Overwintering West Nile Virus in active Culex pipiens mosquito populations in Greece

Abstract West Nile Virus (WNV) is one of the major vector-borne diseases globally, including Greece. This is the first research study in Greece, describing identification of WNV in overwintering active Culex pipiens populations, captured in adult traps, for the time period 2021–2023. WNV positive mosquito pools were recorded in three out of the 24 study areas, representing two coastal regional units in the Attica Region suggesting a clustered circulation of WNV during the winter of 2022. Our findings underline the need of extending entomological surveillance programs to include the winter period, specifically in temperate climates and historically affected areas by WNV.