Powassan (POW) Virus Information for Health Professionals
Powassan (POW) virus is a tick-transmitted flavivirus.
Powassan virus (POWV), a tick-borne flavivirus related to West Nile virus, can cause encephalitis or meningitis. Six cases have been identified in Minnesota residents from 2008-2010. One strain of POWV is transmitted by I. scapularis ticks (which also carry Lyme disease).
June 29, 2011: Tick-borne Disease Health Alert
- Medical providers should consider POW virus infection in patients with encephalitis or meningitis of probable unknown etiology that occurs during the tick-borne disease transmission season (May to October).
- Signs and symptoms of POW encephalitis or meningitis may include fever, headache, vomiting, weakness, confusion, loss of coordination, speech difficulties, and memory loss.
- Long-term sequelae are common, and the case-fatality rate in reported cases is approximately 10%.
Minnesota Rules Governing Communicable Diseases require health care providers to report confirmed or suspected cases of Powassan to the Minnesota Department of Health (MDH) within 1 working day.
MDH staff also are available to provide clinical consultation regarding diagnosis and treatment of Powassan and other tick-borne diseases. Call 651-201-5414 for a clinical consultation.