title: Risk factors for mosquito house entry in the Lao PDR.
abstract: BACKGROUND
  Construction of the Nam Theun 2 hydroelectric project and flooding of a 450 km(2) area of mountain plateau in south-central Lao PDR resulted in the resettlement of 6,300 people to newly built homes. We examined whether new houses would have altered risk of house entry by mosquitoes compared with traditional homes built from poorer construction materials.
  
  
  RESULTS
  Surveys were carried out in the Nam Theun 2 resettlement area and a nearby traditional rice farming area in 2010. Mosquitoes were sampled in bedrooms using CDC light traps in 96 resettlement houses and 96 traditional houses and potential risk factors for mosquito house entry were recorded. Risk of mosquito house entry was more than twice as high in traditional bamboo houses compared with those newly constructed from wood (Putative Japanese Encephalitis (JE) vector incidence rate ratio (IRR) = 2.26, 95% CI 1.38-3.70, P = 0.001; Anopheline IRR = 2.35, 95% CI: 1.30-4.23, P = 0.005). Anophelines were more common in homes with cattle compared against those without (IRR = 2.32, 95% CI: 1.29-4.17, P = 0.005).Wood smoke from cooking fires located under the house or indoors was found to be protective against house entry by both groups of mosquito, compared with cooking in a separate room beside the house (Putative JE vector IRR = 0.43, 95% CI: 0.26-0.73, P = 0.002; Anopheline IRR = 0.22, 95% CI: 0.10-0.51, P<0.001).
  
  
  CONCLUSIONS
  Construction of modern wooden homes should help reduce human-mosquito contact in the Lao PDR. Reduced mosquito contact rates could lead to reduced transmission of diseases such as JE and malaria. Cattle ownership was associated with increased anopheline house entry, so zooprophylaxis for malaria control is not recommended in this area. Whilst wood smoke was protective against putative JE vector and anopheline house entry we do not recommend indoor cooking since smoke inhalation can enhance respiratory disease.
authors.affiliation: Institut Pasteur du Laos, Vientiane, Lao PDR. alexandra.hiscox@wur.nl
authors.forename: Alexandra
authors.initials: A
authors.lastname: Hiscox
authors.forename: Phasouk
authors.initials: P
authors.lastname: Khammanithong
authors.forename: Surinder
authors.initials: S
authors.lastname: Kaul
authors.forename: Pany
authors.initials: P
authors.lastname: Sananikhom
authors.forename: Ruedi
authors.initials: R
authors.lastname: Luthi
authors.forename: Nigel
authors.initials: N
authors.lastname: Hill
authors.forename: Paul T
authors.initials: PT
authors.lastname: Brey
authors.forename: Steve W
authors.initials: SW
authors.lastname: Lindsay
mesh_terms: D000818:Animals; D000852:Anopheles; D002417:Cattle; D003465:Culex; D005260:Female; D006798:Housing; D006801:Humans; D007303:Insect Vectors; D060106:Lakes; D007812:Laos; D009032:Mosquito Control; D011210:Power Plants; D012307:Risk Factors; D012424:Rural Population