Powassan virus was first identified as a human pathogen in 1958 when it was isolated from the brain of a young boy who died of encephalitis in the town of Powassan, Ontario (McLean and Donahue 1959).

Powassan encephalitis disease

Powassan virus cause a fatal neuroinvasive disease in humans. Fifty (50%) percent of survivors display long-term neurological sequelae. 


In North America, Powassan virus is transmitted through the bites  of Deer tick  (Ixodes scapularis), and Groundhog tick, (Ixodes cookei).  Human cases of Powassan virus infections have been documented in the United States, Canada, and Russia.  Cases in the United States are typically reported in the Northeastern and Midwestern states.  The incidence of Powassan virus human infection appears to be rising. From 2003 to present day, 144 human cases of Powassan encephalitis have been documented in the United States alone (see CDC Disease map)

Treatment and Prevention

No vaccine or specific therapy is available to prevent or treat Powassan virus infections.  Minimizing exposure to ticks is the best preventative measure for Powassan virus infection. 

Additional Information

@  CDC

Powassan virus research in Thangamani Lab

1. Development of small animal models for Powassan virus vaccine and therapeutic efficacy testing.  

2. Tick determinants of Powassan virus transmission.

3. Tick-virus-host interactions during Powassan virus transmission.

4. Effect of co-infection of Borrelia on Powassan virus transmission.