Tick-borne Disease Health Alert
June 29, 2011
Time-sensitive: Tick-borne Disease
Minnesota Records First Death from Tick-Borne Powassan Virus
MDH urges medical providers to note the following:
The Minnesota Department of Health (MDH) will issue a press release today reporting the first known death in Minnesota from Powassan (POW) virus, a tick-borne flavivirus that can cause encephalitis or meningitis. A second case of encephalitis likely due to POW virus was also reported to date in 2011. The press release will emphasize the use of repellents containing DEET or permethrin to prevent tick bites.
MDH urges medical providers to note the following (also available at Tick-Transmitted Disease Information for Health Professionals).
- Powassan (POW) virus, a tick-borne flavivirus related to West Nile virus, can cause encephalitis or meningitis. Six POW cases were identified in Minnesota residents from 2008-2010. In 2011, two cases of encephalitis likely due to POW virus have been identified to date. One case, a woman in her 60s from northern Minnesota, died from the infection. The other case, a man in his 60s from Anoka County, is recovering at home.
- One strain of POW virus is transmitted by blacklegged ticks (also known as deer ticks) (Ixodes scapularis), which also carry Lyme disease, anaplasmosis, and babesiosis.
- POW cases in Minnesota from 2008-2011 were exposed to ticks in a wide area of northern Minnesota. MDH has also identified POW-positive ticks across northern Minnesota and in southeastern Minnesota.
- Medical providers should consider the possibility of POW virus infection in patients with central nervous system disease who have recent histories of activities in wooded areas (with or without known tick bites) during Minnesota’s warm weather months.
- The only laboratories that offer testing for POW virus are at state health departments (including MDH) and CDC. At this time, no commercial laboratories offer serologic testing for the virus.
- Serum or CSF specimens from patients with central nervous system disease can be submitted directly to the MDH Public Health Laboratory for arboviral disease testing, including POW virus.
- In the event of a Minnesota state government shutdown starting July 1, please contact MDH at 651-201-5414 to speak with an on-call epidemiologist about timely testing for POW virus on a case-by-case basis. Specimens sent directly to the MDH Public Health Laboratory without prior consultation with an MDH epidemiologist will likely not be tested until the shutdown is over.
- Viral encephalitis and arboviral diseases are reportable to MDH; reports need to include demographic, clinical, and laboratory information. Please contact MDH tick-borne disease epidemiology staff at 651-201-5414 for associated forms.