Lyme Disease

Reporting Obligations

Individuals with suspect or confirmed cases must be reported to the Thunder Bay District Health Unit by the next working day by fax, phone or mail.

  • Fax: (807) 625-4822
  • Phone: 625-8318 or toll-free at 1-888-294—6630, ext. 8318
  • Mail: 999 Balmoral Street, Thunder Bay, ON P7B 6E7



June 25, 2018 - Health Care Provider Update



Aetiologic Agent:

Lyme disease is a tick-borne zoonotic disease caused by the bacterium, Borrelia burgdorferi (B. burgdorferi), a spirochete first identified in North America in 1982.

Clinical Presentation:

Lyme borreliosis is generally divided into three stages in which infected persons may experience any of the following symptoms:

Early localized disease

Erythema migrans (EM) or “bull’s eye” rash at the site of a recent tick bite, fever, malaise, headache, myalgia, neck stiffness, fatigue, and arthralgia

Early disseminated disease

Multiple EM in approximately 15% of people occurs several weeks after infective tick bite, cranial nerve palsies, lymphocytic meningitis, conjunctivitis, arthralgia, myalgia, headache, fatigue, carditis (heart block); and

Late disease

May develop in people with early infection that was undetected or not adequately treated. Involves the heart, nervous system and joints; arrhythmias, heart block and sometimes myopericarditis; recurrent arthritis affecting large joints (i.e., knees); peripheral neuropathy; central nervous system manifestations – meningitis; encephalopathy (i.e., behaviour changes, sleep disturbance, headaches); and fatigue.

Modes of transmission:

Bite by a black-legged tick carrying B. burgorferi bacteria that has been attached for at least 24 hours.

Incubation Period:

For early localized disease, from 3 - 30 days after tick exposure with a mean of 7 - 10 days; early stages of the illness may not be apparent and the person may present with later manifestations.

Period of Communicability:

There is no evidence of person to person spread.


Risk Factors/Susceptibility

  • Persons with history of exposure to geographic areas where blacklegged ticks are common (see the Ontario Lyme Disease Risk Areas Map)
  • Occupations/activities in tall grass or wooded areas where ticks reside


Diagnosis & Laboratory Testing

Lab testing is not sensitive in early localized disease, which typically presents with erythema migrans and flu-like symptoms 1-2 weeks following the bite of an infected black-legged tick. 

Early localized Lyme disease is a clinical diagnosis, and is still reportable to TBDHU under the Health Protection and Promotion Act even if lab testing is negative. 

Lab testing is sensitive and specific in early disseminated and late Lyme disease.

Testing Information & Requisition


Treatment & Case Management

Treatment is under the direction of the attending health care provider.

Lyme disease treatment guidelines are available from Public Health Ontario;  Technical report: Update on Lyme disease prevention and control (June 2016).

Download the Lyme disease health care provider factsheet and algorithm for TBDHU (updated June 2018).

Patient Information

Patient Fact Sheet



1. Ministry of Health and Long Term Care, Infectious Diseases Protocol, 2016.  Appendix A (2015) and Appendix B (2017)


Additional Resources

1.  Public Health Ontario.. "Technical Report: update on lyme disease prevention and control. 2nd edition."

2. PHAC. CCDR Report May 29, 2014, "Clinical aspects of Lyme disease."

3. Ministry of Health and Long Term Care "Arthropod Identification Forms’."

4. PHAC. "Lyme disease and other tick-borne diseases: Information for health professionals."

5. CDC. "Division of Vector-Borne Diseases (DVBD)."


Last Updated: 11/04/2019