Powassan virus disease
Powassan virus disease is spread to people through the bite of an infected Black-legged (“deer”) tick (Ixodes scapularis). This is a rare, emerging infection in the United States and human cases have been identified in Connecticut. The virus can cause severe disease. There is no vaccine to prevent or medicine to treat Powassan virus infection. The best way to prevent Powassan virus disease is to prevent tick bites.About Powassan Virus Disease
Information for Clinicians
- Clinical Guidance
- National Surveillance Case Definition
- Connecticut Provider Reporting Information
- Connecticut Laboratory Reporting Information
- Powassan virus testing at the State Public Health Laboratory
- State Public Health Laboratory Contacts – for additional information
- Tick-borne Diseases of the United States – a Reference Manual for Healthcare Providers
Connecticut Powassan Surveillance
The Connecticut Department of Public Health (DPH) added Powassan virus disease to the list of state-wide reportable diseases in 2019. DPH uses the Centers for Disease Control and Prevention surveillance case definition, which was established in 2005. Surveillance activities help characterize the epidemiology, clinical spectrum, and incidence of Powassan virus disease in Connecticut and nationally.
Connecticut Annual Infectious Diseases Statistics
Updated 2/20/2026