About Powassan Virus

Powassan virus is an illness spread by ticks. It spreads to humans by the bite of an infected deer tick, also known as a black-legged tick.

Powassan virus is rare in Wisconsin. Nationally, Powassan virus cases are most common in the northeast and Great Lakes regions.

The first case in the state was identified in 2003. Since then, most cases of Powassan virus have been in northern Wisconsin.

Anyone can get Powassan virus. People who spend more time outdoors are at a higher risk of getting bitten by an infected tick.

Ticks are commonly found in areas with woods, brush, or tall grass and are most active in Wisconsin during May through November, but they can be active anytime temperatures are above  40°F.

Protect yourself with Tick Bite Prevention

Powassan virus cases in Wisconsin during the last 10 years

Powassan 101

Contact us

Questions about illnesses spread by ticks? We’re here to help.

Bureau of Communicable Diseases
Phone: 608-267-9003
Fax: 608-261-4976

Last revised July 15, 2024