Lyme disease surveillance in Canada: 2009 to 2019 (infographic)

Data from the Canadian Notifiable Disease Surveillance System and the Lyme Disease Enhanced Surveillance System of the Public Health Agency of Canada

What is Lyme disease?

Lyme disease is the most reported tick-borne zoonoses in Canada. It is caused by the bacteria Borrelia burgdorferi and transmitted by western blacklegged ticks (Ixodes pacificus) in British Columbia and blacklegged ticks (Ixodes scapularis) in central and eastern Canada.

It is a multisystem infection that can affect the skin, heart, joints and nervous system. Most people bitten by a Borrelia burgdorferi-infected tick will develop a skin rash (erythema migrans), which may be accompanied by flu-like symptoms. If left untreated, the bacteria can spread through the blood and cause multiple secondary skin lesions, cardiac symptoms (carditis, atrioventricular heart block, arrhythmia and palpitations) and neurologic symptoms (Bell's palsy and meningitis). Months to years post-infection, late disseminated Lyme disease can manifest with single or recurrent joint arthritis episode(s).

What are the trends?

• 10,150 reported human cases of Lyme disease (2009−2019)
• 71% confirmed cases
• 29% probable cases

According to national data, 2,634 Canadians were reported with Lyme disease in 2019 compared to 144 in 2009.

Of the 363 human cases acquired outside Canada:

• 57% exposed in the USA
• 41% exposed in Europe

Average annual incidences of reported cases per 100,000 populations are presented on the map.

Seasonality

Higher number of cases acquired in summer months:

• June, 20% of cases
• July, 35% of cases
• August, 19% of cases

Demographic characteristics

Age groups at higher risks:

• Incidences (cases per 100,000 population) were higher in children aged 5–9 years (45.0) and in adults aged 65–69 years (74.3)
• 57% of all reported cases occurred among adults aged 50−84 years

What are the reported Lyme disease symptoms for locally acquired cases?

Early localized stage

• 75% single erythema migrans skin rash

Early disseminated stage

• 4% cardiac symptoms (carditis, atrioventricular heart block, arrhythmia and palpitations)
• 8% Bell's palsy (facial paralysis)
• 19% other neurologic symptoms

Late disseminated stage

• 34% single or recurrent joint arthritis episode(s)

Related Links

• Surveillance for Lyme disease in Canada: 2009–2019
• Lyme disease case definition
• Information about at-risk areas
• Lyme disease for health professionals
• More information on ticks

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