Lyme disease is a very common tick-transmitted disease that was first recognized in 1975. It was first seen in a large number of people around a small town from which it was named, Lyme, Connecticut. It is caused by a bacterial spirochete species of the Borrelia burgdorferi family. It wasn’t until 1981 that the disease was connected to the ticks that transmit it, Ixodes sp., commonly known as the deer tick. There are two species which predominate, Ixodes scapularis, the black-legged tick found primarily along the east coast and the Midwest and Ixodes pacificus, the western black-legged tick which is found along the west coast of the United States. Ticks can be seen in every season, but most activity is between October and March and yes, they can overwinter as cold weather does not kill them but only inactivates them until the temperature goes high enough for them to become active again. Lyme disease can be found in dogs, cats, horses, cattle and wildlife such as white-tailed deer, mice, chipmunks, squirrels, opossums and raccoons and as most are aware in people.
Transmission of Lyme Disease
As stated above, Lyme disease is transmitted by the deer tick. It is not passed directly from one animal to another but via the bite and subsequent transference of the spirochete to the host animal upon which the tick is feeding. The tick must be attached for 24-48 hours for this disease transmission to occur. Some scientists feel that at least 50% of the deer ticks may be infected with the disease. Obviously our pets may come into contact with these ticks in wooded, bushy areas and forests in which we go camping or hunting. The risk of infection is highest in the spring with the nymph stage of the tick’s life cycle as these are only about as big as a period at the end of a sentence (very hard to see except maybe on a cat’s ears where I have found several). The adults may transmit the disease in the spring or fall but are more easily seen and removed before the disease can be transmitted to the host animal.
Signs of Lyme Disease
Initial infection with Lyme disease is often overlooked in our animals as it is very subtle and ignored as it usually doesn’t last very long. These initial signs are fever, mild loss of appetite, decreased energy ( I see a lot of this in the hunting dogs). Chronic (2-5 months after initial infection) disease is more commonly seen and includes signs of generalized stiffness, shifting leg lameness, intermittent lameness, swelling of the joints and less commonly facial paralysis, seizures, heart and kidney problems. Kidney disease is thought by some to be the second most common sign after lameness and generally causes the affected animal to die. Some “experts” say that only 5-10 % of infected dogs show any signs which has led to the new controversy of whether or not to treat the positive dog that is not showing signs of disease. I do see a lot of positive dogs in my area that are not showing signs, but I feel this is because many people are so aware of the problem that they seek help as soon as they pick ticks off of their dog. I also believe in treating in the absence of signs as I don’t feel like one should wait for the disease to progress to the point of major problems. I had a young beagle that developed the kidney problems and died within 6 months of diagnosis and being treated.
Diagnosis of Lyme Disease
Initially, it was very hard to detect this disease and therefore, serious and often life-threatening health problems were seen. Today, we have several ways to detect the disease. The most common is an Enzyme Linked Immuno Assay (ELISA) test and a Western Blot test. The ELISA can be done in clinic and takes less than 20 minutes to run with just a few drops of whole blood. False negatives can occur by testing too early in the course of the disease (usually takes at least 3 weeks after a tick bite to get an antibody response within the body that can be detected by the test) and a chronic disease state may no longer have antibodies within the bloodstream as it may concentrate only in affected joints.
Treatment of Lyme Disease
After a positive test, treatment is usually started immediately. Either Doxycycline or Amoxicillin is prescribed for 4-6 weeks. Some people advocate also vaccinating with the Lyme disease vaccine. There is controversy as I stated earlier with treatments. In my clinic, I use the Lyme disease vaccine and initiate Doxycycline treatment for 4 weeks. I retest in 90 days and have so far had two that have been negative at retest using this protocol. Those still testing positive and not having problems, we simply watch and initiate another 4 weeks of treatment with any notice of problem signs. A clinician at The Ohio State University informed me that some may never become negative on retest mainly depending on each individual animal’s immune system and response to treatments.
Prevention of Lyme Disease
If we can prevent infection of any kind, of course, it is in the best interest of the animal’s health as well as our pocketbook. Therefore, vaccinating for Lyme disease initially (I have had a 4-month-old beagle pup test positive but was one of my success stories of becoming negative after treatment!) is important as is keeping the ticks off of our animals. Pups can be vaccinated as early as 12 weeks of age and need a booster in 2-3 weeks with annual revaccination recommended. Tick avoidance is easy with our small house dogs and cats, but not so much for our farm and hunting dogs or horses that are exposed on an almost daily basis to areas and wild animals that may be harboring these ticks. Because of these exposures, it is important to have some type of tick treatment or prevention on our pets. There is really no “one size fits all” approach when it comes to tick prevention. Some feel the Seresto collars are best as they both kill and repel ticks for up to 8 months and they don’t have to attach and bite the host animal to be killed. These may not work on some breeds, or if in a multi-animal environment, they may remove them from each other and a pet that swims in your pond or creek out back frequently is not likely to get a full 8 months of protection. There are many topical products (Frontline and Advantix) that work well for some and also oral tablets (Nexgard, Bravecto, Simparica and Credelio) that some prefer. If our pets cannot be kept away from possible tick infested areas, it is best to use some type of tick treatment and check them frequently to make sure your treatment is working. This is one disease where I feel that Benjamin Franklin’s old saying definitely applies: “An ounce of prevention is worth a pound of cure.”