title: An affordable, quality-assured community-based system for high-resolution entomological surveillance of vector mosquitoes that reflects human malaria infection risk patterns.
abstract: BACKGROUND
  More sensitive and scalable entomological surveillance tools are required to monitor low levels of transmission that are increasingly common across the tropics, particularly where vector control has been successful. A large-scale larviciding programme in urban Dar es Salaam, Tanzania is supported by a community-based (CB) system for trapping adult mosquito densities to monitor programme performance.
  
  
  METHODS
  An intensive and extensive CB system for routine, longitudinal, programmatic surveillance of malaria vectors and other mosquitoes using the Ifakara Tent Trap (ITT-C) was developed in Urban Dar es Salaam, Tanzania, and validated by comparison with quality assurance (QA) surveys using either ITT-C or human landing catches (HLC), as well as a cross-sectional survey of malaria parasite prevalence in the same housing compounds.
  
  
  RESULTS
  Community-based ITT-C had much lower sensitivity per person-night of sampling than HLC (Relative Rate (RR) [95% Confidence Interval (CI)] = 0.079 [0.051, 0.121], P < 0.001 for Anopheles gambiae s.l. and 0.153 [0.137, 0.171], P < 0.001 for Culicines) but only moderately differed from QA surveys with the same trap (0.536 [0.406,0.617], P = 0.001 and 0.747 [0.677,0.824], P < 0.001, for An. gambiae or Culex respectively). Despite the poor sensitivity of the ITT per night of sampling, when CB-ITT was compared with QA-HLC, it proved at least comparably sensitive in absolute terms (171 versus 169 primary vectors caught) and cost-effective (153US$ versus 187US$ per An. gambiae caught) because it allowed more spatially extensive and temporally intensive sampling (4284 versus 335 trap nights distributed over 615 versus 240 locations with a mean number of samples per year of 143 versus 141). Despite the very low vectors densities (Annual estimate of about 170 An gambiae s.l bites per person per year), CB-ITT was the only entomological predictor of parasite infection risk (Odds Ratio [95% CI] = 4.43[3.027,7. 454] per An. gambiae or Anopheles funestus caught per night, P =0.0373).
  
  
  CONCLUSIONS
  CB trapping approaches could be improved with more sensitive traps, but already offer a practical, safe and affordable system for routine programmatic mosquito surveillance and clusters could be distributed across entire countries by adapting the sample submission and quality assurance procedures accordingly.
authors.affiliation: Ifakara Health Institute, Coordination Office, Kiko Avenue, Mikocheni, PO Box 78373, Dar es Salaam, United Republic of Tanzania. pchaki@ihi.or.tz
authors.forename: Prosper P
authors.initials: PP
authors.lastname: Chaki
authors.forename: Yeromin
authors.initials: Y
authors.lastname: Mlacha
authors.forename: Daniel
authors.initials: D
authors.lastname: Msellemu
authors.forename: Athuman
authors.initials: A
authors.lastname: Muhili
authors.forename: Alpha D
authors.initials: AD
authors.lastname: Malishee
authors.forename: Zacharia J
authors.initials: ZJ
authors.lastname: Mtema
authors.forename: Samson S
authors.initials: SS
authors.lastname: Kiware
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhou
authors.forename: Neil F
authors.initials: NF
authors.lastname: Lobo
authors.forename: Tanya L
authors.initials: TL
authors.lastname: Russell
authors.forename: Stefan
authors.initials: S
authors.lastname: Dongus
authors.forename: Nicodem J
authors.initials: NJ
authors.lastname: Govella
authors.forename: Gerry F
authors.initials: GF
authors.lastname: Killeen
mesh_terms: D000818:Animals; D003256:Community Participation / Q000379:methods*; D009033:Culicidae / Q000145:classification / Q000254:growth & development*; D004199:Disease Vectors; D004772:Entomology / Q000379:methods*; D006801:Humans; D009032:Mosquito Control / Q000379:methods; D062486:Public Health Surveillance / Q000379:methods; D012680:Sensitivity and Specificity; D013636:Tanzania; D014329:Tropical Climate