title: Serological markers of sand fly exposure to evaluate insecticidal nets against visceral leishmaniasis in India and Nepal: a cluster-randomized trial.
abstract: BACKGROUND
  Visceral leishmaniasis is the world' second largest vector-borne parasitic killer and a neglected tropical disease, prevalent in poor communities. Long-lasting insecticidal nets (LNs) are a low cost proven vector intervention method for malaria control; however, their effectiveness against visceral leishmaniasis (VL) is unknown. This study quantified the effect of LNs on exposure to the sand fly vector of VL in India and Nepal during a two year community intervention trial.
  
  
  METHODS
  As part of a paired-cluster randomized controlled clinical trial in VL-endemic regions of India and Nepal we tested the effect of LNs on sand fly biting by measuring the antibody response of subjects to the saliva of Leishmania donovani vector Phlebotomus argentipes and the sympatric (non-vector) Phlebotomus papatasi. Fifteen to 20 individuals above 15 years of age from 26 VL endemic clusters were asked to provide a blood sample at baseline, 12 and 24 months post-intervention.
  
  
  RESULTS
  A total of 305 individuals were included in the study, 68 participants provided two blood samples and 237 gave three samples. A random effect linear regression model showed that cluster-wide distribution of LNs reduced exposure to P. argentipes by 12% at 12 months (effect 0.88; 95% CI 0.83-0.94) and 9% at 24 months (effect 0.91; 95% CI 0.80-1.02) in the intervention group compared to control adjusting for baseline values and pair. Similar results were obtained for P. papatasi.
  
  
  CONCLUSIONS
  This trial provides evidence that LNs have a limited effect on sand fly exposure in VL endemic communities in India and Nepal and supports the use of sand fly saliva antibodies as a marker to evaluate vector control interventions.
authors.affiliation: Banaras Hindu University, Varanasi, India.
authors.forename: Kamlesh
authors.initials: K
authors.lastname: Gidwani
authors.forename: Albert
authors.initials: A
authors.lastname: Picado
authors.forename: Suman
authors.initials: S
authors.lastname: Rijal
authors.forename: Shri Prakash
authors.initials: SP
authors.lastname: Singh
authors.forename: Lalita
authors.initials: L
authors.lastname: Roy
authors.forename: Vera
authors.initials: V
authors.lastname: Volfova
authors.forename: Elisabeth Wreford
authors.initials: EW
authors.lastname: Andersen
authors.forename: Surendra
authors.initials: S
authors.lastname: Uranw
authors.forename: Bart
authors.initials: B
authors.lastname: Ostyn
authors.forename: Medhavi
authors.initials: M
authors.lastname: Sudarshan
authors.forename: Jaya
authors.initials: J
authors.lastname: Chakravarty
authors.forename: Petr
authors.initials: P
authors.lastname: Volf
authors.forename: Shyam
authors.initials: S
authors.lastname: Sundar
authors.forename: Marleen
authors.initials: M
authors.lastname: Boelaert
authors.forename: Matthew Edward
authors.initials: ME
authors.lastname: Rogers
mesh_terms: D000328:Adult; D000818:Animals; D000906:Antibodies / Q000097:blood* / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007194:India; D007300:Insect Control / Q000379:methods / Q000592:standards; D007303:Insect Vectors / Q000276:immunology*; D057148:Insecticide-Treated Bednets / Q000706:statistics & numerical data*; D007898:Leishmaniasis, Visceral / Q000517:prevention & control*; D016014:Linear Models; D008297:Male; D009390:Nepal; D011576:Psychodidae / Q000276:immunology*; D012463:Saliva / Q000276:immunology; D018709:Statistics, Nonparametric
chemical_list: D000906:Antibodies; D015415:Biomarkers