Powassan Virus

Vector-borne and zoonotic diseases result from the transmission of viruses, bacteria, or parasites from animals or insects to humans. Anaplasmosis, Babesiosis and Powassan Virus are examples of diseases that can result from the bite of a disease carrying tick.

Ottawa Public Health’s (OPH) main objective is prevention and management of these diseases through the control of effective identification and case management in addition to public education and messaging.

On June 22, 2023, the Ministry of Health announced amendments to Ontario Regulation 135/18 (Designation of Diseases) and Ontario Regulation 569 (Reports) under the Health Protection and Promotion Act to include the addition of Anaplasmosis, Babesiosis, and Powassan virus to Ontario Regulations as designated and reportable diseases requiring notification to local public health for investigation. The effective date for these amendments was July 1, 2023.

What is Powassan virus?

Powassan virus disease is an infection transmitted through the bite of an infected blacklegged tick, and less frequently by the groundhog tick or squirrel tick.

Signs and symptoms

Most infected individuals do not show any symptoms, but some may experience mild to severe fever, headache, nausea, vomiting, weakness, or muscle and joint pain. In severe cases, the disease can lead to meningitis and/or encephalitis, with symptoms such as confusion, loss of coordination, difficulty speaking, paralysis, seizures, or coma.

Prevention

Prevention of tick bites is a cornerstone of Powassan virus prevention. Avoid tick bites by adopting the following practices:

  • Application of a Health Canada approved insect repellent containing DEET or icaridin to exposed skin and to clothing
  • Wearing long pants, a long-sleeved shirt, shoes and socks to cover exposed skin
  • Tucking pants into socks
  • Wearing light coloured clothing so it is easier to spot ticks
  • If possible, staying on the trails when hiking in the woods or walking in long grass
  • Performing a "full body" check (also on children, and pets if applicable) for ticks. Ticks often attach in areas such as between toes, behind knees, in the groin, armpits and scalp.

What if I find a tick?

If you find a tick on your body, remove the tick as soon as possible. The risk of getting a tick-borne disease increases with the length of time the tick remains attached.

Since Ottawa is considered an at-risk area for disease carrying ticks, it is important to contact your doctor or health care provider if you believe a tick has been attached to you for 24 or more hours, or if you are unsure how long the tick has been attached to you, so that your doctor or health care provider can determine if you need treatment with antibiotics. Treatment with antibiotics would be considered when:

  • the tick has been attached for 24 or more hours or is fully or partially engorged and
  • it has been less than or equal to 72 hours since the tick has been removed.

Your doctor or health care provider will advise you about what should be done straight away. Immediate actions include watching for symptoms of disease for the next 30 days after a tick bite, and, if appropriate, taking a single dose of antibiotics prophylactically.

If the tick was attached for less than 24 hours and its body does not appear swollen from feeding or if you removed a tick and more than 72 hours have passed, you should still be on the lookout for signs and symptoms of disease for the next 30 days. If you do develop symptoms, consult your doctor or health care provider.

As of January 11, 2023, your local pharmacist can treat and prescribe medications for tick exposures. Visit the Government of Ontario News Release webpage.

Removing ticks 

how to remove a tick

  • Use fine-pointed tweezers.
  • Grasp the tick's head as close to the skin as possible and pull slowly until the tick is removed.
  • Do not twist or rotate the tick. Do not use a match, lotion or anything else on the tick.
  • Wash the bite site with soap and water.
  • If you are going to see your doctor or health care provider and want to bring the tick with you, place the tick in an empty pill vial or zip-lock bag with a moistened paper towel. For help with identifying a tick, submit a picture through “eTick” (www.etick.ca), an electronic tick identification platform.
  • You can dispose of a live tick by flushing it down the toilet, or placing it in a sealed bag/container and disposing it with your household garbage.

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