Powassan (POW) Virus Information for Health Professionals
Powassan (POW) virus is a tickborne flavivirus, that includes a strain (lineage II or “deer tick virus”) that is transmitted by Ixodes scapularis. The virus can cause encephalitis or meningitis, and long-term sequelae occur in approximately 50% of patients. Approximately 10-15% of cases are fatal.
April 10, 2015: Minnesota Laboratory System (MLS) Update
May 20, 2014: Tickborne Disease Health Alert
- Medical providers should consider POW virus infection in patients with encephalitis or meningitis of probable unknown etiology that occurs during the tickborne disease transmission season (May to October).
- Signs and symptoms of POW encephalitis or meningitis may include:
- loss of coordination
- speech difficulties
- memory loss
- Long-term sequelae are common, and the case-fatality rate in reported cases is approximately 10%.
- There is no specific treatment available for POW virus infection.
- Care for patients is typically supportive and may include intravenous fluids and respiratory support.
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 testing and diagnosis of Powassan and other tickborne diseases. Call 651-201-5414 for a clinical consultation.