La Crosse Encephalitis

La Crosse encephalitis is an illness spread by the bite of an infected mosquito. Mosquitoes that spread La Crosse encephalitis can be found throughout 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. La Crosse encephalitis is preventable.

General information on La Crosse encephalitis, including information on signs and symptoms, treatment, and resources.

Maps and graphs with La Crosse encephalitis virus data.


Information for local health departments, health care providers, or those looking for information on reporting, surveillance, or diagnosis of La Crosse encephalitis.

Tips on preventing mosquito bites.

Questions about illnesses spread by mosquitoes? Contact us!
Phone: 608-267-9003 | Fax: 608-261-4976

Last Revised: June 15, 2022