West Nile Virus (WNV)
West Nile virus (WNV) is a mosquitoborne 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.
WNV was found in Minnesota in 2002 and will remain a public health concern in the foreseeable future. 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. Since 2002, MDH has used dead bird reporting and virus testing to confirm West Nile Virus is widely established throughout Minnesota. As further reporting and testing would not add to this understanding, we have discontinued dead bird reporting efforts. Thank you for your help during the initial years of WNV surveillance in Minnesota.