Modeling the population dynamics of Rift Valley fever virus mosquito vectors in the western Mediterranean Basin

Abstract

Rift Valley fever (RVF) is a zoonotic vector-borne disease mainly transmitted by mosquitoes, and present in Africa, the Arabian Peninsula, and the Indian Ocean. The endemic situation in Mauritania, and the recent outbreaks in Libya have raised concerns about the potential spread of the virus in the Mediterranean Basin, where competent mosquitoes are present. Because vector abundance is one of the drivers of RVF virus (RVFV) transmission, knowledge on species distributions and population dynamics is needed to implement entomological surveillance and to assess the risk of viral circulation. Here, we adapted a modeling framework of mosquito population dynamics to five species considered as possible RVFV vectors in the western Mediterranean Basin (Aedes caspius, Aedes detritus, Aedes vexans, Culex pipiens and Culex theileri). The mechanistic model used a daily time step and a 0.1° x 0.1° spatial resolution and was based on meteorological data along with published vector distribution maps. We gathered mosquito trapping data from Spain, France, Italy and Morocco to calibrate the model and to evaluate its predictions. The temporal correlation between predicted abundance and observational data was satisfactory. Goodness-of-fit was better for Aedes species, thus offering the means to target the area of interest for the surveillance of Ae. caspius, a highly competent mosquito species.