Mosquito excreta reveals circulation of West Nile virus and its underlying ecosystem

Abstract

Emerging and endemic mosquito-borne viruses can be difficult to detect and monitor because they often cause asymptomatic infections in human or vertebrate animals or cause nonspecific febrile illness with a short recovery waiting period. Cases′ detection in vertebrate hosts can be complemented by entomological surveillance, but this method is not adapted to low infection rates in mosquito populations that typically occur in low or non-endemic areas. We identified West Nile Virus circulation in Camargue, a wetland area in South of France, using a cost effective innovative xenomonitoring method based on the molecular detection of virus in excreta from trapped mosquitoes. We also succeeded at identifying the mosquito community diversity dynamic on several sampling sites, together with the vertebrate hosts on which they fed prior to be captured using amplicon-based metagenomic on mosquito excreta without processing any mosquito. Mosquito excreta-based virus surveillance can be considered as a cost-effective and non-invasive strategy that offers the additional asset to reveal the ecological network underlying arbovirus circulation.

One Health surveillance of West Nile and Usutu viruses: a repeated cross-sectional study exploring seroprevalence and endemicity in Southern France, 2016 to 2020

“…Moreover, the combination of genetic data from other studies and ours show the presence of the same lineages for both WNV and USUV in the same region in 2015, 2018 and 2020. More precisely, the cluster of WNV Lineage 1 found in mosquitoes in 2018 has also been detected in Camargue in a horse in 2015 ( Figure 2A ) and in mosquito excreta in 2020 (a different genomic region than that used in our analysis, GenBank accession OK489805.1 [ 41 ]). The same cluster had been detected in equines in the region in 2000 and 2004 ( Figure 2A ).…”