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



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., behavior 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 tick bites in an area where ticks carry the B. burgdorferi bacteria, Ontario Lyme Disease Risk Areas Map
  • Occupations/activities in tall grass or wooded areas where ticks reside
  • Prophylaxis after a tick bite is recommended according to the attached 2015 LGL Lyme Disease Prophylaxis Algorithm


Diagnosis & Laboratory Testing

Diagnosis is primarily based on clinical and epidemiological findings. Laboratory testing is used to support clinical suspicion of Lyme disease.
Serological evidence using the two-tier enzyme-linked immuno-sorbent assay (ELISA) and Western Blot criteria (as described by the guidelines of the Canadian Public Health Laboratory Network) is used to support clinical diagnosis of Lyme disease.

For further information about human diagnostic testing, contact the Public Health Ontario Laboratories or refer to the Labstract.

Indications and Limitations

• When patients are treated very early in the course of illness, antibodies may not develop.

• If serological testing was done for early localized disease initial negative serological tests in patients with skin lesions suggestive of EM should have testing repeated after 2 to 4 weeks, however if patients are treated during this time, subsequent testing may be negative.

• The Western blot (particularly only IgM reactivity) may yield a false positive result.

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).


Patient Information

Patient Fact Sheet



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


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: 26/10/2017