Lyme disease is an illness caused by a microscopic bacterium that is spread by ticks. In many areas of the country, it is becoming more and more common. For example, in central Ohio where I practice veterinary medicine, I see more dogs that are Lyme positive than I do that are positive for heartworm disease. The risk in my county is 10 times higher than it was just 10 years ago.
Lyme disease can cause severe debilitating arthritis and organ failure that can be fatal. The risk of disease is dependent upon exposure to infected ticks. Clients commonly ask about the risk of Lyme disease in their dogs. Some knowledge and simple precautions can help prevent Lyme disease.
Lyme disease was discovered in Lyme, Connecticut in 1975. Since its discovery, it has been known to affect humans, dogs, cats, and horses. Dogs and cats cannot transmit the disease to humans. Lyme disease in people has been reported in North America, Europe, and Asia. Ticks infected with Lyme disease are commonly found in the Northeast, Southeast, Pacific Northwest, and upper Midwest regions of the United States.
Lyme disease works like this: The bacterium that causes Lyme disease, Borrelia burgdorferi, lives in small mammals such as mice. Ticks commonly feed on the small mammals and become infected with Borrelia burgdorferi. The common tick involved is the deer tick (primarily the species Ixodes including I. scapularis and I. pacificus). Deer support the deer tick but are not thought to be infected by the organism.
The tick then bites and attaches to a dog or human. It is generally thought that the tick needs to be attached for 2 days before the transmission of the organism is accomplished. Not all pets that are bitten by an infected tick are at risk for developing the disease. In fact, it is estimated that less than 5% of dogs exposed to Lyme disease develop signs of illness. The other 95% of dogs exposed to the bacterium that don't develop signs of disease will still have a positive blood test.
Signs of Lyme Disease in Dogs
The most typical symptoms of Lyme disease are lameness and joint pain. These may be the only signs in some pets. The lameness can present suddenly or be chronic and progressive. It can also shift from one leg to another leg. Other signs may include lack of appetite, lethargy, weight loss, fever, and lymph node enlargement.
Symptoms generally develop 2 to 5 months after tick exposure. Progressive and chronic injury can occur to the joints and kidneys causing irreversible changes.
Diagnosis of Lyme Disease in Dogs
The diagnosis is often made based on the pet's symptoms, history of tick exposure in an area where Lyme disease is found, and blood testing. However, the diagnosis of Lyme disease using the blood test can be difficult because of the prevalence of dogs with antibodies to Borrelia is much more common than the clinical disease.
Treatment & Prevention of Lyme Disease in Dogs
Lyme disease is treated with antibiotics. Treatment is most effective when diagnosed early and begun before irreversible changes occur to the body.
Lyme disease most commonly affects outdoor dogs that are exposed to infected ticks. Prevention of Lyme disease focuses around the avoidance of ticks and vaccination. Prevention of ticks can be accomplished by using tick prevention collars and medications and by checking your dog daily for ticks.
As mentioned above, ticks need to be attached for 2 days before they can become infected, so daily checking is a great preventative tip!
There is a commercially available vaccination against Lyme disease that is recommended for dogs with a high risk of tick exposure or that travel to Lyme endemic areas. Discuss vaccine recommendations with your veterinarian. Recommendations should be based on your dog's potential tick exposure and the presence of Lyme disease in your area.
The CDC frequently maintains a log of information about disease prevalence and maintains it on their site. For information about prevalence in your area, go to Risk Maps for Lyme Disease. This link is also a very good one from the CDC that has updated information about Lyme Disease in Humans.
Find out the Risk of Lyme in Dogs in Your County
An interesting website that tracks the incidence of Lyme disease in the United States is www.capcvet.org. Go to the Parasite prevalence maps on the top navigation bar then see where it defaults to heartworm disease. Click “Tick-Borne Disease Agents”. You can further refine your search by “Lyme Disease” and “Dogs”. Next, click on your state and your county. You can also refine this search by year. You can easily compare stats year over year.
IMPORTANT: *These numbers reflect the total number of tests reported to CAPC in this defined area and represents a sample of the total dog/cat population in this area. The data is provided by IDEXX Laboratories and ANTECH Diagnostics. It is estimated these numbers represent less than 30% of the activity in the geographic regions.
I hope this article gives you more information about if your dog is at risk for Lyme disease.