Lyme disease in dogs most commonly manifests by a sudden onset of lameness and inflammation of the joints. Some dogs will experience other symptoms including weakness, lethargy, loss of appetite and weight, or fever. Lameness is generally temporary and abates once treated with antibiotics, however, in some cases, it can become more severe or even chronic.
Lyme can also cause more serious or even fatal conditions in dogs such as kidney, nervous system, or heart problems (acute cardiac syndrome is known to be caused by Lyme, but is rare). Symptoms that may indicate a more serious condition include: vomiting, diarrhea, extreme lack of appetite or weight loss, increased urination and thirst, fluid buildup (e.g., a swollen belly, legs, or lymph nodes), difficulty breathing, sensitivity to touch, or a stiff walk with arched back. Be sure to contact your veterinarian if your dog is experiencing any of these symptoms.
Most dogs exposed to Lyme never become ill. They will host the bacteria, and may also host other tick-borne diseases such as ehrlichiosis and babesiosis, without ever showing any clinical reaction at all. Lyme disease is always more difficult to treat as the duration of the infection lengthens, so early diagnosis and treatment are key.
There is evidence that Lyme disease is more common among younger dogs than mature dogs and that certain species are more vulnerable than others (retrievers for example).
There are several antibiotics available to treat Lyme disease in dogs. The typical course is four weeks and typically the condition is resolved without further complications or additional treatment required. In some cases, as in humans, the symptoms do not cease after treatment and your dog may continue to experience pain or lameness. Speak with your vet.
The best course is always prevention.
Watch where they wander. Avoid allowing your dog (or other pets) to roam in tick-infested environments or habitats where Lyme is common. When walking or hiking, keep your pet on leash in the middle of the trail and avoid wandering into brushy or wooded areas.
Tick check. Be sure to groom and bathe your dog regularly, checking for ticks both by sight and by feel.
Consider repellent and/or vaccines. There are a number of tick repellent sprays, collars, and topical products that can be used to kill or keep ticks away. There are also Lyme vaccines available for dogs. Note: According to the CDC, the Lyme vaccines do NOT prevent against other tick-borne diseases such as Rocky Mountain spotted fever or babesia. Speak with your veterinarian about your options.
Read more about Lyme disease in dogs from the Baker Institute for Animal Health at Cornell University.