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

West Nile Virus Maps and Statistics

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  • 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 farm land 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 2016, 83 WNV disease cases were reported, the highest number since 2007. Fourteen (17%) had neuroinvasive presentations including encephalitis or meningitis, and there were 5 deaths. The other 69 (83%) cases had West Nile fever. Seventy-three percent (61) of the cases were male, and the median age was 55 years (range, 8 to 90 years). In 2016, 46 (55%) WNV cases were hospitalized. The majority of cases (93%) reported symptom onset in July, August, or September. Fifteen asymptomatic WNV-positive blood donors were also identified during 2016.

Charts and Graphs

Annual Summaries

Archive of Maps

National Statistics

Updated Thursday, 11-Jan-2018 13:01:45 CST