Powassan Virus (POW)

Reviewed: July 2023

Powassan (POW) virus disease is rare, but often serious disease caused by a virus that is spread by the bite of infected ticks. The virus is not transmitted directly from person-to-person. The virus is named after Powassan, Ontario where it was first discovered in 1958. It can cause symptoms ranging from mild flu-like symptoms to life threatening encephalitis (inflammation of the brain). In New York State, there are generally 1 to 9 cases of POW virus disease reported each year. Nationally, approximately 239 cases of POW virus disease were reported over the past 10 years (the most up-to-date national statistics can be found at https://www.cdc.gov/powassan/statistics.html). Prevention by following proper precautions to reduce exposure to ticks is the best defense against POW virus disease.

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