Powassan Virus Disease Statistics

Since the first Minnesota case was reported in 2008, cases of Powassan virus disease have been reported every year except for 2014 and 2015. A peak of 11 cases was reported in 2011.

In 2022, eight cases of Powassan virus disease were reported in Minnesota. All but one of the cases presented with severe illness affecting the central nervous system (meningitis or encephalitis), and one case died.

• 6 (75%) of the reported cases were male
• Ages of all cases ranged from 3 to 76 years

The majority of patients report being exposed to ticks in north-central Minnesota. Based on findings from routine tick surveillance activities, the virus appears to be widely distributed throughout the wooded areas of Minnesota. Most cases experience illness onset in late spring to mid-summer, with the potential for additional cases appearing in fall, corresponding with peak blacklegged tick activity.

Charts and Graphs

• Reported Cases of Powassan virus disease in Minnesota by Year, 2008-2022 (PDF)
  Graph showing the number of reported cases of Powassan virus disease in Minnesota by year.

Maps

Most Powassan virus disease cases report likely exposure to blacklegged ticks in the same east-central, north-central, and southeast Minnesota counties where the risk of Lyme disease is greatest.

• Reported Cases of Powassan Virus Disease by County of Residence, Minnesota, 2008-2022
  A map of reported cases of Powassan virus disease by county of residence.
• High Risk Areas for Tickborne Diseases in Minnesota 
  A map that shows counties of highest tickborne disease risk in Minnesota.

Annual Summaries

• Endemic Mosquitoborne & Tickborne Arboviral Diseases: Annual Summary of Reportable Diseases
  Historical data on West Nile virus from the Minnesota Department of Health Disease Control Newsletter Annual Summary of Communicable Diseases.

National Statistics

• CDC: Powassan Virus Data & Maps
  Maps, charts, tables, and reports from the CDC.