The short answer
Technically yes — cats can be exposed to Borrelia burgdorferi and develop antibodies — but they almost never get sick from it. Per the Cornell Feline Health Center, no naturally acquired clinical case of feline Lyme disease has been documented outside the laboratory in North America. So in practice, “Can my cat get sick from Lyme?” is a no.
The biology behind why cats are different
Lyme disease in dogs and humans is caused by Borrelia burgdorferi, a corkscrew-shaped bacterium transmitted by infected blacklegged ticks. In dogs, about 5–10% of exposed individuals develop clinical disease (lameness, fever, lethargy, swollen joints, sometimes Lyme nephritis). In humans, the proportion is higher.
Cats are an outlier. Multiple academic and veterinary references converge on the same picture:
- Cats can be experimentally infected in laboratory settings.
- Cats in tick-endemic regions sometimes test positive for Borrelia antibodies — confirming exposure to infected ticks.
- But naturally-acquired clinical Lyme disease in domestic cats hasn’t been documented in North America.
The exact reason is not fully understood. The current best explanation is a combination of cat immune system characteristics and feeding-time differences — cats often groom ticks off before the 24–48 hours that Borrelia typically needs to transmit.
So why don’t we screen cats for Lyme?
Because the test wouldn’t change what we do. There is no validated in-clinic feline equivalent of the 4DX SNAP test. If a tick-borne disease is suspected in a cat based on symptoms, we send out PCR or specific serology — but routine annual screening for Lyme antibodies in healthy cats has no clinical value, since the antibodies don’t predict disease and we wouldn’t treat based on them.
For dogs, the calculation is different.
What cats actually do get from ticks
The risks for a Halton cat in 2026 are:
1. Tick paralysis (uncommon)
Engorged female Dermacentor ticks (and occasionally Ixodes) secrete a neurotoxin during feeding. Affected cats develop ascending hind-limb weakness, voice change, and breathing difficulty. Removing the tick almost always resolves it.
2. Cytauxzoonosis (watchlist disease, not yet established in Ontario)
Cytauxzoon felis is carried by lone star ticks and American dog ticks. It kills 40% of treated cats. Both vectors are expanding northward, but neither is established in Ontario yet.
3. Anaplasmosis (rare in cats)
Anaplasma phagocytophilum — same vector as Lyme — has been reported in cats but is uncommon and typically mild.
4. Tick toxicity from dog products (the realistic emergency)
The most likely tick-related emergency in a multi-pet Halton household isn’t a tick-borne disease in the cat. It’s permethrin poisoning from contact with a dog treated with K9 Advantix II or a similar product. Cats lack the liver enzyme to metabolize permethrin and can develop tremors, seizures, and death within hours.
For more on this, see our posts on K9 Advantix II safety in cats and tick exposure in cats.
5. The household courier role
Cats groom unattached ticks off their fur, which means the ticks they bring indoors are often crawling and unattached — and more likely to bite a human elsewhere in the house. Children sitting on floors and furniture are particularly vulnerable. So a tick on the cat is a household risk signal even if the cat itself never gets sick.
Should my cat be on tick prevention?
Yes for outdoor and indoor-outdoor cats. Yes for strictly indoor cats in households where the dog is bringing ticks indoors. Cat-safe options include NexGard Combo, Revolution Plus, Bravecto Plus, and Credelio Cat. We’ll match the product to your cat’s lifestyle.
The product choice is more important for cats than for dogs because the dangerous products (permethrin) overlap with what’s commonly recommended for dogs. Always confirm a product is labelled for cats before applying.
Symptoms to watch for in a cat after a tick bite
Even though Lyme is unlikely, a few signs warrant a call:
- Lethargy or hiding behaviour out of character
- Fever (warm ears, dull coat)
- Decreased appetite
- Pale gums or jaundice (yellow tinge to gums or eye whites) — particularly important if eTick identifies the tick as a lone star or American dog tick
- Voice change or weakness in the back legs (possible tick paralysis)
For the full action plan, see I found a tick on my cat — what do I do.
For the bigger picture, see our 2026 field guide on ticks in Halton.
Key takeaways
- Cats can be exposed to Borrelia burgdorferi but almost never develop clinical Lyme disease.
- Per Cornell, no naturally acquired clinical case has been documented outside the lab in North America.
- We don’t routinely screen cats for Lyme — there’s no validated in-clinic test and antibodies don’t predict disease.
- Cats do face other tick-related risks: tick paralysis, cytauxzoonosis (watchlist), permethrin toxicity from dog products, and a courier role for human-bound ticks.
- Outdoor cats and cats in dog households should be on cat-safe tick prevention.
- Watch for lethargy, fever, pale gums, or jaundice for 2 weeks after a tick bite — call us if any develop.
References
- Cornell Feline Health Center — feline Lyme disease.
- Companion Animal Parasite Council — Lyme disease guidelines.