IgG responses to the gSG6-P1 salivary peptide for evaluating human exposure to Anopheles bites in urban areas of Dakar region, Sénégal.

Papa M Drame (1) , Vanessa Machault (2, 3, 4) , Abdoulaye Diallo (5) , Sylvie Cornélie (6) , Anne Poinsignon (7) , Richard Lalou (8) , Mbacké Sembène (9) , Stéphanie dos Santos (10) , Christophe Rogier (4, 11) , Frédéric Pagès (4) , Jean-Yves Le Hesran (5) , Franck Remoué (6)

1 MIVEGEC - Maladies infectieuses et vecteurs : écologie, génétique, évolution et contrôle
2 LAERO - Laboratoire d'aérologie
3 CNES - Centre National d'Études Spatiales [Toulouse]
4 URMITE - Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes
5 Santé de la mère et de l'enfant en milieu tropical : épidémiologie génétique et périnatale
6 MIVEGEC-VCG - Vector Control Group
7 MIVEGEC-TRIAD - Transmission-Interactions-Adaptations hôtes/vecteurs/pathogènes
8 LPED - Laboratoire Population-Environnement-Développement
9 Faculté des Sciences et Techniques (FST)
10 IRD [Sénégal] - Institut de recherche pour le développement
11 Institut Pasteur de Madagascar

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.

Domaines: Sciences du Vivant [q-bio]

Papa M Drame, Vanessa Machault, Abdoulaye Diallo, Sylvie Cornélie, Anne Poinsignon, et al.. IgG responses to the gSG6-P1 salivary peptide for evaluating human exposure to Anopheles bites in urban areas of Dakar region, Sénégal.. Malaria Journal, 2012, 11, pp.72. ⟨10.1186/1475-2875-11-72⟩. ⟨pasteur-00835699⟩