Lyme Disease

NCCID Disease Debriefs provide Canadian public health practitioners and clinicians with up-to-date reviews of essential information on prominent infectious diseases for Canadian public health practice. While not a formal literature review, information is gathered from key sources including the Public Health Agency of Canada (PHAC), the USA Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO) and peer reviewed literature.

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What are important characteristics of Lyme disease?


Lyme disease is a bacterial infection caused by Borrelia burgdorferi. It spread through the bite of infected ticks. Ticks attach to any part of the human body but are often found in hard-to-see areas. In most cases, the tick must be attached for at least 24 hours before Lyme disease can be transmitted.

Most humans are infected through the bites of immature ticks called nymphs. Nymphs are tinny (less than 2 mm).


Incubation period: 3-30 days after tick bite.

Early signs and symptoms include rash sometimes like a bull’s eye rash (Erythema migrans rash), fever, chills, headache, fatigue, muscle and joints aches and swollen lymph nodes.
If untreated, severe symptoms include severe headaches, facial paralysis (Bell’s Palsy), muscle, joint, tendon and bone aches, heart disorders, neurological disorders.


Typically, clinically symptoms are three pronged.

a) Early localized Lyme disease (within a month)– symptoms include fever, arthralgias, myalgias, headache, the presence of a single, localized skin lesion known as erythema migrans (EM)

b) Early disseminated Lyme disease (less than 3 months)– symptoms such as fatigue and general weakness, cutaneous signs, typical cardiac complications include atrioventricular block, tachyarrhythmias, myopericarditis and myocardial dysfunction, neurological symptoms are aseptic meningitis, radiculopathy, encephalopathy, cranial neuropathy (especially facial nerve palsy), monomeutitis multiplex, subtle cognitive difficulties, motor and sensory radiculoneuropathy. Other manifestations are uveitis, keratitis, conjunctivitis, mild hepatitis, and splenomegaly.

c) In the case of Late Lyme disease (more than 3 months), if it remains untreated, it can last for months and years. Musculoskeletal symptoms could develop such as Baker’s cyst, chronic arthritis, asymetric oligoarticular arthritis (usually affecting knees), transient, migratory arthritis and effusion in one or multiple joints. Neurological symptoms may also be observed such as: subacute mild encephalopathy, affecting memory & concentration, chronic mild axonal polyneuropathy, manifested as distal paresthesias, radicular pain (less common), some rare ones include encephalomyelitis & leukoencephalopathy.

Laboratory Testing:

Two tiered serological testing for antibodies against bacterium causing Lyme disease is recommended.

a) An enzyme immunoassay (EIA) screening test

b) A confirmatory immunoblot (IB) test (if the EIA is positive or equivocal)

Only IgG testing should be performed (not IgM) on patients with Lyme disease for over a month.

Serological tests should not be performed as a test of cure & cannot be used to measure treatment response.


The treatment guidelines for early Lyme disease include (source: Government of Canada-For Health Professionals: Lyme disease-Treatment):


Doxycycline is contraindicated for children less than 8 years old and for pregnant or lactating mothers so the drug of choice is Amoxicillin in this case.
In cases where these are not drug of choice, patients are recommended to use macrolide (azithromycin, erythromycin, clarithromycin).


The best prevention strategy is to protect against tick bites, as there is no human vaccine currently available against Lyme disease.
Lyme disease is not a contagious disease however, people with active Lyme disease should not donate blood as it can a medium of transportation.

What is happening with current outbreak of Lyme disease?

In the year 2017, more than 1,400 cases were reported all across Canada, with 987 cases in the province of Ontario, of which 78 were from Toronto.

Government of Canada statistics below indicate an increase in reported cases over the eight-year period from 2009 -2016.

The map below shows the geographic areas where the risk from tick bites and Lyme disease is known to occur and are called the “risk areas.”


Case have more than doubled in just a year’s time. In, 2017 about 987 total cases of Lyme disease were reported in the province compared to only 388 cases in 2016.
Recently, Public Health Ontario has issued estimated risk areas (geographic communities) for 2018, which can assist local public health units as they conduct Lyme disease case investigations.


In 2017, about 43 confirmed and probable cases were reported, compared to 52 in 2016 and 37 cases from 2014.

Nova Scotia

There has been an upsurge in reported cases of Lyme disease from 247 in 2015 to 326 in 2016 in Nova Scotia.

New Brunswick

About eight laboratory confirmed cases of Lyme disease were reported in 2016.


In years, 2015 and 2016, 14 and 10 Lyme disease cases were reported in Alberta, respectively. All were cases acquired from other provinces where the disease is prevalent.

British Columbia

According to British Columbia Centre for Disease Control, Lyme disease cases have doubled in British Columbia from 21 in 2015 to 40 reported cases in 2016.

What is the current risk for Canadians from Lyme disease?

The risk of contracting Lyme disease is very high across southern Canada during warm weather (Spring & Summer) and especially during outdoor activities such as golfing, hunting, camping, fishing & hiking. Surveillance data indicates that blacklegged ticks are spreading in eastern & central Canada.

What measures should be taken for a suspected Lyme case or contact?


The Government of Canada has developed brief guidelines to help healthcare providers in the management and treatment of Lyme disease infection. These include signs, symptoms, diagnosis, laboratory testing, surveillance, prophylaxis, treatment.

Public Health Ontario has worked with other public health units and Public Health Agency of Canada to develop a Lyme disease case management tool companion guide which identify exposure location, improve case and contact management, provide case counseling, assist with disease management, obtain required data elements under the health protection and promotion act pertaining to the case and facilitate investigation documentation.


Government of Canada developed Lyme disease case definition in 2016 for confirmed case, probable case, and clinical evidence. Since 2009, Lyme disease has been nationally notifiable disease.

In March 2017, The Ministry of Health Long-Term Care Ontario published the provincial case definitions for Lyme disease.


Government of Canada and provincial authorities have laid out guidance to prevent infection from Lyme disease.