Risks of Powassan virus disease
Learn about the risks of Powassan virus disease and who is most at risk.
On this page
- The risk of getting Powassan virus disease
- Who is most at risk
- Location in Canada where you are at risk
- The risks of complications
- Travel restrictions
The risk of getting Powassan virus disease
The risk of Powassan virus disease in Canada is very low. There have only been 21 cases reported as of 2017.
In most parts of Canada, the risk of getting a tick bite starts when the weather warms up in the spring and lasts through the fall. The risk of a tick bite in British Columbia is year round.
Ticks are most often found in:
- leaf piles
- tall grass
- wooded areas
Because tick populations are spreading, it is possible to be bitten outside of these areas.
The groundhog and squirrel ticks are found mostly in the burrows and nests of:
- tree squirrels
- other burrow-living mammals
Contact with these ticks is rare. However, disturbing burrows by activities such as construction or garden landscaping projects could increase the risk of exposure to these ticks.
Who is most at risk
Canadians who live, work, or play outdoors in areas in close proximity to ticks that spread the disease are at greater risk of infection. The risk of acquiring Powassan virus is much lower than the risk of acquiring Lyme disease. You should take precautions against tick bites when engaging in the following activities:
- walking your dog
- other outdoor recreational sports (e.g. golfing)
Locations in Canada where you are at risk
Squirrel ticks, which rarely bite humans, are most often found in:
- Atlantic provinces
Groundhog ticks, which also rarely bite humans, are most often found in:
- Atlantic provinces
Blacklegged ticks, which also pose a risk for Lyme disease, are most often found in:
- southern Quebec
- southern Manitoba
- parts of Nova Scotia
- parts of southern British Columbia
- southern, eastern and northwestern Ontario
- southern New Brunswick and Grand Manan Island
Ticks don't move far by themselves but they can attach to birds or other migratory animals, and may fall off far from their original location. For this reason, it's possible to find infected ticks in other areas than the ones listed above.
There are ongoing surveillance activities in Canada to monitor and confirm areas where infected ticks may be found.
The risks of complications
Long-term neurologic problems may occur, and can include recurrent headaches, issues with memory, and muscle wasting.
Approximately 10 percent of serious cases that develop encephalitis (inflammation of the brain) caused by Powassan virus disease are fatal.
If you travel to the United States, please be aware that Powassan virus disease is a risk. Cases of Powassan virus disease have been reported primarily from:
- northeastern states
- the Great Lakes region
The U.S. Centers for Disease Control and Prevention (CDC) website has more information on the risks of Powassan virus in the United States.
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