A review of mixed malaria species infections in anopheline mosquitoes

Malaria Journal

Review

Mallika Imwong¹  Supatchara Nakeesathit²  Nicholas J White³  Nicholas PJ Day³ 

[1] Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;Center for Emerging and Neglected Infectious Diseases, Mahidol University, Bangkok, Thailand;Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;Centre for Tropical Medicine, Churchill Hospital, Oxford, UK;

关键词: Malaria;    Mixed Infection;    Falciparum Malaria;    Vivax Malaria;    Vivax Infection;   

DOI  :  10.1186/1475-2875-10-253

 received in 2011-04-21, accepted in 2011-08-31,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundIn patients with malaria mixed species infections are common and under reported. In PCR studies conducted in Asia mixed infection rates often exceed 20%. In South-East Asia, approximately one third of patients treated for falciparum malaria experience a subsequent Plasmodium vivax infection with a time interval suggesting relapse. It is uncertain whether the two infections are acquired simultaneously or separately. To determine whether mixed species infections in humans are derived from mainly from simultaneous or separate mosquito inoculations the literature on malaria species infection in wild captured anopheline mosquitoes was reviewed.MethodsThe biomedical literature was searched for studies of malaria infection and species identification in trapped wild mosquitoes and artificially infected mosquitoes. The study location and year, collection methods, mosquito species, number of specimens, parasite stage examined (oocysts or sporozoites), and the methods of parasite detection and speciation were tabulated. The entomological results in South East Asia were compared with mixed infection rates documented in patients in clinical studies.ResultsIn total 63 studies were identified. Individual anopheline mosquitoes were examined for different malaria species in 28 of these. There were 14 studies from Africa; four with species evaluations in individual captured mosquitoes (SEICM). One study, from Ghana, identified a single mixed infection. No mixed infections were identified in Central and South America (seven studies, two SEICM). 42 studies were conducted in Asia and Oceania (11 from Thailand; 27 SEICM). The proportion of anophelines infected with Plasmodium falciparum parasites only was 0.51% (95% CI: 0.44 to 0.57%), for P. vivax only was 0.26% (95% CI: 0.21 to 0.30%), and for mixed P. falciparum and P. vivax infections was 0.036% (95% CI: 0.016 to 0.056%). The proportion of mixed infections in mosquitoes was significantly higher than expected by chance (P < 0.001), but was one fifth of that sufficient to explain the high rates of clinical mixed infections by simultaneous inoculation.ConclusionsThere are relatively few data on mixed infection rates in mosquitoes from Africa. Mixed species malaria infections may be acquired by simultaneous inoculation of sporozoites from multiply infected anopheline mosquitoes but this is relatively unusual. In South East Asia, where P. vivax infection follows P. falciparum malaria in one third of cases, the available entomological information suggests that the majority of these mixed species malaria infections are acquired from separate inoculations.

【 授权许可】

Unknown   
© Imwong et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.