ATLANTA, June 23 (Our Illinois Times) — A tick bite can turn serious fast when Powassan virus is involved. Federal health officials say the rare infection can be transmitted within minutes, and once it reaches the brain it can cause encephalitis, seizures, paralysis and lasting neurologic injury.
The Centers for Disease Control and Prevention says reported Powassan cases have increased in recent years, even though the disease remains uncommon. Most U.S. infections occur in the Northeast and Great Lakes regions during tick-active months from late spring through mid-fall.
Powassan virus is spread by infected ticks, including blacklegged ticks, groundhog ticks and squirrel ticks, according to the CDC and the Defense Centers for Public Health–Aberdeen. The military public-health agency says studies show transmission can occur in as little as 15 minutes of feeding.
That timing makes Powassan different from many other tick-borne diseases, which often require longer attachment periods before transmission. A peer-reviewed case report on the virus said human infection can occur within hours of attachment, and cited experimental evidence of transmission as quickly as 15 minutes.
Early illness can look like a flu-like infection, with fever, headache, vomiting and weakness, the CDC says. In more severe cases, the virus can cause inflammation of the brain or the membranes around it, leading to confusion, loss of coordination, speech problems, seizures, paresis and paralysis.
The CDC says there are no vaccines to prevent Powassan virus disease and no medicines to treat it. For people who develop neuroinvasive disease, the agency says about 10% die and about half of survivors have long-lasting neurologic deficits.
Powassan virus was first identified in 1958 in Powassan, Ontario, and the Defense Centers for Public Health–Aberdeen says the first U.S. case was diagnosed in New Jersey in 1970. The agency says CDC records show about 397 reported U.S. cases from 2004 through 2024.
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 spread through blood transfusion.
