DHS confirms 2023’s first human case of West Nile virus

Metro Wire Staff

The Wisconsin Department of Health Services (DHS) has verified the first human case of West Nile virus in 2023.

The patient is a resident of Dane Co., the DHS said.

“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,” said State Health Officer Paula Tran. “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.”

Cases of West Nile virus have also been reported in three horses in Wisconsin, and several mosquito pools. The horse cases were located in Dunn and Clark counties, and the positive mosquitoes were from Milwaukee and Lafayette counties, the DHS said.

West Nile virus is an illness spread by the bite of an infected mosquito. About 80 percent of infected people never develop symptoms, while about 20 percent of people may experience mild illness similar to the flu. The virus can result in extreme muscle weakness, encephalitis, paralysis, coma, and death.

Since West Nile virus was first detected in Wisconsin in 200, infections in humans have been reported from June through October since 2002. An average of 17 cases of West Nile virus are reported among Wisconsin residents each year, with the risk of virus infection continuing until the first hard frost annually.