Mosquito Surveillance

Diseases Spread by Mosquitoes

There are many illnesses spread by mosquitoes in Wisconsin. Not all mosquitoes spread illnesses, and you won't get sick from every mosquito bite, but it is important to make sure you are aware of mosquitoes, the illnesses they can spread, and how to prevent bites in the first place.

Illnesses spread by mosquitoes in Wisconsin: Eastern Equine Encephalitis (EEE), Jamestown Canyon virus, La Crosse encephalitis, Saint Louis encephalitis, West Nile Virus (WNV). Check out this fact sheet for more information.


West Nile Virus (WNV) 

West Nile virus is an illness spread by the bite of an infected mosquito. The type of mosquitoes that spread West Nile virus can be found in every county in Wisconsin. Not all mosquito bites will make you sick, but it is still important to take steps to protect yourself and your family while enjoying time outdoors. West Nile virus is preventable.

WNV Data on Wisconsin DHS website

The first cases of West Nile virus (WNV) in humans in Wisconsin were reported in 2002.

In 2022, Wisconsin had six confirmed and probable cases of West Nile virus.