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.
- Long-term sequelae occur in approximately half of those patients affected with encephalitis or meningitis and approximately 10-15% of cases are fatal.
- 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.
- Illness onsets follow a similar pattern as other tickborne diseases with most cases becoming sick in May, June, and July.
- In 2017, seven cases of Powassan virus disease were reported in Minnesota.
- Six (86%) of seven cases were male.
- Median age of cases was 61 years (range, 9 to 74 years).
- All seven cases presented with severe illness affecting the central nervous system (meningitis or encephalitis).
Charts and Graphs
- Reported Cases of Powassan virus disease in Minnesota
by Year, 2008-2017 (PDF)
Graph showing the number of reported cases of Powassan virus disease in Minnesota by year.
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.
- High Risk Areas for Tickborne Diseases in Minnesota
A map that shows counties of highest tickborne disease risk in Minnesota.
Annual Summary Statistics
- Arboviral Disease, 2016
Minnesota Department of Health Disease Control Newsletter Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2016
- Arboviral Disease, 2015
- Arboviral Disease, 2014
- Arboviral Disease, 2013
- Arboviral Disease, 2012
- Arboviral Disease, 2011
- Arboviral Disease, 2010
- Powassan Virus Statistics & Maps
Maps, charts, tables, and reports from the CDC.