The global distribution of clinical episodes of Plasmodium falciparum malaria.

Public Health Group, KEMRI/Wellcome Trust Research Laboratories PO Box 43640, 00100 Nairobi, Kenya.
Nature (Impact Factor: 42.35). 04/2005; 434(7030):214-7. DOI: 10.1038/nature03342
Source: PubMed

ABSTRACT Interest in mapping the global distribution of malaria is motivated by a need to define populations at risk for appropriate resource allocation and to provide a robust framework for evaluating its global economic impact. Comparison of older and more recent malaria maps shows how the disease has been geographically restricted, but it remains entrenched in poor areas of the world with climates suitable for transmission. Here we provide an empirical approach to estimating the number of clinical events caused by Plasmodium falciparum worldwide, by using a combination of epidemiological, geographical and demographic data. We estimate that there were 515 (range 300-660) million episodes of clinical P. falciparum malaria in 2002. These global estimates are up to 50% higher than those reported by the World Health Organization (WHO) and 200% higher for areas outside Africa, reflecting the WHO's reliance upon passive national reporting for these countries. Without an informed understanding of the cartography of malaria risk, the global extent of clinical disease caused by P. falciparum will continue to be underestimated.

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    ABSTRACT: Mosquito-borne diseases represent one of the most significant threats to human health worldwide, with hundreds of millions of infections resulting in extraordinary morbidity and mortality every year. Although vector control interventions are among the most effective known ways to prevent the transmission of mosquito-borne diseases, new strategies and paradigms are desperately needed to complement currently available tools. One novel approach to vector control currently being considered is a combined push-pull strategy, which uses spatial repellents and baited traps simultaneously in order to reduce human-vector interactions and to facilitate the capture and removal of vectors from the local environment. Here, a series of interdisciplinary studies was conducted to evaluate the potential for push-pull strategies to control mosquito vectors of human disease and to better define the physiological basis of spatial repellency. First, we used a field-based experimental hut methodology to evaluate a prototype push-pull intervention against two natural malaria vector populations, Anopheles albimanus and An. vestitipennis, in northern Belize, Central America. Results show that the combined strategy can decrease human-vector interactions both indoors, by reducing mosquito entry into human-occupied huts (both An. vestitipennis and An. albimanus), and outdoors, by increasing mosquito trap efficacy (An. vestitipennis only). While these results provide clear evidence that the combined strategy has potential to limit disease transmission in and around homes, the variation in effect seen on different target vectors highlights the need to characterize the underlying behavioral ecology of mosquitoes in order to drive intervention optimization in varied transmission settings. Secondly, we used an in vitro behavioral bioassay to investigate the plasticity, heritability and physiological basis of spatial repellency behaviors in the global arbovirus vector, Aedes aegypti. While results indicate that spatial repellency is a relatively plastic behavior that likely results from a combination of factors, some heritable and others non-heritable, we were able demonstrate that transfluthrin repellent insensitivity is a recessive trait linked to reduced insecticide susceptibility in selectively bred mosquito populations. This provides novel evidence that the neurotoxic irritation of mosquitoes by sub-lethal doses of airborne insecticide is one of the primary mechanisms by which some chemicals can elicit spatial repellency behaviors in Ae. aegypti, and raises some important questions about how the long term use of certain spatial repellents, namely volatile pyrethroids, might impact vector populations over time. Collectively, the work presented here provides a valuable proof-of-principle for push-pull mosquito control strategies and supports further investment into the optimization and validation of the approach for disease vector control while highlighting the need to identify new insect behavior modifying compounds with novel, non-toxic mechanisms of action.
    09/2014, Degree: Ph.D., Supervisor: John Grieco, Ph.D.
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    ABSTRACT: Current practice in treating cases of malaria is based around the concept of combination therapy, since this offers several advantages-reduced risk of treatment failure, reduced risk of developing resistance, enhanced convenience and reduced side-effects. The effect of the supplements vitamin B2 (Riboflavin) and orange fruit juice on the potency and efficacy of some selected anti-malaria drugs (Armact, Coartem, Waipa and Fansider) as a combination therapy were investigated. 80 patients (adults) infected with malaria parasites were used. The study showed that the simultaneous administration of the drugs with vitamin B2 did not alter the potency of the drugs, while orange fruit juice altered the efficacy of the drugs. Therefore, the concomitant administration of these anti-malaria drugs (combination therapies) with orange fruit juice should be avoided during the period of malaria treatment for the effectiveness of such drugs. The result of this study also showed that concomitant administration of Riboflavin with antimalarial drugs may possess potent antimalarial effects and may therefore offer a potential drug lead for development of a safe, effective and affordable antimalarial.
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    ABSTRACT: Petroleum ether, ethyl acetate and methanol stem bark extracts of Commiphora swynnertonii were evaluated for larvicidal potential against laboratory reared late third stage instar of mosquito namely, Anopheles gambiae ss Gile, Culex quinquefasciatus Say and Aedes aegypti L. The WHO methodology was adopted with minor modification using methanol extract with concentrations ranged from 25-300μg/mL and ethyl acetate and petroleum ether extracts with concentrations ranged from 5-50μg/mL. The activity was time and dose dependent where, ethyl acetate extract revealed higher larvicidal activity with LC50 ranged from 14.6395-3.9455μg/mL, 2 5 . 1 0 9 6 - 5 . 3 4 4 2 μg/mL, 27.0405-8.4829 μg/mL for Aedes aegypti, Culex quinquefasciatus, and Anopheles gambiae at 24h, 48h, and 72h of exposure respectively. Among the three species of mosquito larvae tested, Anopheles gambiae was found to be relatively resistant to extracts followed by Culex quinquefasciatus and the weakest was Aedes aegypti. These results validate use of Commiphora swynnertonii as a potential botanical larvicidal agent in controlling mosquitoes and the spread of mosquito borne diseases.
    International Journal of Science and Research (IJSR) 03/2015; volume 4(issue 3):356-361. · 3.25 Impact Factor

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