Explainer

Ticks and Lyme Disease in Dogs and Cats

Ticks spread Lyme disease, ehrlichiosis and anaplasmosis. The signs in dogs, how quickly ticks transmit disease, testing, and why vets recommend year-round tick control.

Updated October 2026 · 7 min read · By the Hushku editorial team · 2 sources

Short answer

Ticks can spread several diseases to dogs and cats, including Lyme disease, ehrlichiosis and anaplasmosis. Lyme bacteria usually need 24 to 48 hours of tick feeding to transmit, so checking your pet daily and removing ticks promptly helps. The Companion Animal Parasite Council recommends year-round tick control for all dogs and cats. Most dogs exposed to Lyme never get sick; those that do usually have fever and lameness that shifts between legs.

Key facts

Lyme bacteria usually need 24–48 hours of tick feeding to transmit.
Ehrlichia and Rickettsia can transmit within 3–6 hours.
CAPC recommends year-round tick control for all dogs and cats.
Never use dog tick products on cats; permethrin is toxic to cats.

Definition

Lyme disease (Lyme borreliosis) is a bacterial infection caused by Borrelia burgdorferi, spread by the bite of infected blacklegged (deer) ticks. Ticks also spread other infections, together called tick-borne diseases.

Ticks are blood-feeding parasites that wait in long grass and undergrowth and climb onto passing animals. They're most active in spring and autumn in many areas, but can be active whenever temperatures are above freezing.

According to CAPC, ticks transmit a range of infections to dogs and cats, including Ehrlichia, Anaplasma, Rickettsia (Rocky Mountain spotted fever), Babesia and, in cats, Cytauxzoon felis. Some of these also infect people. Heavy tick burdens can cause anaemia, and some ticks cause tick paralysis.

Timing matters. CAPC notes Lyme bacteria can take 24 to 48 hours of feeding before infection passes on, while Ehrlichia and Rickettsia can transmit within 3 to 6 hours. Prevention products that kill ticks quickly are the best protection.

Signs and symptoms

Often no signs at all: most dogs exposed to Lyme never get sick
Lameness that shifts from one leg to another
Swollen, painful joints
Fever, lethargy and poor appetite
Swollen lymph nodes
Rarely, kidney disease (Lyme nephritis), with vomiting, thirst and weight loss, which is serious
Other tick diseases: bruising, nosebleeds, pale gums or fever

Causes and risk factors

Bites from infected ticks
Walking in long grass, woodland and brush, especially in tick-heavy regions
Missed or late doses of tick preventive

Treatment

A course of antibiotics, usually doxycycline, for around 4 weeks for Lyme disease
Pain relief for sore joints
Hospital care for dogs with kidney involvement
Specific treatments for other tick-borne infections

Prevention

Year-round tick control for every dog and cat, as CAPC recommends
Check your pet daily for ticks after walks, especially the head, ears, neck, armpits and between the toes
Remove ticks promptly with fine tweezers or a tick tool
A Lyme vaccine is available for dogs in high-risk areas; ask your vet
Keep grass short and clear leaf litter in your garden

Testing

Many vets use an in-clinic blood test once a year that screens for heartworm and tick-borne infections at the same time (such as the SNAP 4Dx). A positive Lyme result shows exposure, not necessarily disease; your vet will decide whether treatment is needed based on signs and further tests, such as a urine protein test.

Cats and ticks

Cats rarely get sick from Lyme disease but can get other tick-borne infections, including cytauxzoonosis in parts of the US, which is often fatal. Never use dog tick products on cats: some contain permethrin, which is highly toxic to cats.

Can I catch Lyme from my dog?

Not directly. People get Lyme from tick bites, not from dogs. But dogs can carry ticks into the home, so tick control protects your family too.

Free tools for this

Puppy and kitten vaccine due date calculator

Sources

We check guides against veterinary sources and update them when guidance changes. How we write and review.

Questions.

Should I test a tick I removed from my dog?

It's usually not necessary. Monitor your dog for signs, and mention the bite at your next vet visit or sooner if your dog seems unwell.

Can dogs get Lyme disease twice?

Yes. Infection doesn't give lasting immunity, so ongoing prevention matters.

Is the Lyme vaccine worth it?

It may be recommended for dogs in high-risk areas, alongside tick control, not instead of it. Ask your vet about the risk where you live.