Heterogeneous human exposure to arbovirus vectors in an African urban context using immuno-epidemiological biomarker of Aedes aegypti bites

Uncontrolled urbanization led to a specific environment, promoting the spread of Aedes mosquitoes in many African cities. The objective of the study was to assess human exposure to Aedes mosquito bites in the urban area of Abidjan, Cote dIvoire, by using antibody-based biomarkers. A cross-sectional study was undertaken during the short rainy season in 3 different neighborhoods (Bromakote, Anoumabo, and Petit-Bassam) presenting various socio-environmental and entomological characteristics. The specific IgG responses to Aedes Nterm-34kDa salivary peptide, previously validated as a relevant individual biomarker of exposure to mosquito bites, were assessed in children and analyzed according to neighborhoods and age classes. The specific IgG level was significantly different according to the 3 neighborhoods and higher in Bromakote compared to Anoumabo and Petit-Bassam. No significant difference in specific IgG level was observed according to age. We also noticed an association between the level of specific IgG responses and Ae. aegypti densities or various socio-environmental factors. This study indicated that Human exposure to Aedes vector appeared to be dependent on neighborhoods within the same city, which could be related to some socio-environmental factors. Antibody-based biomarkers of human exposure to Aedes bites could be a helpful tool for assessing the heterogeneity of urban exposure to arbovirus vectors in the framework of monitoring the risk of arbovirus infections, and for evaluating the effectiveness of vector control strategies in national control programs.