Ticks and tick-borne diseases in Canada

Flashcards cover tick species and transmission, Ontario risk, ACVIM consensus on Lyme disease, screening and monitoring, clinical signs, and tick control products.

What is the scientific name of the Lone Star Tick?

Amblyomma americanum transmits:

• Ehrlichia ewingii

• Cytauxzoon felis

What is the scientific name of the Gulf Coast Tick?

Amblyomma maculatum

What is the scientific name of the Rocky Mountain Wood Tick?

Dermacentor andersoni transmits:

• Rickettsia rickettsii

• Francisella tularensis

What is the scientific name of the American Dog Tick?

Dermacentor variabilis transmits:

• Rickettsia rickettsii → rocky mountain spotted fever

• Francisella tularensis

• Cytauxzoon felis

What is the scientific name of the Western Black-legged Tick?

Ixodes pacificus transmits:

• Borrelia burgdorferi → lyme

• Anaplasma phagocytophilum

What is the scientific name of the Deer Tick (Black-legged Tick)?

Ixodes scapularis transmits → lyme

What is the scientific name of the Brown Dog Tick?

Rhipicephalus sanguineus transmits:

• Babesia canis

• Ehrlickia canis

• Anaplasma platys

• Rickettsia rickettsii

Which tick is currently most likely to be found in Ontario?

• Dermacentor variabilis → american dog tick

• Ixodes scapularis → black legged/deer tick

Which two Ixodes species transmit Borrelia burgdorferi (Lyme disease) in North America?

Ixodes scapularis and Ixodes pacificus

Which Dermacentor species is associated with Rocky Mountain spotted fever (RMSF) and found in North America?

Dermacentor variabilis (and Dermacentor andersoni in some regions)

True or False: In Ontario, there have been RMSF cases diagnosed in dogs in 2025 with dogs that had not travelled.

True

Which tick is commonly associated with RMSF and can cause tick paralysis (rare) in Canada?

Dermacentor variabilis (American dog tick) and Dermacentor andersoni (Rocky Mountain wood tick)

How long must Ixodes scapularis be attached to transmit Borrelia burgdorferi?

Approximately 36 hours or more

When does seroconversion to Borrelia burgdorferi typically occur in dogs after infection?

3-5 weeks

What proportion of B. burgdorferi–infected dogs become clinically ill?

About 5-10%; 90-95% never become clinical

According to the ACVIM 2018 consensus, should dogs in Borrelia endemic areas receive year-round tick control?

Yes; all dogs should have adequate tick control year-round

Is there a universal consensus on Lyme vaccination for dogs in endemic areas according to ACVIM 2018?

No; some panelists supported vaccination, but consensus was not reached; vaccination not recommended for sick or proteinuric dogs

Does Lyme vaccination interfere with Borrelia burgdorferi antibody testing?

No; vaccination does not interfere with qualitative antibody testing

What test is recommended to be included with annual wellness exams for healthy dogs in endemic areas?

Qualitative Borrelia burgdorferi antibody assay (often via 4Dx Plus panel)

What test is useful for monitoring response to treatment for Lyme disease in dogs?

Quantitative C6 (C6 titer) testing

If a healthy dog tests positive for Borrelia burgdorferi, what monitoring strategy does ACVIM advise?

Monitor for clinical signs and for proteinuria over 12 months; treat if proteinuric or signs develop

What is the recommended management for a dog that is fully engorged with Ixodes scapularis?

Evaluate for Lyme disease and proteinuria for 6 months; serology now and in 6-8 weeks; consider tick PCR for B. burgdorferi

What is the recommended management if a dog tests positive for Anaplasma or Ehrlichia but has no clinical signs?

Check CBC; if abnormal, treat (doxycycline for 1 month); if normal, recheck in about 1 month

What are typical clinical signs of Borrelia burgdorferi (Lyme disease) in dogs?

Fever, anorexia, lethargy, polyarthritis with shifting leg lameness, joint swelling; possible lymphadenomegaly, splenomegaly, hepatomegaly

Which factors are driving changes in the distribution of Ixodes scapularis in Ontario?

Bird migration, changes in deer populations, reforestation, climate change

What is the approximate reported seroprevalence of Borrelia burgdorferi in dogs across the USA (2013-2019) in various regions?

Varies by region; ranges from 0% to over 5% in some areas per surveillance data

Name an endemic host for Ixodes scapularis larvae and nymphs in Ontario.

White-footed mouse (Peromyscus leucopus) for larvae and nymphs; white-tailed deer for adults

Which tick is known to be a primary vector of Cytauxzoon felis and Ehrlichia ewingii in parts of the USA?

Amblyomma americanum (Lone Star Tick)

Which tick is the primary vector for Babesia canis, Ehrlichia canis, Anaplasma platys, and Rickettsia rickettsii in some regions?

Rhipicephalus sanguineus (brown dog tick)

Which tick control products are examples of monthly topicals for dogs?

Examples include Frontline (fipronil), Revolution (selamectin), NexGard (afoxolaner), Bravecto (fluralaner) with varying dosing intervals

What is the active ingredient in Bravecto (dog oral chewable for fleas and ticks)?

Fluralaner

What is the active ingredient in NexGard (dog oral chewable for fleas and ticks)?

Afoxolaner

What is the active ingredient in Simparica (dog oral chewable for fleas and ticks)?

Sarolaner

What is the active ingredient in Credelio (dog oral chewable for fleas and ticks)?

Lotilaner

What is the active ingredient in the Seresto collar?

Flumethrin + Imidacloprid

What is the purpose of the Seresto collar?

Prevents ticks and fleas on dogs and cats for up to 8 months