Rare tick-borne virus turns deadly fast as US cases reach record high, experts warn

Key Points:

• Powassan virus, a rare and potentially fatal tick-borne illness first identified in 1958 near Powassan, Ontario, is now spreading across the United States, with cases reaching a record high of 76 in 2025 compared to an average of 7-8 annually.
• The virus is transmitted primarily through bites from infected woodchuck or deer ticks, with transmission occurring rapidly—within 15 minutes of a tick bite—making it more dangerous than Lyme disease, which requires a longer attachment time.
• Initial symptoms of Powassan virus include fever, headache, vomiting, and weakness, but it can progress to severe neurological complications such as encephalitis and meningitis, with about 10% of severe cases resulting in death and many survivors facing long-term neurological effects.
• There are no specific treatments or vaccines for Powassan virus; medical care focuses on supportive therapies, and those most at risk for severe illness include children, older adults, and immunocompromised individuals.
• Public health experts emphasize the growing threat posed by Powassan virus due to its rapid transmission and increasing incidence, especially during peak tick activity from late spring to mid-fall.