GSG6-P1 salivary biomarker discriminates micro-geographical heterogeneity of human exposure to Anopheles bites in low and seasonal malaria areas

Background: over the past decade,a sharp decline of malaria burden has been observed in several countries. consequently,the conventional entomological methods have become insufficiently sensitive and probably under-estimate micro-geographical heterogeneity of exposure and subsequent risk of malaria transmission. in this study,we investigated whether the human antibody (ab) response to anopheles salivary gsg6-p1 peptide,known as a biomarker of anopheles exposure,could be a sensitive and reliable tool for discriminating human exposure to anopheles bites in area of low and seasonal malaria transmission. methods. a multi-disciplinary survey was performed in northern senegal where an. gambiae s.l. is the main malaria vector. human igg ab response to gsg6-p1 salivary peptide was compared according to the season and villages in children from five villages in the middle senegal river valley,known as a low malaria transmission area. results: igg levels to gsg6-p1 varied considerably according to the villages,discriminating the heterogeneity of anopheles exposure between villages. significant increase of igg levels to gsg6-p1 was observed during the peak of exposure to anopheles bites,and decreased immediately after the end of the exposure season. in addition,differences in the season-dependent specific igg levels between villages were observed after the implementation of long-lasting insecticidal nets by the national malaria control program in this area. conclusion: the gsg6-p1 salivary peptide seems to be a reliable tool to discriminate the micro-geographical heterogeneity of human exposure to anopheles bites in areas of very low and seasonal malaria transmission. a biomarker such as this could also be used to monitor and evaluate the possible heterogeneous effectiveness of operational vector control programs in low-exposure areas. © 2013 sagna et al.; licensee biomed central ltd.