Lyme disease is a bacterial illness that can affect dogs, cats, horses, wild mammals, and even humans. The bacterium is carried by ticks, most commonly the deer tick and the western black-legged tick, and it is spread by the tick biting the affected host. The deer tick can be found throughout much of the Midwestern and Eastern United States, and the western black-legged tick is the more common cause of Lyme disease in the Western United States. However, recent evidence suggests that the geographic distribution of these ticks is expanding 1. Ticks like to be in areas with lots of trees and tall grass. When looking for a host, they will sit on the tops of tall grasses and jump onto a passing animal or person as they brush against the grass.
Some dogs that are bitten by a tick might not show any signs at all but can be lifelong carriers of Lyme disease. Some of these carriers might show clinical signs later in life, and other dogs might show signs right away. Fever, lethargy, and lameness are the most frequently reported signs. Joints can be especially painful, and some dogs might have a “shifting leg lameness” where they are painful on one leg for three to four days but then appear painful on a different leg a few weeks later. Other clinical signs include a stiff gait, shallow breathing, and being painful to the touch 2. In cases where dogs develop kidney problems as a result of Lyme disease, they may have signs like vomiting, diarrhea, lack of appetite, weight loss, and increased thirst and urination. Dogs can sometimes have inflammation around the tick bite itself, but lack of a tick bite site doesn’t necessarily mean that a tick bite didn’t occur.
Lyme disease is caused by a bacterium called Borrelia burgdorferi, which is transmitted through a tick bite within 24 to 48 hours. Once inside of the bloodstream, it can spread through connective tissue and to other parts of the body, especially the kidneys, heart, joints, and nerve tissues.
A good medical history can help with diagnosing Lyme disease. For example, a veterinarian may strongly suspect Lyme disease if you and your pet have traveled to an area where there is a large tick population. Lyme disease can sometimes be easily diagnosed via a Snap4Dx test. This blood test looks for antibodies in a dog’s blood sample, and it is a test that many veterinarians keep in their clinics because it can diagnose Lyme disease in minutes. If the test is not available, or if the test is negative but Lyme disease is still strongly suspected, then a blood sample can be submitted to a reference laboratory for a type of DNA test called PCR (polymerase chain reaction). A veterinarian might recommend additional tests to help rule out other illnesses. Tests like a complete blood cell count, blood chemistry, and a urinalysis will help to make sure the patient does not have anemia (low blood cell count) or problems with their internal organs. Veterinarians might also recommend x-rays to make sure that the dog’s bones and joints are healthy.
If Lyme disease is diagnosed, then the veterinarian will treat the patient with an antibiotic for at least four weeks. Doxycycline is one of the most common types of antibiotics for cases of Lyme disease. It helps to treat the infection and also has mild anti-inflammatory properties. Stable patients are usually treated on an outpatient basis and can go home with the antibiotic. However, if kidney disease from a Lyme infection (aka Lyme nephritis) is suspected, then the dog may need to be hospitalized and put on intravenous fluids to help the kidneys. It is also important to note that sometimes antibiotic therapy cannot completely clear an infection, i.e. clinical signs can improve but then might return at a later date. Also, dogs that have had Lyme disease infection once can be bitten by a different tick and develop the infection again 3.
Because Lyme disease can cause pain and anxiety, veterinarians can rely on several therapies to help their patients. Non-steroidal anti-inflammatory drugs, or NSAIDs, can help with pain and swelling. In certain situations, specifically, if there is no response to NSAIDs or if an immune-mediated joint disease is suspected, the veterinarian may consider a glucocorticosteroid like prednisone for treatment. Gabapentin, a medication for neuropathic pain, is also effective in cases of Lyme disease 3. Active research is being conducted on the benefits of CBD oil for dogs, and there is a lot of anecdotal evidence to support the effectiveness of CBD oil for pain and anxiety 4. These effects are reported due to the interaction between the cannabinoids in CBD oil and the endocannabinoid receptors throughout the nervous system.
One of the best ways to prevent your dog from developing Lyme disease is to minimize their exposure to areas with large tick populations. Grassy and wooded areas are the most common places for ticks to hide. If your dog goes on frequent walks through these areas, then it is important to keep them on the designated trails or paths. Topical tick products and tick collars can help repel ticks, and oral tick preventives from your veterinarian are highly effective at killing ticks within just a few hours of exposure. For dogs that live in areas where Lyme disease is endemic, there is a vaccination available that is very effective. The vaccination is also recommended for dogs that have already had a Lyme disease infection because reinfection from another tick bite is always possible. If you find a tick on your dog and the tick is moving around, then remove the tick and place it in a container filled with rubbing alcohol 5. If the tick is attached to your dog, then carefully use tweezers or a special tool called the Tick Twister to remove the tick. Do not pull too quickly or parts of the tick’s mouth could remain under the skin, and do not squeeze the body of the tick because this could squeeze bacteria into the dog’s body.
Lyme disease is a difficult illness that can have lasting effects, and it can be stressful to see your dog in pain. Therefore, it is important to recognize the clinical signs and to have it quickly diagnosed. Be sure to ask your veterinarian for more information on how you can help prevent Lyme disease in your pets.
Dr. Erica Irish
Erica has worked in the veterinary field since 2006, starting out as a veterinary technician before graduating from the UF College of Veterinary Medicine in 2013. As a general practitioner in an animal hospital, she has many interests and is especially interested in dermatology, cardiology, internal and integrative medicine.