07/02/2026
LYME DISEASE
Lyme disease in dogs is a bacterial infection transmitted by black-legged (deer) ticks. Symptoms typically appear two to five months post-bite and include fever, lameness, swollen joints, and lethargy. It is treated with a four-week course of antibiotics, though prevention through tick control is the best defense. Here are the key things you need to know about Lyme disease (caused by the bacterium Borrelia burgdorferi) in dogs:
Symptoms
Interestingly, most infected dogs never show any signs of illness. For those that do, symptoms usually do not appear until months after the tick bite. The most common clinical signs include: Shifting lameness: Limping that moves from one leg to another. Joint pain: Swollen, warm, or painful joints (sometimes described as walking on eggshells).Systemic symptoms: High fever, lethargy, loss of appetite, and swollen lymph nodes. Kidney complications: In rare but severe cases, the bacteria can cause Lyme nephritis (kidney disease), which can be fatal.
Diagnosis
Because many dogs carry antibodies without being clinically ill, a positive blood test alone does not confirm active Lyme disease. Veterinarians diagnose the condition using a combination of a physical exam, clinical history (tick exposure), and specific antibody tests (like the C6 or Multiplex tests) to assess the severity or stage of the infection.
Treatment
Because the disease is bacterial, it is treated with a course of antibiotics—most commonly doxycycline—usually spanning four weeks. If caught early, dogs often respond very quickly to the medication. However, if left untreated, the infection can cause chronic, permanent joint damage or fatal kidney failure
Prevention
Tick removal: Check your dog thoroughly after they have been in wooded or grassy areas. If you find a tick, remove it promptly using fine-tipped tweezers by pulling straight up.Year-round preventatives: Consult your veterinarian about consistent use of oral, topical, or collar tick preventatives.Vaccination: In areas where Lyme disease is highly prevalent (such as the Northeast and upper Midwest US), your vet may recommend a Lyme vaccine for your dog.