Powassan Virus
Pathogen
Powassan virus (a flavivirus)
Carried by
Blacklegged / deer tick (Ixodes scapularis)
Powassan is a tick-borne virus that, while rare, is increasing and can cause severe neurological disease. Unlike bacterial infections that need many hours of attachment, Powassan can be transmitted in as little as 15 minutes, which makes prompt tick removal especially important.
Symptoms
- Many infections cause no symptoms
- Fever, headache, vomiting, weakness
- In severe cases: encephalitis or meningitis — confusion, seizures, difficulty speaking
- Long-term neurological problems in a significant share of severe cases
Testing
Antibody testing (IgM and neutralizing antibodies) and spinal fluid analysis, usually run through the CDC or reference labs.
Labs often used in the Lyme community:
See our Testing Guide to understand your options.
Geography
Concentrated in the Northeast and Great Lakes regions, most often late spring through mid-fall.
Explore the Where Ticks Live map to see what's carried in your region.
Treatment overview
There is no antiviral medication and no vaccine — care is supportive. About 1 in 10 severe cases is fatal, and survivors frequently have lasting effects, which is why prevention and fast tick removal matter most.
Frequently asked questions
How fast can Powassan be transmitted?
Possibly within 15 minutes of attachment — far faster than the many hours bacterial infections like Lyme typically require. This is why removing ticks immediately is so important.