Wisconsin records 1st human case of West Nile virus in 2023

Health officials in Wisconsin have confirmed the state’s first human case of West Nile virus this year.

The Wisconsin Department of Health Services (DHS) announced Friday that a Dane County resident contracted the virus.

The state had previously only confirmed three cases in horses, along with several mosquito pools in 2023. Minnesota has also confirmed cases in horses this year but not yet any human cases.

In light of the case, DHS is reminding residents that the risk of West Nile infection continues until the first hard frost.

“This confirmed case in a Wisconsin resident is a reminder that even as summer winds down, we still need to take precautions to prevent mosquito bites. While West Nile virus and other viruses spread by mosquitoes pose a risk to all Wisconsinites, people who have weakened immune systems are at the greatest risk for serious illness,” Wisconsin’s State Health Officer Paula Tran said.

West Nile virus was first detected in Wisconsin in 2002. Since then, DHS says the state has averaged 17 cases among Wisconsin residents per year. While most people infected simply have minor illnesses, it can be more serious for those with weakened immune systems.