title: Spatio-temporal analysis of malaria vector density from baseline through intervention in a high transmission setting.
abstract: An increase in effective malaria control since 2000 has contributed to a decline in global malaria morbidity and mortality. Knowing when and how existing interventions could be combined to maximise their impact on malaria vectors can provide valuable information for national malaria control programs in different malaria endemic settings. Here, we assess the effect of indoor residual spraying on malaria vector densities in a high malaria endemic setting in eastern Uganda as part of a cohort study where the use of long-lasting insecticidal nets (LLINs) was high.
  
  
  
  Anopheles mosquitoes were sampled monthly using CDC light traps in 107 households selected randomly. Information on the use of malaria interventions in households was also gathered and recorded via a questionnaire. A Bayesian spatio-temporal model was then used to estimate mosquito densities adjusting for climatic and ecological variables and interventions.
  
  
  
  Anopheles gambiae (sensu lato) were most abundant (89.1%; n = 119,008) compared to An. funestus (sensu lato) (10.1%, n = 13,529). Modelling results suggest that the addition of indoor residual spraying (bendiocarb) in an area with high coverage of permethrin-impregnated LLINs (99%) was associated with a major decrease in mosquito vector densities. The impact on An. funestus (s.l.) (Rate Ratio 0.1508; 97.5% CI: 0.0144-0.8495) was twice as great as for An. gambiae (s.l.) (RR 0.5941; 97.5% CI: 0.1432-0.8577).
  
  
  
  High coverage of active ingredients on walls depressed vector populations in intense malaria transmission settings. Sustained use of combined interventions would have a long-term impact on mosquito densities, limiting infectious biting.
authors.affiliation: WorldPop, Geography and Environment, University of Southampton, Southampton, UK. V.A.Alegana@soton.ac.uk.|Flowminder Foundation, Stockholm, Sweden. V.A.Alegana@soton.ac.uk.
authors.forename: Victor A
authors.initials: VA
authors.lastname: Alegana
authors.affiliation: Infectious Diseases Research Collaboration, Kampala, Uganda.|London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Simon P
authors.initials: SP
authors.lastname: Kigozi
authors.affiliation: Infectious Diseases Research Collaboration, Kampala, Uganda.|Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda.
authors.forename: Joaniter
authors.initials: J
authors.lastname: Nankabirwa
authors.affiliation: Infectious Diseases Research Collaboration, Kampala, Uganda.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Arinaitwe
authors.affiliation: Infectious Diseases Research Collaboration, Kampala, Uganda.
authors.forename: Ruth
authors.initials: R
authors.lastname: Kigozi
authors.affiliation: Infectious Diseases Research Collaboration, Kampala, Uganda.
authors.forename: Henry
authors.initials: H
authors.lastname: Mawejje
authors.affiliation: Infectious Diseases Research Collaboration, Kampala, Uganda.
authors.forename: Maxwell
authors.initials: M
authors.lastname: Kilama
authors.affiliation: WorldPop, Geography and Environment, University of Southampton, Southampton, UK.|Flowminder Foundation, Stockholm, Sweden.
authors.forename: Nick W
authors.initials: NW
authors.lastname: Ruktanonchai
authors.affiliation: WorldPop, Geography and Environment, University of Southampton, Southampton, UK.|Flowminder Foundation, Stockholm, Sweden.
authors.forename: Corrine W
authors.initials: CW
authors.lastname: Ruktanonchai
authors.affiliation: London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Drakeley
authors.affiliation: School of Biological and Biomedical Sciences, Durham University, Durham, UK.
authors.forename: Steve W
authors.initials: SW
authors.lastname: Lindsay
authors.affiliation: Department of Medicine, San Francisco General Hospital, University of California, San Francisco, USA.
authors.forename: Bryan
authors.initials: B
authors.lastname: Greenhouse
authors.affiliation: Infectious Diseases Research Collaboration, Kampala, Uganda.|Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda.
authors.forename: Moses R
authors.initials: MR
authors.lastname: Kamya
authors.affiliation: Institute for Health Metrics and Evaluation, University of Washington, Seattle, USA.
authors.forename: David L
authors.initials: DL
authors.lastname: Smith
authors.affiliation: WorldPop, Geography and Environment, University of Southampton, Southampton, UK.|Faculty of Science and Technology, Lancaster University, Lancaster, UK.|School of Geography, Archaeology and Palaeoecology, Queen's University Belfast, Belfast, BT7 1NN, Northern Ireland, UK.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Atkinson
authors.affiliation: Department of Medicine, San Francisco General Hospital, University of California, San Francisco, USA.
authors.forename: Grant
authors.initials: G
authors.lastname: Dorsey
authors.affiliation: WorldPop, Geography and Environment, University of Southampton, Southampton, UK.|Flowminder Foundation, Stockholm, Sweden.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Tatem
mesh_terms: D000818:Animals; D000852:Anopheles / Q000145:classification / Q000254:growth & development*; D015331:Cohort Studies; D008288:Malaria / Q000517:prevention & control*; D009032:Mosquito Control / Q000379:methods*; D000072138:Mosquito Vectors / Q000254:growth & development*; D011156:Population Density; D062211:Spatio-Temporal Analysis; D014454:Uganda
keywords: Anopheles; Anopheles gambiae; Indoor Residual Spraying; Malaria; Modelling