Detection of flaviviruses and alphaviruses in mosquitoes in Central Macedonia, Greece, 2018.

Culex mosquitoes are vectors of several flaviviruses and alphaviruses posing a potential risk to public and veterinary health. In order to gain an insight into the flaviviruses and alphaviruses circulating in the five regional units of Central Macedonia in northern Greece, 17,470 female Culex spp. mosquitoes collected during 2018 were tested for these viruses. Among 229 mosquito pools, West Nile virus (WNV) was detected in 10 (4.4%) pools, while insect-specific flavi- and alphaviruses were detected in 2 (0.9%) and 8 (3.5%) pools, respectively. WNV minimum infection rate (MIR) was 0.57. The highest MIR was identified in Thessaloniki regional unit, where several human cases of WNV infection occurred in 2018. All ten WNV sequences cluster into the Central European subclade of lineage 2. It is of note that the first WNV-positive mosquito pool was detected two weeks prior the report of the first human case in the area, suggesting that testing of mosquitoes could serve as early warning system. Image, graphical abstract [ABSTRACT FROM AUTHOR]