Cases of Rare but Dangerous Powassan Tick Virus Rising in US

A rare tick-borne illness is reaching historic levels in the United States, with cases surging as warmer weather extends the active season for the insects that carry it. The Powassan virus, known for its ability to attack the central nervous system and cause permanent brain damage, saw a record high of 76 diagnoses in 2025, according to data from the U.S. Centers for Disease Control and Prevention (CDC) reported by New York Post and Yahoo News.

This spike represents a dramatic increase from the historical average of seven to eight cases per year. As of June 16, the CDC had counted seven cases this year — five in Massachusetts and one each in New York and Wisconsin. However, Infectious Disease Advisor reports that Maine and Rhode Island each reported an additional case in the past week.

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The virus is primarily transmitted through the bite of infected deer ticks (blacklegged ticks) or woodchuck ticks. While it is less common than Lyme disease, health experts warn that Powassan is uniquely dangerous due to its transmission speed. Dr. Jorge P. Parada, a medical advisor at the National Pest Management Association in Chicago, told Fox News that Powassan can be transmitted in as little as 15 minutes after a tick bites. By contrast, Lyme disease typically requires an attachment time of 36 to 48 hours to pass bacteria to a human, though Dr. Catherine Valentine of NYU Grossman School of Medicine noted it can occur in 16 to 24 hours.

Neurological Impact and Lack of Treatment

The illness often begins with a silent incubation period of one to four weeks. While some infected people remain asymptomatic, others develop flu-like aches, fever, headache, vomiting, and weakness. In severe instances, the virus invades the central nervous system, causing meningitis or encephalitis (brain inflammation).

These neurological complications can manifest as slurred speech, confusion, seizures, loss of coordination, and paralysis. Because these symptoms develop over several days, they are sometimes mistaken for strokes, according to Infectious Disease Advisor.

The human cost of the virus is high. Dr. Parada stated that 10% to 15% of severe cases are fatal. For those who survive, about half suffer permanent neurological damage, including memory lapses, chronic headaches, and a decline in muscle strength. The severity of the disease is illustrated by the case of John Reagan, a New Hampshire resident who was recently diagnosed. According to Fox Weather, Reagan is currently bedridden, unable to speak clearly, and requires a feeding tube and ventilator to breathe.

Currently, there is no vaccine or specific medication to treat the Powassan virus. Medical care is limited to supportive therapy, which may include:

• Intravenous (IV) fluids for hydration.
• Respiratory support and ventilators for breathing.
• Feeding tubes for patients unable to swallow.
• Steroids to reduce brain swelling.

Environmental Drivers and Prevention

Experts attribute the rise in cases to climate change. Warmer temperatures have pushed the tick season further into March and November, and milder winters may be increasing the populations of rodents and deer that ticks feed on. The virus is most prevalent from late spring through mid-fall, particularly in the Northeast, the Great Lakes region, and Canada.

The virus was first identified through a tragedy in 1958 involving a 4-year-old boy named Lincoln Byers on a farm in Canada. His death was initially unexplained until researchers later found a tick harboring the virus on a dead squirrel near Powassan, Ontario, which gave the disease its name.

Public health officials emphasize that prevention is the only effective defense, especially for high-risk groups including children, older adults, and immunocompromised individuals. Recommended precautions include:

• Clothing: Wearing light-colored long sleeves and tucking pants into socks. Using clothing treated with permethrin.
• Repellents: Applying EPA-registered skin repellents, specifically those containing at least 20% DEET.
• Home Care: Tossing outdoor clothing in a hot dryer for 10 minutes to kill ticks.
• Landscaping: Keeping grass short and creating a "tick moat" of gravel or wood chips around property edges to discourage tick migration.
• Post-Exposure: Using tweezers to pull a tick off by the head and monitoring for fever for 30 days.

Summary of Risk: Powassan vs. Lyme Disease

Feature	Powassan Virus	Lyme Disease
Transmission Time	As little as 15 minutes	Typically 36 to 48 hours
Treatment	No specific cure; supportive care	Bacterial treatment available
Severity	High risk of encephalitis/death	Rarely fatal
Incubation	1 to 4 weeks	Varies

As tick activity increases across the U.S., health officials continue to monitor the spread of the virus and related tick-borne issues, such as Alpha-gal syndrome, a meat allergy linked to tick saliva that affects approximately 450,000 Americans.