LaCrosse encephalitis is a rare disease that is spread by infected mosquitoes. It gets its name from LaCrosse, Wisconsin, where the infection was first recognized in 1963. LaCrosse encephalitis is one of a group of mosquito-borne virus diseases that can affect the central nervous system and cause severe complications and even death. Other similar diseases are eastern equine encephalitis, western equine encephalitis, and St. Louis encephalitis. LaCrosse encephalitis is caused by the LaCrosse encephalitis virus, an arbovirus.
Arbovirus is short for ar thropod- bo rne virus .
In the United States, arboviruses are spread mainly by infected mosquitoes. Most recent cases are from West Virginia. This mosquito breeds in tree holes and manmade containers and bites during the day. People are not an important part of the life cycle of the virus. In rare cases, however, people who live in or visit an area where the virus lives can be infected by the bite of an infected mosquito.