Maine CDC Health Advisory

July 24, 2019

Human Powassan Case

The purpose of this health advisory is to alert clinicians to the potential for human Powassan encephalitis disease activity in Maine and to consider testing for Powassan in patients presenting with unexplained encephalitis, meningitis or high fever (100.4F or 38C) during the summer and early fall.

Maine CDC was notified of a human case of Powassan encephalitis (POW) in a Maine resident who resides in southern Maine. The individual was symptomatic in late June and hospitalized. CDC Fort Collins confirmed the Powassan result in this individual.

Powassan virus is transmitted to humans through the bite of an infected Ixodes tick. Signs and symptoms can include fever, headache, vomiting, weakness, confusion, seizures, and memory loss. Long-term neurologic problems may occur. Symptoms can begin anytime from one week to one month after the tick bite. There is no specific treatment, but people with severe Powassan virus illness often need to be hospitalized.

Advisory (PDF)