A Comparison of Adult Mosquito Trapping Methods to Assess Potential West Nile Virus Mosquito Vectors in Greece during the Onset of the 2018 Transmission Season

West Nile virus (WNV) threatens the health of humans and equines worldwide.Culex(Cx.)pipienscomplex mosquitoes are major vectors but numerous other species have been implicated. Due to variations in blood-feeding behaviour,Cx. pipiensbiotypes and hybrids influence transmission, from enzootic cycles (between mosquitoes and birds), to spill-over transmission to humans and equines. In this study, mosquitoes were collected in May-June 2018 during the early period of the transmission season from two regional units of Greece, where WNV cases had been reported in the previous four years (Palaio Faliro and Argolida). A total of 1062 mosquitoes were collected with Biogents Sentinel 2 traps collecting both a greater number of all mosquito species and theCx. pipienscomplex than CDC miniature light traps or Heavy Duty EVS traps. Molecular identification confirmed additional species includingAedes albopictus.The proportion ofCx. pipiensbiotypes in Palaio Faliro was 54.5%pipiens, 20.0%molestusand 25.5% hybrids. In Argolida, the collection comprised 68.1%pipiensbiotype, 8.3%molestusbiotype and 23.6% hybrids. Screening resulted in WNV detection in three females of thepipiensbiotype and in one hybrid. As hybrids play a role in spill-over transmission, these findings highlight the importance of entomological surveillance programs incorporating molecular xenomonitoring as an early warning before human cases at the onset of the transmission season.