West Nile Virus (WNV)
West Nile virus (WNV) is a mosquito-transmitted virus that can cause encephalitis (inflammation of the brain) in some people. This virus usually circulates between mosquitoes and birds in Africa and Europe. However, in 1999, an outbreak of West Nile encephalitis was reported in New York City. Since then, the virus has spread to 48 states and the District of Columbia.
In July 2002, WNV was found in Minnesota. Fortunately, most people who
are bitten by infected mosquitoes will experience either no symptoms,
or mild illness.
- About West
Nile Virus
West Nile information. Including transmission, prevention,
signs and symptoms, and answers to frequently asked questions.
- West
Nile Maps and Statistics
West Nile statistics and maps of counties with positive birds, horses and humans.
- West Nile
Information for Health Care Providers
Important information for Health Care Professionals about West Nile.
MDH is no longer taking dead bird reports. Thank you for your help during the past four years.


