Lyme disease is the most common tick-borne disease in dogs and people in the United States. It is caused by a bacteria called Borelia Burgdorferi and is transmitted through the bite of an infected tick. Many species of mammals are susceptible to infection. In companion animals, dogs and horses seem to be the most likely to develop clinical signs from Lyme disease, while cats seem to be naturally resistant to infection. Lyme is most prevalent along the east coast and Great Lakes regions of the United States, but is found in many other areas of the country as well.
While Borelia Burgdorferi can infect multiple species of tick, only the black-legged tick (also known as the deer tick) and the Western black-legged tick have been shown to transmit the disease to other hosts. Transmission occurs 24-48 hours after a tick attaches to its host. Ticks find and bite a host and attach by embedding a feeding tube into the host’s skin. The tick then secretes a small amount of saliva through the feeding tube which anesthetizes the skin and prevents the host from detecting the tick. As the tick feeds, it continues to secrete saliva into the wound. 24-48 hours after feeding begins, the Lyme bacteria mobilizes and enters the host through this saliva secretion.
Most dogs who become infected with the Borelia Burgdorferi bacteria do not develop clinical signs of Lyme disease. Instead, they are infected subclinically, meaning they carry the bacteria but do not get sick from it. Dogs that do develop clinical signs of Lyme are likely to exhibit a combination of fever, lameness and general malaise. Less commonly, the Lyme bacteria can infect the kidneys, causing significant protein loss through the kidneys which eventually leads to kidney failure. In very rare cases, Lyme disease can cause heart or brain disease.
Lyme disease is treated with antibiotics and supportive care. Although antibiotic treatment is often successful in resolving clinical signs of disease, low-levels of bacteria generally remain in the body and infected patients may continue to test positive for Lyme infection long-term. Persistently infected dogs may have a recurrence of clinical signs during times of stress or immunosuppression (for example, during cancer treatment or treatment of autoimmune disease).
The best way to protect your pet is to prevent Lyme disease transmission in the first place. Tick control is the first line of prevention. Keep your pet on a high-quality tick preventative year-round to limit his exposure. Secondly, a Lyme vaccine is available to help your dog fight of the Lyme bacteria if he is bitten by a tick. This vaccine is given annually after the initial two-booster series. Finally, your veterinarian may recommend antibiotic treatment after a recent tick bite to try and kill any transmitted bacteria before they can establish an infection in your pet.
Caring Hands Animal Hospital recommends annual testing of dogs for Lyme disease using our in-house Heartworm/Lyme/Ehrlichia/Anaplasmosis test. This test is the most accurate way to screen for Lyme infection. If the dog tests positive, your veterinarian may recommend additional testing and/or a course of antibiotics. Dogs who have tested positive in the past should be tested using a send-off test called the Lyme C6. This test measures the amount of Lyme antibody in the dog’s body and is an accurate way to measure the number of Borelia Burgdorferi bacteria present. If this number is rising, re-treatment with an antibiotic may be needed.
Lyme disease affects people as well as animals. Although the disease is not transmitted directly from animals to people, people can be infected by the bite of an infected tick. At the current time, there is not an effective Lyme vaccine available for people. Thus, tick prevention is the best method of preventing Lyme disease in people.
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