Armigeres subalbatus colonization of damaged pit latrines: a nuisance and potential health risk to residents of resettlement villages in Laos.
During the resettlement of 6500 persons living around the Nam Theun 2 hydroelectric project in Laos, more than 1200 pour-flush latrines were constructed. To assess the role of these latrines as productive larval habitats for mosquitoes, entomological investigations using Centers for Disease Control (CDC) light traps, visual inspection and emergence trapping were carried out in over 300 latrines during the rainy seasons of 2008-2010. Armigeres subalbatus (Diptera: Culicidae) were nine times more likely to be found in latrines (mean catch: 3.09) than in adjacent bedrooms (mean catch: 0.37) [odds ratio (OR) 9.08, 95% confidence interval (CI) 6.74-15.11] and mosquitoes were active in and around 59% of latrines at dusk. Armigeres subalbatus was strongly associated with latrines with damaged or improperly sealed septic tank covers (OR 5.44, 95% CI 2.02-14.67; P < 0.001). Armigeres subalbatus is a nuisance biter and a putative vector of Japanese encephalitis and dengue viruses. Dengue virus serotype 3 was identified from a single pool of non-blood-fed female A. subalbatus using reverse transcription polymerase chain reaction. Maintaining a good seal around septic tanks by covering them with a layer of soil is a simple intervention to block mosquito exit/entry and contribute to vector control in resettlement villages. The scale-up of this simple, cheap intervention would have global impact in preventing the colonization of septic tanks by nuisance biting and disease-transmitting mosquitoes.
Laboratory of Vector-Borne Diseases, Institut Pasteur du Laos, Vientiane, Laos.|Department of Disease Control, London School of Hygiene and Tropical Medicine, London, U.K.|Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, the Netherlands.
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Hiscox
Laboratory of Vector-Borne Diseases, Institut Pasteur du Laos, Vientiane, Laos.
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Hirooka
Laboratory of Vector-Borne Diseases, Institut Pasteur du Laos, Vientiane, Laos.
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Vongphayloth
Department of Disease Control, London School of Hygiene and Tropical Medicine, London, U.K.
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Hill
School of Biological and Biomedical Sciences, Durham University, Durham, U.K.
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Lindsay
Laboratory of Arbovirology and Emerging Viruses, Institut Pasteur du Laos, Vientiane, Laos.
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Grandadam
Laboratory of Vector-Borne Diseases, Institut Pasteur du Laos, Vientiane, Laos.
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Brey
D063147:Animal Distribution; D000818:Animals; D002940:Circadian Rhythm; D009033:Culicidae / Q000502:physiology*; D005260:Female; D006801:Humans; D007812:Laos; D008297:Male; D011157:Population Dynamics; D012621:Seasons; D014038:Toilet Facilities
Armigeres; Laos; flavivirus; latrine; nuisance biting