treated bednet, a household water filter for women or an individual filter for men, and for those testing positive, a 3-month supply of cotrimoxazole and referral for follow-up care and treatment.

26/08/2010  from PLoS     Read More

Intermittent preventive treatment in infants with sulphadoxine-pyrimethamine (IPTi-SP) reduces malaria morbidity by 20% to 33%. Potentially, however, this intervention may compromise the acquisition of immunity, including the tolerance towards multiple infections with Plasmodium falciparum. Plasmodium falciparum isolates were obtained from children participating in two Ghanaian IPTi-SP trials (Tamale, Afigya Sekyere) at 15 months of age, i.e., six months after they had received the second dose of IPTi-SP or placebo. By typing the polymorphic merozoite surface protein 1 (msp1) and msp2 genes, multiplicity of infection (MOI) was assessed in 389 isolates. A total of additional 133 samples were collected in Tamale at 3, 6, 9, and 12 months of age.

26/08/2010  from Malaria Journal     Read More

Whether Plasmodium falciparum, the agent of human malaria responsible for over a million deaths per year, causes fitness costs in its mosquito vectors is a burning question that has not yet been adequately resolved. Understanding the evolutionary forces responsible for the maintenance of susceptibility and refractory alleles in natural mosquito populations is critical for understanding malaria transmission dynamics. In natural mosquito populations, Plasmodium fitness costs may only be expressed in combination with other environmental stress factors hence this hypothesis was tested experimentally. Wild-caught blood-fed Anopheles gambiae s.s.

26/08/2010  from Malaria Journal     Read More

Malaria is a serious health issue in Indonesia. Mosquito control is one aspect of an integrated malaria management programme. To focus resources on priority areas, information is needed about the vectors and their habitats. This research aimed to identify the relationship between anopheline mosquitoes and topography in West Timor and Java. Information on significant malaria vectors associated with specific topography is useful for planning the mosquito control aspect of malaria management.

26/08/2010  from Malaria Journal     Read More

August 18, 2010 In a move to accelerate the development of a malaria vaccine candidate against the second most serious malaria-causing parasite, Plasmodium vivax, the PATH Malaria Vaccine Initiative (MVI) announces a collaboration with the Walter Reed Army Institute of Research (WRAIR), the US Army Medical Materiel Development Activity (USAMMDA), and GlaxoSmithKline Biologicals (GSK Bio). The partners are working to conduct a Phase 1/2a clinical trial of a vaccine approach, using the protein VMP001 developed by researchers at WRAIR, formulated with the Adjuvant System AS01 developed by GSK Bio and used in the candidate RTS,S P. falciparum vaccine, now in late-stage Phase 3 clinical testing in infants in a number of African countries. VMP001 is a modified, full-length circumsporozoite protein from the P. vivax parasite. The early-stage trial will consist of a preliminary evaluation of the safety and efficacy of this potential vaccine candidate.

25/08/2010 9:12:17 AM  by Melanie Holesgrove     Read More

Multi-drug resistant Plasmodium falciparum is a major obstacle to malaria control and is emerging as a complex phenomenon. Mechanisms of drug evasion based on the intracellular extrusion of the drug and/or modification of target proteins have been described. However, cellular mechanisms related with metabolic activity have also been seen in eukaryotic systems, e.g. cancer cells. Recent observations suggest that such mechanism may occur in P. falciparum. Methodology/Principal Findings We therefore investigated the effect of mefloquine exposure on the cell cycle of three P.

25/08/2010  from PLoS     Read More

Plasmodium falciparum apical membrane antigen-1 (AMA1) is a leading malaria vaccine candidate antigen that is expressed by sporozoite, liver and blood stage parasites. Since CD8+ T cell responses have been implicated in protection against pre-erythrocytic stage malaria, this study was designed to identify MHC class I-restricted epitopes within AMA1. A recombinant adenovirus serotype 5 vector expressing P. falciparum AMA1 was highly immunogenic when administered to healthy, malaria-naive adult volunteers as determined by IFN-gamma ELISpot responses to peptide pools containing overlapping 15-mer peptides spanning full-length AMA1. Computerized algorithms (NetMHC software) were used to predict minimal MHC-restricted 8-10-mer epitope sequences within AMA1 15-mer peptides active in ELISpot.

