Lyme disease is tick-borne and affects both humans and animals. The causative organism is a spiral shaped bacteria called Borrelia burgdorferi. While it has been reported across the United States, it is more common in the Northeastern states. The most common sign of Lyme disease is polyarthritis (arthritis in more than one joint). Other signs that may be seen are fever, loss of appetite, and lethargy. Despite the uncommon occurrence of the disease in dogs and humans, the importance is the damage that it causes during the infection. The joint damage from the disease can be irreversible if not treated, leaving the affected individual disabled for life. Human cases tend to be more severe than canine with additional signs of meningitis, myocarditis, and uveitis (inflammation of the eye) along with the arthritis.
The bacteria are spread through the bite of an infected tick, which gets infected by ingesting the organism from an infected host (mice, dogs, humans, etc.). If the tick detaches from the first host and reattaches to a new one, it can give the lyme disease organism to the new host. Mice are a common reservoir of the disease infecting the larval ticks before they move on to larger hosts like dogs and humans. Infection occurs in dogs regularly exposed to tick populations, but clinical disease is not always evident.
Diagnosis is accomplished through blood tests for antibodies. Exposed animals that may not currently show any signs of the disease can test “positive” on antibody screening tests. This positive response can last for many years. Thus precise diagnosis can be difficult to achieve. A combination of test results and clinical signs give the veterinarian the evidence needed to confirm a case of active infection. Along with antibody testing, joint fluid analysis and general blood tests may be needed.
Treatment consists of long-term (three weeks or longer) use of antibiotics. Although antibiotics will relieve the symptoms of the infection in most affected animals, they will not get rid of the organism in the body. Because this organism is not removed from the body, symptoms can re-occur at any time and antibody titers will not necessarily decrease post treatment.
The best way to prevent infection is to control the transmitting vector, the tick. Check pets regularly for ticks and remove any found. Since transmission requires that the tick be attached for longer than 48 hours, it is important to remove any ticks as soon as they are found. Use topical (spot on, dip, spray, collar) and environmental (yard) control products as directed by your veterinarian. A vaccine is available, but is only recommended for those dogs at high risk – field trial, hunting dogs, etc. The vaccine can cause some screening tests to be “positive” making interpretation difficult.
For more information contact: Dr. Wanda Pool, Deepwood Veterinary Clinic 703-631-9133