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 and tick removal.

Ticks submitted to Niagara Region Public Health for identification are not tested for Borrelia burgdorferi.

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 centimetres)

Erythema migrans

Erythema migrans appearance can differ depending on skin colour. Approximately 70 to 80 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.

Patients with a single erythema migrans skin lesion can be seronegative at the time of initial presentation. A lesion greater than five centimetres in diameter consistent in appearance to erythema migrans in individuals exposed to blacklegged ticks in risk areas such as Niagara is considered confirmation of early localized Lyme disease and should be treated without laboratory confirmation.

Laboratory testing

Public Health Ontario's testing for Borrelia burgdorferi antibodies uses a modified two-tiered testing approach. Clinical decisions to order serology and interpretation of test results should be considered in the context of both clinical presentation and duration of symptoms. Learn about Lyme disease serology testing.

Treatment for early Lyme disease

For guidance on the management of tick bites and investigation of early localized Lyme disease, refer to Ontario Health's clinical guidance resource.

More information

If you have any questions, call 905-688-8248 or 1-888-505-6074 ext. 7330.

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