24/08/2010  from Malaria Journal     Read More

Odour baited resting boxes are simple, reliable and important tools for sampling malaria vector mosquitoes in surveillance and control programmes in different parts of Africa. To optimize the use of cow urine baited resting boxes for sampling An. arabiensis, a community-based study was conducted in Mabogini hamlet in the Lower Moshi irrigation scheme area. The results of these studies demonstrate an optimal method for sampling during surveillance and control programmes in rural villages of highlands and arid areas of Africa using inexpensive baits and boxes.

22/08/2010  from Parasites & Vectors     Read More

This study aimed at assessing perceptions on use of ITNs in parts of the Imo River Basin, Nigeria and its implications in preventing malaria in pregnancy. Data was collected using focus group discussions, key informant interviews and structured questionnaires. Results showed high awareness on the benefits of ITNs. Factors affecting use of ITNs included its high cost, perceptions of chemicals used to treat them as having dangerous effects on pregnancy, low utilization of antenatal care, husband's lack of interest in malaria prevention and perceptions that adolescent girls are at low risk of getting malaria. The implications of these findings include demystifying the negative perceptions on the chemicals used for net treatment and subsidizing the cost of ITNs to increase access. These findings provide important lessons for malaria programmes that aim at increasing access to ITNs by pregnant women in developing countries.

22/08/2010  from Afr J Reprod Health     Read More

Malaria is almost invariably ranked as the leading cause of morbidity and mortality in Africa. There is growing evidence of a decline in malaria transmission, morbidity and mortality over the last decades, especially so in East Africa. However, there is still doubt whether this decline is reflected in a reduction of the proportion of malaria among fevers. The objective of this systematic review was to estimate the change in the Proportion of Fevers associated with Plasmodium falciparum parasitaemia (PFPf) over the past 20 years in sub-Saharan Africa. Search strategy. In December 2009, publications from the National Library of Medicine database were searched using the combination of 16 MeSH terms.Selection criteria.

22/08/2010  from Malaria Journal     Read More

Insecticide use in public health and agriculture presents a dramatic adaptive challenge to target and non-target insect populations. The rapid development of genetically modulated resistance to insecticides is postulated to develop in two distinct ways: By selection for single major effect genes or by selection for loose confederations in which several factors, not normally associated with each other, inadvertently combine their effects to produce resistance phenotypes. Insecticide resistance is a common occurrence and has been intensively studied in the major malaria vector Anopheles gambiae, providing a useful model for examining how insecticide resistance develops and what pleiotropic effects are likely to emerge as a consequence of resistance. As malaria vector control becomes increasingly reliant on successfully managing insecticide resistance, the characterisation of resistance mechanisms and their pleiotropic effects becomes increasingly important.

20/08/2010  from Parasites & Vectors     Read More

Apicomplexan parasites release factors via specialized secretory organelles (rhoptries, micronemes) that are thought to control host cell responses. In order to explore parasite-mediated modulation of host cell signaling pathways, we exploited a phylogenomic approach to characterize the Toxoplasma gondii kinome, defining a 44 member family of coccidian-specific secreted kinases, some of which have been previously implicated in virulence. Comparative genomic analysis suggests that "ROPK" genes are under positive selection, and expression profiling demonstrates that most are differentially expressed between strains and/or during differentiation. Integrating diverse genomic-scale analyses points to ROP38 as likely to be particularly important in parasite biology. Upregulating expression of this previously uncharacterized gene in transgenic parasites dramatically suppresses transcriptional responses in the infected cell. Specifically, parasite ROP38 downregulates host genes associated with MAPK signaling and the control of apoptosis and proliferation. These results highlight the value of integrative genomic approaches in prioritizing candidates for functional validation.

20/08/2010  from Cell Host & Microbe     Read More

Individual human subjects are differentially attractive to mosquitoes and other biting insects. Previous investigations have demonstrated that this can be attributed partly to enhanced production of natural repellent chemicals by those individuals that attract few mosquitoes in the laboratory. The most important compounds in this respect include three aldehydes, octanal, nonanal and decanal, and two ketones, 6-methyl-5-hepten-2-one and geranylacetone [(E)-6,10-dimethylundeca-5,9-dien-2-one]. In olfactometer trials, these compounds interfered with attraction of mosquitoes to a host and consequently show promise as novel mosquito repellents.

20/08/2010  from Malaria Journal     Read More