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, was first identified in 1958 near Powassan, Ontario, following the unexplained death of a young boy, Lincoln Byers.
• The virus is transmitted primarily through bites from infected woodchuck or deer ticks and has seen a significant increase in U.S. cases, with 76 diagnoses reported in 2025 compared to an average of 7-8 annually.
• Powassan virus is particularly dangerous due to its rapid transmission, occurring within 15 minutes of a tick bite, much faster than Lyme disease, which requires 36-48 hours of tick attachment.
• Symptoms range from fever and headache 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 issues.
• There are currently no specific treatments or vaccines for Powassan virus, and care is supportive; children, older adults, and immunocompromised individuals are at the highest risk of severe illness.