title: IgG responses to the gSG6-P1 salivary peptide for evaluating human exposure to Anopheles bites in urban areas of Dakar region, Sénégal.
abstract: BACKGROUND
  Urban malaria can be a serious public health problem in Africa. Human-landing catches of mosquitoes, a standard entomological method to assess human exposure to malaria vector bites, can lack sensitivity in areas where exposure is low. A simple and highly sensitive tool could be a complementary indicator for evaluating malaria exposure in such epidemiological contexts. The human antibody response to the specific Anopheles gSG6-P1 salivary peptide have been described as an adequate tool biomarker for a reliable assessment of human exposure level to Anopheles bites. The aim of this study was to use this biomarker to evaluate the human exposure to Anopheles mosquito bites in urban settings of Dakar (Senegal), one of the largest cities in West Africa, where Anopheles biting rates and malaria transmission are supposed to be low.
  
  
  METHODS
  One cross-sectional study concerning 1,010 (505 households) children (n = 505) and adults (n = 505) living in 16 districts of downtown Dakar and its suburbs was performed from October to December 2008. The IgG responses to gSG6-P1 peptide have been assessed and compared to entomological data obtained in or near the same district.
  
  
  RESULTS
  Considerable individual variations in anti-gSG6-P1 IgG levels were observed between and within districts. In spite of this individual heterogeneity, the median level of specific IgG and the percentage of immune responders differed significantly between districts. A positive and significant association was observed between the exposure levels to Anopheles gambiae bites, estimated by classical entomological methods, and the median IgG levels or the percentage of immune responders measuring the contact between human populations and Anopheles mosquitoes. Interestingly, immunological parameters seemed to better discriminate the exposure level to Anopheles bites between different exposure groups of districts.
  
  
  CONCLUSIONS
  Specific human IgG responses to gSG6-P1 peptide biomarker represent, at the population and individual levels, a credible new alternative tool to assess accurately the heterogeneity of exposure level to Anopheles bites and malaria risk in low urban transmission areas. The development of such biomarker tool would be particularly relevant for mapping and monitoring malaria risk and for measuring the efficiency of vector control strategies in these specific settings.
authors.affiliation: Unité Mixte de Recherche MIVEGEC (IRD 224-CNRS 5290-UM1), Institut de Recherche pour le Développement, 34394, Montpellier Cedex 8, France. papa-makhtar.drame@ird.fr
authors.forename: Papa M
authors.initials: PM
authors.lastname: Drame
authors.forename: Vanessa
authors.initials: V
authors.lastname: Machault
authors.forename: Abdoulaye
authors.initials: A
authors.lastname: Diallo
authors.forename: Sylvie
authors.initials: S
authors.lastname: Cornélie
authors.forename: Anne
authors.initials: A
authors.lastname: Poinsignon
authors.forename: Richard
authors.initials: R
authors.lastname: Lalou
authors.forename: Mbacké
authors.initials: M
authors.lastname: Sembène
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Dos Santos
authors.forename: Christophe
authors.initials: C
authors.lastname: Rogier
authors.forename: Frédéric
authors.initials: F
authors.lastname: Pagès
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Le Hesran
authors.forename: Franck
authors.initials: F
authors.lastname: Remoué
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000818:Animals; D000852:Anopheles / Q000276:immunology*; D000917:Antibody Formation; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D007299:Insect Bites and Stings / Q000276:immunology*; D007303:Insect Vectors / Q000276:immunology; D008297:Male; D012471:Salivary Proteins and Peptides / Q000276:immunology*; D012675:Senegal; D014505:Urban Population; D055815:Young Adult
chemical_list: D007074:Immunoglobulin G; D012471:Salivary Proteins and Peptides