Malaria News |
Malaria: passive case detection and healthcare providers' choices of chemotherapy 
Prompt diagnosis and treatment play a central role in the malaria control programme in sub Saharan Africa. However, in most cases the diagnoses are never confirmed either for lack of facility or disinterest of healthcare providers resulting in over-diagnosis. To determine the proportion of clinically diagnosed malaria cases who could be confirmed with microscopy and evaluate compliance of healthcare providers with the National treatment guidelines for malaria. Participants were patients referred for malaria microscopy after the attending physicians had made clinical diagnosis of malaria. Thick blood smears were made under strict asepsis, stained and thereafter examined under oil immersion objective lens. Of the 630 patients who were referred with clinical impression of malaria, only 224 or 35.6% were positive for malaria parasite. The slide positive patients were younger with a mean age of 10.6 +/- 13.0 years versus 17.2 +/- 18.5 years [P < 0.005] for the slide negative individuals. There were only few instances of non-compliance with the National treatment guidelines for malaria. In conclusion, there appears to be over-diagnosis of malaria considering that only about a third of the clinical malaria cases were confirmed by microscopy. There is need for large epidemiological studies and possible policy review.
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Cotrimoxazole, clinical uses and malaria chemotherapy
Microbial infections still account for considerable morbidity and mortality in sub-Saharan Africa. The importance of chemotherapeutic agents cannot be over-emphasized. Some antimicrobial agents provide broad spectrum of activity spanning different classes of bacterial and protozoan diseases. Cotrimoxazole, an antifolate antimicrobial was originally meant for treatment of bacterial diseases but has been shown to be an effective drug in the treatment of malaria amongst other conditions. This review attempted to explore the pharmacology of cotrimoxazole, its many clinical uses and adverse effects. Specific experiences of the author in the application of cotrimoxazole in the treatment of acute uncomplicated falciparum malaria were highlighted and suggestions on how to optimize the use of this drug were made.
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Plasmodium falciparum parasites causing cerebral malaria share variant surface antigens, but are they specific? 
Variant surface antigens (VSA) expressed on the surface of Plasmodium falciparum-infected red blood cells constitute a key for parasite sequestration and immune evasion. In distinct malaria pathologies, such as placental malaria, specific antibody response against VSA provides protection. This study investigated the antibody response specifically directed against VSA expressed by parasites isolated from individuals presenting a given type of clinical malaria.
Plasma and isolates were obtained from four groups of Beninese subjects: healthy adults, patients presenting uncomplicated malaria (UM), cerebral malaria (CM), or pregnancy-associated malaria (PAM).
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First case of detection of Plasmodium knowlesi in Spain by Real Time PCR in a traveller from Southeast Asia
Previously, Plasmodium knowlesi was not considered as a species of Plasmodium that could cause malaria in human beings, as it is parasite of long-tailed (Macaca fascicularis) and pig-tailed (Macaca nemestrina) macaques found in Southeast Asia. A case of infection by P. knowlesi is described in a Spanish traveller, who came back to Spain with daily fever after his last overseas travel, which was a six-month holiday in forested areas of Southeast Asia between 2008 and 2009. His P. knowlesi infection was detected by multiplex Real time quantitative PCR and confirmed by sequencing the amplified fragment. Using nested multiplex malaria PCR (reference method in Spain) and a rapid diagnostic test, the P. knowlesi infection was negative.
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Isolation of viable Plasmodium falciparum merozoites to define erythrocyte invasion events and advance vaccine and drug development 
During blood-stage infection by Plasmodium falciparum, merozoites invade RBCs. Currently there is limited knowledge of cellular and molecular invasion events, and no established assays are available to readily measure and quantify invasion-inhibitory antibodies or compounds for vaccine and drug studies. We report the isolation of viable merozoites that retain their invasive capacity, at high purity and yield, purified by filtration of highly synchronous populations of schizonts. We show that the half-life of merozoite invasive capacity after rupture is 5 min at 37 -°C, and 15 min at room temperature. Studying the kinetics of invasion revealed that 80% of invasion events occur within 10 min of mixing merozoites and RBCs. Invasion efficiency was maximum at low merozoite-to-RBC ratios and occurred efficiently in the absence of serum and with high concentrations of dialyzed nonimmune serum. We developed and optimized an invasion assay by using purified merozoites that enabled invasion-inhibitory activity of antibodies and compounds to be measured separately from other mechanisms of growth inhibition; the assay was more sensitive for detecting inhibitory activity than established growth-inhibition assays. Furthermore, with the use of purified merozoites it was possible to capture and fix merozoites at different stages of invasion for visualization by immunofluorescence microscopy and EM. We thereby demonstrate that processing of the major merozoite antigen merozoite surface protein-1 occurs at the time of RBC invasion. These findings have important implications for defining invasion events and molecular interactions, understanding immune interactions, and identifying and evaluating inhibitors to advance vaccine and drug development.
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Malaria on isolated Melanesian islands prior to the initiation of malaria elimination activities
The Australian Government's Pacific Malaria Initiative (PMI) programme is supporting malaria elimination activities in both Solomon Islands and Vanuatu in conjunction with the Global Fund for Aids, Tuberculosis and Malaria (GFATM). Two remote island groups - Tafea Province, Vanuatu and Temotu Province, Solomon Islands have been selected as possible malaria elimination areas. To provide information on the prevalence and distribution of the disease within these island groups malariometric surveys were conducted during the wet seasons of 2008.
For various reasons malaria rates are declining in these provinces providing a favourable situation for local malaria elimination.
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Prospective strategies to delay the evolution of anti-malarial drug resistance: weighing the uncertainty
The evolution of drug resistance in malaria parasites highlights a need to identify and evaluate strategies that could extend the useful therapeutic life of anti-malarial drugs. Such strategies are deployed to best effect before resistance has emerged, under conditions of great uncertainty.
Here, the emergence and spread of resistance was modelled using a hybrid framework to evaluate prospective strategies, estimate the time to drug failure, and weigh uncertainty. The waiting time to appearance was estimated as the product of low mutation rates, drug pressure, and parasite population sizes during treatment. Stochastic persistence and the waiting time to establishment were simulated as an evolving branching process.
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A progressive declining in the burden of malaria in north-eastern Tanzania
The planning and assessment of malaria interventions is complicated due to fluctuations in the burden of malaria over time. Recently, it has been reported that the burden of malaria in some parts of Africa has declined. However, community-based longitudinal data are sparse and the reasons for the apparent decline are not well understood.
There has been a marked decline in malaria in the study villages during the past few years. This decline is likely to be due to a combination of factors that include improved access to malaria treatment provided by the trained village helpers, protection from mosquitoes by increased availability of insecticide-impregnated bed nets and a reduced vector density.
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