Illinois Confirms First Case of Rare Tick-Borne Powassan Virus

Key Takeaways

• Illinois has confirmed its first Powassan virus case in a resident who became seriously ill

• The virus, spread by ticks, can cause brain swelling or meningitis in severe cases

• There is no specific treatment. Prevention and tick checks remain the best defense, experts say.

WEDNESDAY, Sept. 24, 2025 (HealthDay News) — Illinois health officials are warning residents to be on alert after the state’s first case of Powassan virus was confirmed in a resident who became seriously ill.

The Illinois Department of Public Health (IDPH) hasn't determined whether the person was infected in Illinois, but officials are now testing ticks statewide for the virus.

“With warm weather still prevalent, tick-borne diseases remain a potential threat here in Illinois,” Dr. Sameer Vohra, IDPH director, told NBC Chicago.

“It’s important for everyone to guard against tick bites and the serious illnesses they can cause," Vohra added. "We urge everyone to ‘Fight the Bite’ by reducing opportunities for exposures and repelling tick bites by wearing preventive clothing. If you have been in a wooded or grassy area where ticks are common and you begin to show symptoms like fever, fatigue or headache, see a health care provider immediately.”

Other symptoms may include vomiting and weakness. 

Powassan virus is rare but can be spread to humans through bites from infected ticks, most often the blacklegged deer tick. 

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In severe cases, the virus may cause brain inflammation or meningitis, leading to confusion, trouble speaking, loss of coordination or seizures.

There is no specific treatment for Powassan virus, health officials said. The best protection is prevention, which includes checking for ticks after being outdoors, wearing long sleeves and pants, and drying clothes on high heat for 10 minutes to kill ticks.

More information

The U.S. Centers for Disease Control and Prevention has more on preventing tick bites.

SOURCE: NBC Chicago, Sept. 23, 2025

What This Means For You

If you spend time outdoors, protect yourself by wearing long sleeves, tucking pants legs into socks, using tick repellent and checking for ticks after going indoors.