Rising Cases of Rare Tick-Borne Illness Linked to Historic Case

A rare tick-borne illness that has the potential to be fatal is currently spreading in the United States. Its origins can be traced back to a case from 1958 involving a young boy living on a farm.

The disease, named Powassan virus after the town in Ontario where it was first identified, was initially mysterious. Lincoln Byers, a 4-year-old from Canada, passed away under circumstances that puzzled medical professionals. Years later, researchers finally found a tick carrying the virus on a dead squirrel, which shed light on the unfortunate incident but also anticipated challenges for public health.

Once regarded as a rare medical oddity, cases of Powassan virus have reached unprecedented levels in the U.S. According to the Centers for Disease Control and Prevention (CDC), 76 Americans were diagnosed with the virus in 2025, marking the highest annual record. Historically, the country averaged just seven to eight cases each year.

The virus spreads mainly through bites from infected ticks, specifically the woodchuck tick and deer tick. Like other tick-borne diseases, Powassan is most common from late spring to mid-fall, coinciding with peak outdoor activity.

Public health experts express concern over the quick transmission rate of this virus. Dr. Jorge P. Parada, a medical advisor at the National Pest Management Association, emphasized that Powassan can be transmitted in as little as 15 minutes after being bitten, contrasting sharply with Lyme disease, which typically requires 36 to 48 hours of attachment to transmit.

Though Powassan remains less common than Lyme disease, it poses significant clinical concerns. Dr. Marc Siegel, a senior medical analyst, noted that the virus has an incubation period of one to four weeks, after which symptoms begin to appear.

Symptoms often start with fever, headache, vomiting, and general weakness, but some patients may show no symptoms at all. The illness can progress into severe neurological complications, such as encephalitis, which is inflammation of the brain, and meningitis, inflammation of the spinal cord membranes.

In severe cases, individuals may face confusion, loss of coordination, difficulty speaking, or even seizures. Alarmingly, about 10% of severe cases can be fatal. Those who survive may experience long-term neurological problems.

Currently, there are no specific treatments or vaccines for the Powassan virus. Medical care is primarily supportive, involving hydration and respiratory assistance. Those at greatest risk include children, older adults, and individuals with weakened immune systems.