Powassan (POW) Virus Information for Health Professionals
Powassan (POW) virus is a tick-transmitted flavivirus.
On this page:
Clinical Presentation/Diagnosis
Reporting
Powassan diseasePowassan 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 |
Clinical Presentation/Diagnosis
- 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%.
Reporting
- Reporting
Powassan Virus
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.
Spotlight
Blacklegged tick (deer tick) life stages next to a metric ruler. The adult ticks (two ticks at the left) are approximately 1/8 of an inch long, while the nymph (third from left) is just under 1/16 of an inch.
June 29, 2011: Tick-borne Disease Health Alert
Minnesota Records First Death from Tick-Borne Powassan Virus
May 6, 2011: Tick-borne Disease Health Alert
Anaplasmosis Rivals Lyme Disease As Record Numbers of Minnesotans Sick from Tick-Borne Diseases in 2010.
Special Review Panel Unaimously Upholds Lyme Disease Treatment Guidelines: Short-term Antibiotics Proven to be Best Treatment for Patients
4/2010 Update: Special review panel unanimously upholds Lyme disease treatment guidelines. Infectious Diseases Society of America (IDSA)
High Risk Areas in Minnesota
A map that shows counties of highest Tick-borne risk in Minnesota.
Ticks
Learn about blacklegged ticks (deer ticks) including their life cycle, feeding habits, habitat, and population control. Also includes information on American dog ticks, the vector of Rocky Mountain spotted fever in Minnesota.
Preventing Tick-Transmitted Disease
Information about minimizing your risk of tick-transmitted diseases, protecting your pets, and removing ticks.
Tickborne Prevention Poster: Spray Before You Work or Play
If you have questions or comments about this page, use our IDEPC Comment Form or call 651-201-5414 (TTY: 651-201-5797) for the MDH Infectious Disease Epidemiology, Prevention and Control Division.
