West Nile Virus

Importance: West Nile virus (WNV), a neurotropic flavivirus spread by Culex species mosquitoes, is the leading cause of mosquito-borne disease in the contiguous US. From 2014 to 2023, a mean of 1300 WNV neuroinvasive disease cases and 130 deaths were reported annually in the US. Observations: Almost all WNV infection occurs via mosquito bites, but transmission can rarely occur via blood transfusion, organ transplantation, and transplacental, perinatal, breastmilk, percutaneous, and conjunctival exposure. Since 2018, large WNV outbreaks have been reported in Europe, Tunisia, Israel, and the US. In 2021, the largest county-level US outbreak occurred in Arizona, with 1487 disease cases and 101 deaths reported.…