Lyme Disease in Dogs: Signs, Testing and Prevention

By Tailwisp Editorial TeamUpdated October 17, 20263 min read

Lyme disease is best known in people, but dogs are bitten too, and some become seriously ill.

How it spreads

The bacterium Borrelia burgdorferi is carried by blacklegged (deer) ticks. A tick generally needs to stay attached for a day or more to transmit infection, which is why prompt removal helps. See ticks on dogs.

Where it occurs

It is most common in the northeastern and upper midwestern United States, parts of the Pacific coast, and in regions of Europe and Asia. Risk changes over time as tick ranges shift, so check with your vet.

Signs

Most dogs show no signs. When they do, they may appear two to five months after the bite:

• Fever and lethargy
• Shifting-leg lameness and swollen, painful joints
• Loss of appetite
• Swollen lymph nodes
• Kidney involvement, a rare but serious form called Lyme nephritis with vomiting, weight loss, increased thirst and swelling. See kidney disease in dogs

See why is my dog limping.

Diagnosis

Blood tests, such as the in-clinic C6 antibody test or lab quantitative tests, show exposure. A positive result does not always mean illness, so vets combine tests with signs, bloodwork and urinalysis to decide whether to treat.

Treatment

Doxycycline for around four weeks is the usual treatment. Most dogs with joint signs improve within days. Dogs with kidney involvement need intensive care. Even after treatment, some dogs remain positive on tests, and relapse or reinfection can occur.

Prevention

1. Use tick preventives all year where ticks are active. See dog flea, tick and heartworm medications.
2. Check for ticks after walks and remove them promptly.
3. Consider vaccination in high-risk areas, as your vet advises.
4. Keep yards tidy and avoid tall brush.
5. Screen yearly with a combination test.

Do ticks on dogs risk people?

Dogs do not spread Lyme directly to people, but they can bring infected ticks home. Check yourself and your family after outdoor time, and ask your doctor if you have concerns.

Questions to ask your vet

Ask about local Lyme prevalence, whether your dog should be vaccinated, how often to test and which tick product is best. Ask what to do if your dog tests positive without signs.

Common mistakes

• Pulling ticks off roughly
• Skipping prevention in winter
• Assuming a positive test means disease
• Ignoring shifting lameness

Troubleshooting

• My dog tested positive but looks well: discuss monitoring with your vet.
• My dog's lameness returned: book a recheck.
• My dog has increased thirst: ask about a urine test for kidney involvement.

A simple plan

1. Use tick prevention.
2. Check and remove ticks.
3. Test yearly.
4. Treat when advised.

Real-life examples

A retriever with a limp improves quickly on doxycycline. A terrier with no signs tests positive on annual screening and is monitored. A beagle with kidney involvement needs hospital care. Early checks matter.

Staying consistent

Year-round tick control is the best defense.

What a positive test means

Antibodies show that your dog has been exposed, not necessarily that he is sick. Your vet will consider signs, bloodwork and a urine protein check. Some veterinarians treat only dogs with signs or protein loss, while others treat all positives, so ask what they recommend and why.

Lyme vaccination

Vaccines are available and are used in high-risk areas, but they are not a substitute for tick control. Discuss your dog's exposure, age and health with your vet to decide. Keep checking and removing ticks, since vaccines do not protect against other tick-borne diseases.

The takeaway

Lyme disease is preventable and usually treatable. Use tick control, check daily and test yearly.

This article is general educational information, not veterinary advice. Every dog is different. If your dog is unwell, or you are unsure about a symptom, diet change or medication, contact your veterinarian.