Powassan Virus: Wisconsin Data

Powassan virus is a rare illness in Wisconsin spread by the blacklegged (deer) tick. The number of cases reported each year has recently increased.

The first case of Powassan virus in Wisconsin was identified in 2003. In 2024, Wisconsin had 12 reported cases of Powassan virus. There have been 67 probable and confirmed cases of Powassan virus in Wisconsin from 2003 through 2024.

Cases of Powassan virus are more common in the northern half of Wisconsin, where the blacklegged (deer) tick is found in higher numbers.

Powassan virus is preventable. Learn more about Tick Bite Prevention.

The map and graphs on this page show statewide data for Powassan virus.

For national data, visit the CDC (Centers for Disease Control and Prevention) webpage on Powassan Virus Statistics and Maps.