Minnesota Department Of Health (MDH) has a list of reportable diseases for questions or information please call: Acute Disease Epidemiology Section 612-676-5414
LaCrosse Encephalitis: is a viral illness that is transmitted to people through the bite of an infected mosquito.  Most people infected with this virus will have either no symptoms, or a mild flu-like illness.  A small percentage of people may develop encephalitis (inflammation of the brain).  Approximately 1 - 3% of these encephalitis cases are fatal, and another 15% of patients have long-term nervous system problems.  Most of the severe cases start with headache, fever, nausea, and lethargy.  The illness may rapidly progress into disorientation, seizures, and coma.  There is no treatment for the illness other than supportive care until the illness is over.
	What kind of mosquito transmits LaCrosse? In Minnesota we have approximately 50 species of mosquitoes.  Not all feed on people, and the primary vector of LaCrosse is the Eastern Tree Hole mosquito.  Tree Hole mosquito is found almost exclusively in wooded or shaded areas, and usually does not fly more then 200 yards from the area where it was produced.  It feeds during the day, unlike many of our pest mosquitoes that feed mostly at dusk and dawn.
How to Report a Dead Bird The best way to detect West Nile Virus in an area is to look for birds that have been bitten by infected mosquitoes, and killed by the virus.  MDH is collecting reports of dead birds from around the state, and testing some of these birds for the virus. We are especially interested in American Crow and Blue Jays.  All species of birds should be reported to MDH call Toll Free 877-676-5414.
West Nile Encephalitis is a viral disease transmitted to people and horses through the bite of an infected mosquito.  It is maintained in a transmission cycle involving one or more species of mosquitoes and birds.  Current research is focusing on which mosquitoes and birds are most important in this cycle.  West Nile is usually found in Africa and southern Europe.
The virus was first reported in North America during a 1999 outbreak of encephalitis in New York City.  Most of the severe human cases begin with a sudden onset of fever, headache, stiff neck, and vomiting.