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.
authors.affiliation: Department of Medical Entomology, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand. patchara.sri@mahidol.ac.th.
authors.forename: Patchara
authors.initials: P
authors.lastname: Sriwichai
authors.affiliation: Department of Medical Entomology, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand. yudthana.sam@mahidol.ac.th.
authors.forename: Yudthana
authors.initials: Y
authors.lastname: Samung
authors.affiliation: Department of Medical Entomology, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand. suchada.sum@mahidol.ac.th.
authors.forename: Suchada
authors.initials: S
authors.lastname: Sumruayphol
authors.affiliation: Department of Medical Entomology, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand. kirakorn.kia@mahidol.ac.th.|Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400. kirakorn.kia@mahidol.ac.th.
authors.forename: Kirakorn
authors.initials: K
authors.lastname: Kiattibutr
authors.affiliation: Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400. chalermpon.kum@mahidol.ac.th.
authors.forename: Chalermpon
authors.initials: C
authors.lastname: Kumpitak
authors.affiliation: Department of Medical Entomology, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand. anon.pay@mahidol.ac.th.
authors.forename: Anon
authors.initials: A
authors.lastname: Payakkapol
authors.affiliation: Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand. jaranit.kae@mahidol.ac.th.
authors.forename: Jaranit
authors.initials: J
authors.lastname: Kaewkungwal
authors.affiliation: Program in Public Health, University of California, Irvine, CA, 92697, USA. guiyuny@uci.edu.
authors.forename: Guiyun
authors.initials: G
authors.lastname: Yan
authors.affiliation: Department of Entomology, Pennsylvania State University, University Park, PA, 16802, USA. luc2@psu.edu.
authors.forename: Liwang
authors.initials: L
authors.lastname: Cui
authors.affiliation: Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400. jetsumon.pra@mahidol.ac.th.
authors.forename: Jetsumon
authors.initials: J
authors.lastname: Sattabongkot
mesh_terms: D000818:Animals; D000852:Anopheles / Q000145:classification / Q000469:parasitology*; D005843:Geography; D006801:Humans; D007303:Insect Vectors / Q000145:classification / Q000469:parasitology*; D008288:Malaria / Q000469:parasitology / Q000635:transmission*; D016780:Malaria, Vivax / Q000469:parasitology / Q000635:transmission; D002052:Myanmar / Q000453:epidemiology; D010961:Plasmodium / Q000276:immunology* / Q000302:isolation & purification; D010966:Plasmodium vivax / Q000276:immunology / Q000302:isolation & purification; D012621:Seasons; D034101:Sporozoites; D013785:Thailand / Q000453:epidemiology