Symptoms, Diagnosis, and Treatment
- Many people infected with Powassan virus do not have symptoms.
- For people with symptoms, the time from tick bite to feeling sick ranges from 1 week to 1 month.
- Initial symptoms can include fever, headache, vomiting, and weakness.
- Powassan virus can cause severe disease, including infection of the brain (encephalitis) or the membranes around the brain and spinal cord (meningitis).
- Symptoms of severe disease include confusion, loss of coordination, difficulty speaking, and seizures.
- Approximately 1 out of 10 people with severe disease die.
- Approximately half of the people who survive severe disease have long-term health problems such as recurring headaches, loss of muscle mass and strength, and memory problems.
- Healthcare providers diagnose Powassan virus infection based on:
- Signs and symptoms
- History of possible exposure to the ticks that can carry Powassan virus
- Laboratory testing of blood or spinal fluid
- More information on diagnostic testing is available here.
- There is no medication to treat Powassan virus infection.
- People with severe disease often need to be hospitalized to receive support for breathing, staying hydrated, or reducing swelling in the brain.
- If you think you or a family member might have Powassan virus disease, see your healthcare provider.
- To learn more about treatment, visit our Healthcare Provider page.
Page last reviewed: August 20, 2021