A growing concern in Canada

Lyme disease in dogs is caused by Borrelia burgdorferi, a bacterium transmitted by the black-legged tick (Ixodes scapularis), also known as the deer tick. Lyme disease in dogs is becoming increasingly common in parts of Canada, including Quebec. While it cannot be passed directly from dogs to humans, the presence of infected ticks poses a shared risk to both pets and people.

Signs and symptoms in dogs

Only 5–10% of infected dogs show clinical symptoms, which usually appear 2 to 5 months after a tick bite:

• Lameness due to joint inflammation (arthritis)
• Swollen lymph nodes
• Fever and lethargy
• In rare cases: kidney, heart, or nervous system involvement

Transmission and risk factors

• Ticks must remain attached for 24–48 hours to transmit the bacteria
• Once infected, dogs can remain long-term carriers
• Dogs in wooded, grassy, or even urban environments are at risk

What about cats?

Cats do not develop Lyme disease, but they can carry ticks in their fur, increasing the risk of exposure for dogs and humans.

How is it diagnosed?

• A quick blood test can detect antibodies to the C6 peptide specific to Borrelia
• The test is reliable at least 3–5 weeks after suspected exposure
• If the result is positive, further tests (urinalysis, antibody levels) may be needed

Treatment options

• Antibiotics are recommended if symptoms are present or if the kidneys are affected
• Some dogs may remain carriers even after treatment
• A follow-up blood test six months later helps evaluate treatment response

Prognosis

• Good if the infection affects only the joints
• Guarded if the kidneys are involved

Effective prevention strategies

• Monthly tick preventives (topical or oral)
• Daily coat inspections after walks, especially in risk areas
• Use a tick remover tool (e.g., tick twister) to remove attached ticks gently
• Maintain your yard: cut grass short, avoid bird feeders
• Vaccination is available and recommended in endemic areas
• Annual screening is advised even for dogs on prevention

Speak to your veterinarian

As Lyme disease spreads, a tailored prevention plan is essential. Ask your veterinarian which tick control products and testing schedules are right for your dog.