title: Human IgG response to a salivary peptide, gSG6-P1, as a new immuno-epidemiological tool for evaluating low-level exposure to Anopheles bites.
abstract: BACKGROUND
  Human populations exposed to low malaria transmission present particular severe risks of malaria morbidity and mortality. In addition, in a context of low-level exposure to Anopheles vector, conventional entomological methods used for sampling Anopheles populations are insufficiently sensitive and probably under-estimate the real risk of malaria transmission. The evaluation of antibody (Ab) responses to arthropod salivary proteins constitutes a novel tool for estimating exposure level to insect bites. In the case of malaria, a recent study has shown that human IgG responses to the gSG6-P1 peptide represented a specific biomarker of exposure to Anopheles gambiae bites. The objective of this study was to investigate if this biomarker can be used to estimate low-level exposure of individuals to Anopheles vector.
  
  
  METHODS
  The IgG Ab level to gSG6-P1 was evaluated at the peak and at the end of the An. gambiae exposure season in children living in Senegalese villages, where the Anopheles density was estimated to be very low by classical entomological trapping but where malaria transmission occurred during the studied season.
  
  
  RESULTS
  Specific IgG responses to gSG6-P1 were observed in children exposed to very low-level of Anopheles bites. In addition, a significant increase in the specific IgG Ab level was observed during the Anopheles exposure season whereas classical entomological data have reported very few or no Anopheles during the studied period. Furthermore, this biomarker may also be applicable to evaluate the heterogeneity of individual exposure.
  
  
  CONCLUSIONS
  The results strengthen the hypothesis that the evaluation of IgG responses to gSG6-P1 during the season of exposure could reflect the real human contact with anthropophilic Anopheles and suggest that this biomarker of low exposure could be used at the individual level. This promising immuno-epidemiological marker could represent a useful tool to assess the risk to very low exposure to malaria vectors as observed in seasonal, urban, altitude or travellers contexts. In addition, this biomarker could be used for the surveillance survey after applying anti-vector strategy.
authors.affiliation: UR016-IRD-Institut de Recherche pour le Développement, Caractérisation et Contrôle des Populations de Vecteurs, 911 avenue Agropolis, BP 64501, 34394 Montpellier Cedex 5, France. anne.poinsignon@ird.fr
authors.forename: Anne
authors.initials: A
authors.lastname: Poinsignon
authors.forename: Sylvie
authors.initials: S
authors.lastname: Cornelie
authors.forename: Fatou
authors.initials: F
authors.lastname: Ba
authors.forename: Denis
authors.initials: D
authors.lastname: Boulanger
authors.forename: Cheikh
authors.initials: C
authors.lastname: Sow
authors.forename: Marie
authors.initials: M
authors.lastname: Rossignol
authors.forename: Cheikh
authors.initials: C
authors.lastname: Sokhna
authors.forename: Badara
authors.initials: B
authors.lastname: Cisse
authors.forename: François
authors.initials: F
authors.lastname: Simondon
authors.forename: Franck
authors.initials: F
authors.lastname: Remoue
mesh_terms: D000818:Animals; D000852:Anopheles / Q000276:immunology*; D015415:Biomarkers / Q000097:blood; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D007223:Infant; D007299:Insect Bites and Stings / Q000175:diagnosis* / Q000276:immunology*; D019476:Insect Proteins / Q000276:immunology*; D008297:Male; D012471:Salivary Proteins and Peptides / Q000276:immunology*; D012675:Senegal
chemical_list: D015415:Biomarkers; D007074:Immunoglobulin G; D019476:Insect Proteins; D012471:Salivary Proteins and Peptides
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