Lyme Disease Information for Health Care Professionals
Report Lyme disease
Lyme disease is reportable to the Medical Officer of Health under the Health Protection and Promotion Act. Report all clinical diagnoses of Lyme disease by the next working day:
Data collected helps us and the province to monitor disease, identify risk factors and to provide preventative education. Reporting can only be completed by:
- Health care professional
- Acute care facility
Cause of Lyme disease
Lyme disease is transmitted through a bite from a blacklegged tick infected with Borrelia burgdorferi. Blacklegged ticks must be attached for 24-36 hours to transmit Lyme disease. Not all ticks found on humans are blacklegged ticks and not all blacklegged ticks are infected with the bacteria that causes Lyme disease. Learn about tick identification.
See tick information for health care professionals.
Assessing for early Lyme disease
Lyme disease typically presents within three to 30 days of a bite from an infected blacklegged tick. Symptoms for Lyme disease may appear in overlapping stages. Signs and symptoms of early Lyme disease include:
- Fever
- Arthralgias
- Myalgias
- Headache
- Presence of erythema migrans (typically within seven days of initial bite and equal to or greater than five cm)
Erythema migrans
Erythema migrans appearance can differ depending on skin colour. Approximately 70 per cent of individuals with possible early Lyme disease present with erythema migrans. Health care professionals should not rule out Lyme disease based solely on the absence of erythema migrans.
In patients with a potential blacklegged tick exposure in a Lyme risk area, including Niagara, one or more lesion(s) consistent with erythema migrans greater than five cm in diameter is sufficient to diagnose early Lyme disease. Most patients with a single erythema migrans lesion are seronegative at the time of presentation, so early Lyme disease should be treated without laboratory testing.
Laboratory testing
Two-tiered serology is the current laboratory test available for Lyme disease. Clinical decisions to order serology and interpretation of test results should be considered in the context of both clinical presentation and duration of symptoms.
Treatment for early Lyme disease
The preferred first line treatment of patients with early Lyme disease is:
- Adults: Doxycycline 100 mg twice a day for 10 days
- Children: Doxycycline 4.4 mg / kg per day (maximum of 100 mg per dose) in two divided doses for 10 days. Patients and their guardians should be counselled that there is a growing consensus that doxycycline use is safe in young children, but that additional safety data are still being collected.
More information
For further information on diagnosis, lab interpretations and treatment for Lyme disease, review:
- Infectious Diseases Society of America, Clinical Practice Guidelines
- Public Health Ontario, Lyme Disease Testing
- Lyme disease: Public Health Agency of Canada Lab Diagnostics
- Public Health Agency of Canada: Lyme Disease
More resources
If you have any questions, call 905-688-8248 or 1-888-505-6074 ext. 7330.
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