Publication: A review of mixed malaria species infections in anopheline mosquitoes
Accepted Date
2011-08-31
Issued Date
2011-08-31
Copyright Date
2011
Resource Type
Language
eng
ISSN
1475-2875 (electronic)
Rights
Mahidol University
Rights Holder(s)
BioMed Central
Bibliographic Citation
Imwong M, Nakeesathit S, Day NP, White NJ. A review of mixed malaria species infections in anopheline mosquitoes. Malar J. 2011 Aug 31;10:253.
Suggested Citation
Mallika Imwong, มัลลิกา อิ่มวงศ์, Supatchara Nakeesathit, Day, Nicholas P.J., White, Nicholas J. A review of mixed malaria species infections in anopheline mosquitoes. Imwong M, Nakeesathit S, Day NP, White NJ. A review of mixed malaria species infections in anopheline mosquitoes. Malar J. 2011 Aug 31;10:253.. Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/718
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Title
A review of mixed malaria species infections in anopheline mosquitoes
Corresponding Author(s)
Abstract
BACKGROUND: In 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.
METHODS: The 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.
RESULTS: In 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.
CONCLUSIONS: There 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.