Lyme disease is one of the most common tick-borne diseases in the world. It most often affects humans and dogs, but in rare cases it has been reported in horses, cattle and even cats. It has been documented worldwide and in the United States, the majority of cases have been in the northeast. Lyme disease is caused by a spirochete bacteria, Borrelia burgdorferi, that is transmitted by the deer tick, Ixodes scapularis. The deer tick has a 2-year life cycle that involves being carried by white-footed mice, deer and other mammals. Infection occurs when a dog or human is bitten by a tick harboring the bacteria. If the tick remains attached and takes a blood meal for 24 to 48 hours, the spirochete bacteria is transmitted and infection results.
What are the symptoms?
The common clinical signs of Lyme disease in our canine companions includes acute lameness in one or multiple limbs, stiffness and an arched spine. Fever, loss of appetite and depression are also common. In rare situations heart and neurological abnormalities may take place. The kidneys may also be affected, resulting in a condition referred to as Lyme nephritis, which carries a grave prognosis and is invariably fatal. Though Lyme nephritis is also rare, Labrador Retrievers seem to be more susceptible to this manifestation of the disease. The chronic arthritis that often affects humans with Lyme disease does not seem to take place in dogs.
How is it diagnosed?
Testing dogs for Lyme disease involves a blood test that confirms exposure to ticks carrying the bacteria. Traditionally these tests were performed by outside laboratories, but recently an in-hospital and less expensive test has become available for your veterinarian to perform.
How is it treated?
Treatment involves an extended course of antibiotics to hopefully rid the dog of the bacteria and anti-inflammatories for pain relief if needed. Most dogs respond well to treatment if started early enough in the course of the disease, but in some cases, chronic recurrences have been seen.
How is it prevented?
Prevention of Lyme disease is multi-faceted. All dogs in Maryland are exposed to ticks, even if they are just in your yard or out and about in the neighborhood. Tick control techniques have improved dramatically over the past decade with the development of topically applied veterinary licensed and dispensed small volume liquid products, such as Frontline Topspot, which has the added benefit of killing fleas. Overall, these veterinary products are very safe to apply to your dog and cat and are very effective in killing ticks that may bite them. Closely examining your dog and cat’s coats and frequent grooming may help find ticks. However, the deer tick is extremely small and easily unobserved. Canine vaccines to prevent Lyme disease have also been developed and proven to be safe and effective when given annually after an initial series of booster vaccines. However, tick control is still very important, even when your dog is vaccinated against Lyme disease. Other tick-borne diseases, such as Rocky Mountain Spotted Fever and Ehrlichiosis may still be transmitted to your dog through tick bites. While ticks will not infest your house like fleas, they may be brought in and carried onto you and other family members.
What is the prognosis?
The prognosis for dogs with Lyme disease is generally good, provided they are treated with an appropriate course of antibiotics and they do not have the kidney manifestation of the disease.