If you are enjoying the great outdoors, be aware that local blacklegged ticks may transmit diseases such as Lyme disease, Anaplasmosis, Babesiosis, and Powassan virus. Blacklegged ticks are hard ticks and commonly found in wooded areas or areas with tall grasses. On July 1, 2023, Ontario Ministry of Health and Long-Term Care made Anaplasmosis, Babesiosis, and Powassan Virus reportable as Diseases of Public Health Significance. Since 2020, the health unit is no longer accepting ticks taken off human hosts for identification and testing.
Preventing tick bites
You can prevent tick bites, and help prevent the spread of tick-borne diseases by:
- Applying an approved insect repellent containing DEET or Icaridin and/or wearing permethrin-treated clothing.
- Doing a tick check on yourself, your children, and pets after playing outdoors.
- Promptly removing any ticks you find.
- Removing tick habitats around your property.
- Consider contacting your primary health care provider/pharmacist – see our Bitten by a Tick? resource for more information.
Ticks are very small and hard to see. When found, it should be removed immediately using fine-tipped tweezers to grasp the tick as close to your skin as possible without crushing it. Once you have removed a tick, wash your skin with soap and water and then disinfect your skin and your hands with rubbing alcohol or an iodine swab. You can also submit a photo of the tick to etick.ca for identification.
Lyme disease
Lyme Disease is caused by a type of bacteria found in blacklegged ticks that can be transmitted to humans through a bite. Symptoms of Lyme disease include:
- a bull’s eye rash (this occurs in approximately 70-80% of cases)
- fatigue
- muscle or joint pain
- headache
- fever/chills
- stiff neck
- decreased appetite
Public Health Ontario has posted a map of Estimated Risk Areas for Lyme Disease in Ontario. These areas are calculated as a 20 km radius from the centre of a location where blacklegged ticks were found through drag sampling. Estimated risk areas are locations where blacklegged ticks have been identified or are known to occur and where people have the potential to encounter infective ticks.
Incubation period
Can be three to 30 days, though most commonly seven to 10 days.
Anaplasmosis
Anaplasmosis is caused by a type of bacteria that is transmitted to humans through the bite of an infected blacklegged tick. This tick can also cause Lyme disease. Effective July 1, 2023, anaplasmosis became a reportable disease of public health significance in Ontario.
For most people, anaplasmosis is mild. Symptoms usually resolve within 30 days, even without treatment. However, more severe illness can occur in certain people. These include older individuals, and those who have a weakened immune system. A delay in diagnosis and treatment may also result in more severe illness.
The first symptoms usually appear within one to two weeks following the bite of an infected tick. Symptoms of anaplasmosis can include:
- Fever, chills
- Severe headache
- Muscle aches
- Cough
- Confusion
- Nausea, vomiting, diarrhea
- Loss of appetite
See your health care provider if you become ill after being bitten by a tick, or if you have been where ticks live. Your health care provider can order blood tests to look for evidence of anaplasmosis. They may prescribe antibiotics while you wait for test results, if anaplasmosis or another infection caused by ticks is suspected.
Incubation period
One to two weeks.
Babesiosis
Babesiosis is a parasitic infection transmitted through the bite of an infected blacklegged tick. Most human cases occur because of exposure to areas known to have infected blacklegged ticks. The majority of infections are asymptomatic. However, infected individuals may develop mild to severe systemic symptoms.
Signs and symptoms
- Fever, chills, sweats
- Headache
- Body aches
- Loss of appetite
- Nausea or fatigue
- Hemolytic anemia
- Fatigue
- Jaundice
- Dark urine and renal failure
Incubation Period
One to four weeks following tick bite; One to nine weeks after contaminated blood transfusion (up to 24 weeks).
Powassan virus
Powassan virus disease is a rare infection transmitted through the bite of an infected blacklegged tick, or less commonly the groundhog tick or squirrel tick. Most people who become infected are asymptomatic; however, infected individuals may show mild to severe symptoms such as fever, headache, nausea, vomiting, weakness or muscle and joint pain. Approximately 1 out of 10 people with severe disease die. Severe disease may result in meningitis and/or encephalitis with symptoms that may include confusion, loss of coordination, difficulty speaking, paralysis, seizures, or coma. There are no medications to prevent or treat Powassan virus infection. Antibiotics do not treat viruses. The virus is not transmitted from person to person, except in rare instances by blood transfusion. Because the virus can be transmitted through blood, persons who were recently diagnosed with Powassan virus infection should not donate blood and bone marrow for 120 days following infection.
Incubation period
One week to one month.
Resources related to ticks and tick-borne illnesses
- Bitten by a Tick? – HPEPH
- Permethrin-treated clothing – PHAC
- Lyme Disease Overview – Government of Canada
- Anaplasmosis Overview – Public Health Ontario
- Babesiosis Overview – Public Health Ontario
- Powassan Overview – Public Health Ontario
- Tick-borne Diseases – CDC
Last updated May 7, 2024
