Lyme disease is caused by the bacterium Borrelia burgdorferi, transmitted to humans through the bite of an infected blacklegged tick. Lyme disease is designated as a disease of public health significance and is reportable under the Ontario Health Protection and Promotion Act.
Prevention, early detection and treatment are essential to reduce the burden of Lyme disease. Health providers should be familiar with:
- The expanding risks areas
- Management of tick bites and clinical guidance
- Reporting requirements
- WDGPH’s online tick photo submission form for tick species identification and surveillance
Important information about testing:
In September 2021, The National Microbiology Laboratory stopped accepting blacklegged ticks for bacterial testing of Borrelia burgdorferi as part of the passive tick surveillance program.
Although there remain private laboratories that test ticks for Borrelia burgdorferi, laboratory testing of the specimen should not be used to diagnose Lyme disease in humans.
- Estimated Risk Areas and Trends
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The incidence of Lyme disease reported in Ontario and Canada has increased in recent years. The rise is attributable to climate change and other changes driving rapid geographic expansion of blacklegged ticks and supporting conditions suitable for B. burgdorferi. Blacklegged ticks infected with the pathogen causing Lyme disease are known to be present in Wellington-Dufferin-Guelph and neighbouring areas.
Estimate Risk Areas
According to Public Health Ontario, although estimated risk areas have been mapped, it is important to note that blacklegged ticks feed on and are transported by migratory birds and there is consequently a possibility of encountering an infective blacklegged tick almost anywhere in Ontario:
Lyme Disease Trends
- Public Health Ontario (Provincial)
- National Surveillance (National)
- Management of Tick Bites
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Tick removal
- Health Canada: How to remove a tick (written instructions)
- Health Canada: How to properly remove a tick (video)
Tick species identification
- To have the tick species identified and support local surveillance efforts, please use WDGPH’s online tick photo submission form.
- WDGPH aims to provide a response within 1-3 business days as often as possible (and often responds in under 2 business days).
- Healthcare providers should consider timelines associated with post-exposure prophylaxis (i.e. PEP can be offered within 72 hours of the tick being removed) when determining whether to wait for results from tick species identification services.
- If identifying the tick in your office, please consult TickEncounter’s:
Clinical guidance for management of tick bites
Lyme disease is caused by the bacterium Borrelia burgdorferi and is transmitted to humans through the bite of an infected blacklegged tick. According to Health Canada, the bacterium is transmitted by infected nymphs and adult females. For further information on this, visit: Health Canada: Lyme Disease for Healthcare professionals.
Clinical guidance documents:
- For physicians: Clinical Guidance Document for Physicians – Management of Tick Bites and Investigation of Early Localized Lyme Disease
- Note that assessing whether an area has a prevalence of infected ticks above or below a certain value may have limitations. According to Public Health Ontario’s report (page 2), “Despite these estimated risk areas, it is important to note that… there is a possibility of encountering an infective blacklegged tick almost anywhere in Ontario.”
- For pharmacists: Assessment and Prescribing Algorithm for Pharmacists: Antibiotic Prophylaxis to Prevent Lyme Disease following a Tick Bite
Additional clinical resources
- Early Lyme Disease Management in Primary Care (Centre for Effective Practice)
- Lyme Disease Serology Collection (Public Health Ontario)
- Reporting Requirements for Physicians
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Lyme disease is designated as a disease of public health significance in Ontario. Suspected or confirmed cases of Lyme disease are reportable to local public health under the Ontario Health Protection and Promotion Act and must be communicated to Wellington-Dufferin-Health Public Health.
- Patient Resources
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Avoiding tick-bites, making ticks checks part of routines, and early detection can decrease the risk of Lyme disease. Clinical management should include patient education on these items. The following resources can be shared:
- Additional Resources
Partially adapted from Simcoe Muskoka District Health Unit Lyme Disease webpage for Health Professionals