West Nile Encephalitis Maps and Statistics - Minnesota Dept. of Health

West Nile Virus Maps and Statistics

  • West Nile virus (WNV) was first found in Minnesota in 2002 and has since become the most commonly reported mosquitoborne disease in the state.
  • The highest risk areas for WNV in Minnesota include the western and central portions of the state. Open areas, such as farmland and prairie, provide the best habitat for Culex tarsalis, the primary mosquito vector of the virus.
  • Similar to other arboviruses, most WNV cases occur later in the summer (July through September) when infected vector populations are at their highest level.
  • In 2018, 63 WNV disease cases were reported in Minnesota, slightly more than the median number of cases per year (49) from 2012 to 2017.
    • 39 (62%) cases were hospitalized and 35 (56%) cases had a severe illness affecting the central nervous system (encephalitis or meningitis), including two fatalities in older adults.
    • 44 (70%) cases were male.
    • Median age was 62 years (range, 21 to 91 years).
    • 21 WNV-positive blood donors who did not have any symptoms of illness were also identified.
    • Interactive West Nile virus disease data
      Interactive facts and figures available through MN Public Health Data Access. Includes reported cases of West Nile virus disease in Minnesota by year, month, age, sex, and symptom as well as a map of West Nile virus disease cases over time.

Maps and Graphs

Annual Summaries

Archive of Maps

National Statistics

Updated Friday, 29-Apr-2022 13:02:12 CDT