- Many people who become infected with Powassan (POW) virus do not develop any symptoms.
- The incubation period (time from tick bite to onset of illness) ranges from about 1 week to 1 month.
- POW virus can infect the central nervous system and cause encephalitis (inflammation of the brain) and meningitis (inflammation of the membranes that surround the brain and spinal cord).
- Symptoms can include fever, headache, vomiting, weakness, confusion, loss of coordination, speech difficulties, and seizures.
- Approximately half of survivors have permanent neurological symptoms, such as recurrent headaches, muscle wasting and memory problems.
- Approximately 10% of POW virus encephalitis cases are fatal.
- There are no vaccines or medications to treat or prevent POW virus infection.
- If you think you or a family member may have POW virus disease, see your health care provider for evaluation and diagnosis.
- Persons with severe POW illnesses often need to be hospitalized. Treatment may include respiratory support, intravenous fluids, and medications to reduce swelling in the brain.
- Page last reviewed: February 9, 2015
- Page last updated: February 9, 2015
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