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Veterinary Teaching Hospital

Lyme Disease

Dog paw with attached tick.

What is Lyme disease?

Lyme disease, the most common vector-borne disease (transmitted by insects or arthropods) in people, is caused by corkscrew-shaped bacteria, Borrelia burgdorferi, carried by ticks that transmit the infection when they feed on animals and humans.

In the United States, Lyme disease occurs predominantly on the Pacific Coast, the Midwest, and Atlantic Coast states. About 75% of dogs living in endemic regions are exposed to infected ticks, but only a small percentage develop signs of disease.

Infected ticks must feed for about 24 hours to transmit the bacteria to a susceptible animal, so quick removal of ticks from your pet reduces the chance of infection.

Can I get Lyme disease from my pet?

If your pet has been diagnosed with Lyme disease you are not at risk of becoming infected directly from your animal. The bacteria increase to high levels in the blood of wildlife, but humans and domestic animals develop only low levels of the bacteria in their blood and at not high enough to infect a feeding tick.

What are the symptoms of Lyme disease in dogs?

The most common sign of Lyme disease in dogs is arthritis, which causes sudden lameness, pain, and sometimes swelling in one or more joints. Other signs may include fever, lack of appetite, dehydration, inactivity, and swollen lymph nodes.

In severe cases, the infection can cause kidney failure and death, although this does not occur commonly in dogs.

Humans often show a skin rash that looks like a target, but this is rarely seen in infected dogs.

How is Lyme disease diagnosed in dogs?

A diagnosis of Lyme disease is usually made based upon a history of being in an endemic area, signs of arthritis, and favorable response to treatment.

A blood test can measure antibodies to the bacteria, but many dogs that live in endemic regions will have a positive result. A positive only confirms the dog was exposed to Borrelia burgdorferi, but not all exposed dogs show signs of disease.

How are dogs infected with Lyme disease treated?

Lyme disease is easily treated with antibiotics, and symptoms usually regress rapidly in response to treatment. Untreated, the disease becomes chronic and can cause kidney damage.

How can you prevent a dog from becoming infected with Lyme disease?

The best method of preventing Lyme disease is to avoid tick-infested areas, especially in the spring when the young ticks are most active.

When returning from a tick-infested area, do a thorough search for ticks on yourself and your animals. Ticks should be removed carefully with tweezers, pinching the tick near the point they enter the skin.

There are also many highly effective veterinary products that will kill ticks on your dog before they can transmit the bacteria. Early removal of ticks reduces the chance of transmission.

A vaccine has been approved for use in dogs for Lyme disease prevention, but most authors of veterinary articles on Lyme disease do not recommend vaccinating dogs in non-endemic areas. Not all authors agree on how effective the vaccine is in preventing Lyme disease or whether it should be given in endemic regions. For more information about tick control products or Lyme disease, consult your veterinarian.

What should I do if I suspect my dog may have Lyme disease?

What should I do if I suspect my dog may have Lyme disease?

If your dog is showing symptoms of Lyme disease, contact your veterinarian or the WSU Veterinary Teaching Hospital at 509-335-0711.


This information is not meant to be a substitute for veterinary care. Always follow the instructions provided by your veterinarian. Washington State University assumes no liability for injury to you or your pet incurred by following these descriptions or procedures.