ATLANTA, June 23 (Our Illinois Times) — A tick bite that seems brief may still be enough to spread Powassan virus, a rare infection that can inflame the brain and leave survivors with lasting neurologic problems, federal health officials and researchers say.
The Centers for Disease Control and Prevention says the virus is spread by infected ticks, most often in the Northeast and Great Lakes regions, and that reported cases have increased in recent years.
A Defense Centers for Public Health–Aberdeen fact sheet, citing studies, says some ticks can transmit the virus in as little as 15 minutes of feeding. A peer-reviewed case report said human infection can occur within hours of attachment.
The CDC says early symptoms can include fever, headache, vomiting and weakness. In severe cases, the infection can progress to encephalitis or meningitis and can cause confusion, loss of coordination, speech problems, seizures and paralysis.
The agency says Powassan virus disease has no vaccine and no medicine that treats it. For neuroinvasive disease, the CDC says about 10% of patients die and about half of survivors have long-term neurologic deficits.
CDC clinical guidance says older adults, children and people with weakened immune systems are at higher risk for neuroinvasive disease. The agency also says the virus can rarely be transmitted through blood transfusion.
Powassan is carried by ticks including blacklegged ticks, groundhog ticks and squirrel ticks. The Defense public-health page says the disease has been documented in the United States since the first case was diagnosed in New Jersey in 1970 and that CDC counted about 397 reported cases from 2004 through 2024.
