ATLANTA, June 23 (Our Illinois Times) — A brief tick bite can still carry a rare but serious risk. The Centers for Disease Control and Prevention says Powassan virus, a tick-borne infection that can damage the brain, has been reported more often in recent years and can be transmitted in a very short time after a tick attaches.
CDC says the virus is spread to people by infected ticks and is most often reported in the Northeast and Great Lakes regions, especially during late spring through mid-fall when ticks are most active. Public-health officials say most cases remain rare, but the disease can be severe when it reaches the nervous system.
The agency says early symptoms can include fever, headache, vomiting and weakness. In more serious cases, Powassan virus can cause encephalitis or meningitis, leading to confusion, loss of coordination, speech problems, seizures and paralysis.
CDC clinical guidance says neuroinvasive Powassan disease is fatal in about 10% of cases, and about half of survivors have long-lasting neurologic problems. The agency says older adults, children and people with weakened immune systems are at higher risk of neuroinvasive disease.
There is no vaccine to prevent Powassan virus disease and no medicine to treat it, CDC says.
The virus is carried by several tick species, including blacklegged ticks, groundhog ticks and squirrel ticks, according to CDC and the Defense Centers for Public Health–Aberdeen. The Defense public-health office says studies show transmission can occur in as little as 15 minutes of feeding. A peer-reviewed case report and review literature also describe transmission as possible within hours of attachment.
CDC says reported cases have increased in recent years, although the disease remains uncommon. The Defense Centers for Public Health–Aberdeen says CDC counted about 397 reported cases from 2004 through 2024.
Public-health sources describe the disease as one of the most serious tick-borne infections in the United States because it can progress quickly to neurologic illness. CDC says Powassan infection can be mild or even cause no symptoms in some people, but once the nervous system is involved, the illness can leave permanent injury.
The Defense public-health office says Powassan is the only tick-borne encephalitis virus found in the United States. CDC says rare transmission through blood transfusion has also been documented.
Researchers and public-health agencies continue to track the virus as a concern in tick-endemic parts of the country, especially in states such as Wisconsin, Minnesota, Massachusetts and New York.
