Glossary
Lyme disease
A bacterial infection spread by blacklegged ticks that causes fever and joint pain in some dogs, and rarely damages the kidneys.
Also called: canine Lyme disease, borreliosis, Borrelia burgdorferi, tick-borne Lyme
Lyme disease is caused by the bacterium Borrelia burgdorferi, carried by blacklegged ticks, also called deer ticks. A tick usually needs to stay attached for a day or longer to pass it on. It is common in the northeastern and upper midwestern United States and in parts of Europe.
Most infected dogs never get sick. Those that do may have fever, swollen joints, shifting leg lameness, tiredness and loss of appetite, sometimes weeks or months after the bite. A small number develop a dangerous kidney disease.
A veterinarian can screen for exposure with a blood test and discuss a vaccine for dogs in high-risk areas. Year-round tick control and checking your dog after outdoor time cut the risk. Dogs do not pass Lyme directly to people, but they can bring ticks into the home.
Last reviewed November 8, 2026