Lyme Disease : Frequently Asked Questions

Risk Areas

1. In what areas of Ontario am I at a higher risk of encountering blacklegged ticks and contracting Lyme disease?

While low, there is always a potential risk of contracting Lyme disease (disease agent: Borrelia burgdorferi) anywhere in Ontario; however, the risk increases where there are established or endemic populations of the tick that transmits the agent of Lyme disease (blacklegged or deer ticks, Ixodes scapularis). In Ontario, blacklegged ticks are more commonly found in areas along the north shores of Lake Erie, Lake Ontario, and the St. Lawrence River.

Locations with endemic populations of ticks are: Long Point Provincial Park, Turkey Point Provincial Park, Rondeau Provincial Park, Point Pelee National Park, Prince Edward Point National Wildlife Area, Wainfleet Bog Conservation Area, and in the St. Lawrence Islands National Park area.

2. What is the difference between an "established" and "endemic" population of blacklegged ticks?

The yearly recurrence of Lyme disease is dependent on an endemic population of ticks breeding in an area. An established population is defined as an annually recurring, reproducing tick population wherein all stages of development are present (i.e., larvae, nymphs, and adults), with no Lyme disease. An endemic population is defined as an established population that exhibits evidence of Lyme disease transmission between the blacklegged ticks and resident animal populations.

3. I live close to, but not in an area with an endemic population of blacklegged ticks; am I still at risk of contracting Lyme disease? Are the borders of established regions well defined?

The precise boundaries of these tick populations are difficult to define and will eventually expand into neighbouring areas, given suitable climate and habitat conditions.

Blacklegged ticks are known to feed on migratory birds and, as a result, can be transported throughout Ontario, originating from endemic populations within the province and the US. It is possible for people to encounter blacklegged ticks almost anywhere in the province; however, as one travels further from regions with endemic tick populations, the risk diminishes.

4. I travel throughout Ontario, Canada, and the US; what areas have endemic populations of blacklegged ticks?

In North America, the greatest risk of exposure to Lyme disease-associated ticks occurs in the North-eastern (e.g., Connecticut, Massachusetts, New Jersey, and New York) and Midwest (e.g., Minnesota and Wisconsin), US. In Canada, blacklegged ticks are known to be found in south-western Quebec, southern and eastern Ontario, south-eastern Manitoba, New Brunswick, and Nova Scotia as well as much of southern British Columbia. Note: In British Columbia the vector tick is called the western blacklegged tick or Ixodes pacificus.

Ontarians travelling to high-risk areas must take personal protection precautions when outdoors. Blacklegged ticks infected with the agent of Lyme disease are much more common in the US compared to the relatively limited areas in southern and eastern Ontario. The Ministry of Health and Long-Term Care, the Public Health Agency of Canada (PHAC), and its partners continue to research to identify new and emerging tick populations in Ontario and to assess public health risks through prevalence of the Lyme disease agent.

Diagnosing, Testing and Treatment

1. What are the current methods for testing people for Lyme disease? Are the current methods widely accepted in public health and science?

The Public Health Ontario Laboratories (PHO) conducts serological (blood) testing for the causative agent of Lyme disease - B. burgdorferi.

PHO follows a scientifically-validated two-tier testing protocol (i.e., enzyme immunoassay (EIA) and Western immunoblot assay). This process is in alignment with Canadian Public Health Laboratory Network recommendations, and uses Health Canada-approved test kits.

2. Private laboratories offer Lyme disease testing; do their tests meet scientifically-validated Canadian and American standards?

Private laboratories may not follow the same testing protocols and recommendations as the majority of Canadian or American laboratories.

Private testing facilities have been known to use testing methods which have not been fully established.

3. Are blood tests and their results the only factors used by doctors to diagnose Lyme disease?

Serology is just one of several methods physicians evaluate when diagnosing Lyme disease and should never be used as the sole defining factor in diagnosis.

Physicians interpret serology test results in conjunction with clinical signs and symptoms, along with a detailed tick-exposure history for the patient.

4. Who is responsible for conducting serology tests for Lyme disease in Ontario?

Lyme disease testing is conducted by the OAHPP PHL. The Ministry of Health and Long-Term Care and provincial health units do not perform Lyme disease tests, nor are they the governing bodies of the PHL.

If you want more information on testing or have any concerns about your test results, please contact your physician.

5. What are the recommended treatments for Lyme disease?

Physicians are responsible for treating their patients according to their signs, symptoms and laboratory results. The most common treatment of Lyme diseases is a course of antibiotics. The MOHLTC does not give specific recommendations on treatment as the responsibility lies with the treating physician.

6. Who is responsible for doctor awareness and education regarding Lyme disease and its diagnosis?

The College of Physicians and Surgeons of Ontario (CPSO)., the Ontario Medical Association (OMA), and medical schools across Ontario remain the most appropriate bodies through which physicians are provided information.

7. I am worried about Lyme disease and I sometimes find ticks on my family members and even our pets; can I get these ticks tested for Lyme disease?

People who find ticks on themselves are encouraged to submit the ticks to their local health unit; physicians and public health officials can submit human-borne ticks to the PHL for identification.

If a tick is identified as Ixodes scapularis (blacklegged or deer tick), it is sent to the National Microbiology Laboratory and tested for the agent of Lyme disease. Ticks collected from animals are not sent for identification or Lyme disease testing.

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