Publication: Natural human Plasmodium infections in major Anopheles mosquitoes in western Thailand
Issued Date
2016
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eng
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Mahidol University
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BioMed Central
Bibliographic Citation
Parasites & Vectors . Vol.9, (2016), 17
Suggested Citation
Patchara Sriwichai, Yudthana Samung, Suchada Sumruayphol, Kirakorn Kiattibutr, Chalermpon Kumpitak, Anon Payakkapol, Jaranit Kaewkungwal, Guiyun Yan, Liwang Cui, Jetsumon Sattabongkot, Mahidol University. Faculty of Tropical Medicine. Mahidol Vivax Research Unit Natural human Plasmodium infections in major Anopheles mosquitoes in western Thailand. Parasites & Vectors . Vol.9, (2016), 17. doi:10.1186/s13071-016-1295-x Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/3128
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Title
Natural human Plasmodium infections in major Anopheles mosquitoes in western Thailand
Abstract
Background: The Thai-Myanmar border is a remaining hotspot for malaria transmission. Malaria transmission in this
region continues year-round, with a major peak season in July-August, and a minor peak in October-November.
Malaria elimination requires better knowledge of the mosquito community structure, dynamics and vectorial status
to support effective vector control.
Methods: Adult Anopheles mosquitoes were collected using CDC light traps and cow bait in 7 villages along the
Thai-Myanmar border in January 2011 - March 2013. Mosquitoes were determined to species by morphological
characters. Plasmodium-positivity was determined by circumsporozoite protein ELISA.
Results: The 2986 Anopheles mosquitoes collected were assigned to 26 species, with Anopheles minimus sensu lato
(s.l.) (40.32 %), An. maculatus s.l. (21.43 %), An. annularis s.l. (14.43 %), An. kochi (5.39 %), An. tessellatus (5.26 %), and
An. barbirostris s.l. (3.52 %) being the top six most abundant species. Plasmodium-infected mosquitoes were found
in 22 positive samples from 2906 pooled samples of abdomens and heads/thoraxes. Four mosquito species were
found infected with Plasmodium: An. minimus s.l., An. maculatus s.l., An. annularis s.l. and An. barbirostris s.l. The
infectivity rates of these mosquitoes were 0.76, 0.37, 0.72, and 1.74 %, respectively. Consistent with a change in
malaria epidemiology to the predominance of P. vivax in this area, 20 of the 22 infected mosquito samples were
P. vivax-positive. The four potential vector species all displayed apparent seasonality in relative abundance. While
An. minimus s.l. was collected through the entire year, its abundance peaked in the season immediately after the
wet season. In comparison, An. maculatus s.l. numbers showed a major peak during the wet season. The two
potential vector species, An. annularis s.l. and An. barbirostris s.l., both showed peak abundance during the transition
from wet to dry season. Moreover, An. minimus s.l. was more abundant in indoor collections, whereas An. annularis
s.l. and An. barbirostris s.l. were more abundant in outdoor collections, suggesting their potential role in outdoor
malaria transmission.
Conclusions: This survey confirmed the major vector status of An. minimus s.l. and An. maculatus s.l. and identified
An. annularis s.l. and An. barbirostris s.l. as additional vectors with potential importance in malaria transmission after
the wet season.