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. After infection, the virus invades the central nervous system, including the spinal cord and brain. LaCrosse encephalitis is usually a mild illness, with fever, headache, nausea, vomiting, and tiredness.