Lyme Disease and Pets
Lyme disease is not only a threat to humans, but manifests in dogs and, to a lesser extent, in horses, cattle, and cats, while many wildlife mammals and birds become subclinically infected and serve as reservoirs for tick infection.
What are the signs of Lyme disase in dogs?
In contrast to human cases of Lyme disease, where three different stages are well known, Lyme disease in dogs is primarily and acute or subacute arthritis. The acute form may be transient and may recur in some cases. The devastating chronic stage in humans with systemic disease has rarely been seen in dogs.
Dogs show sudden lameness and sometimes signs of severe pain. One or more joints may be involved. Joints are often swollen, hot, and painful upon manipulation. Dogs may have fever and be off-feed and lethargic. Some become severely depressed and are reluctant to move. Lameness may recur after a period of recovery lasting several weeks.
Lameness in dogs occurs an average of two to five months after tick exposure.
The first stage of human Lyme disease, a skin rash called erythema chronica migrans, is rarely seen in dogs. Some symptoms associated with the later stages of Lyme disease in humans have also been reported in rare instances in dogs. They include heart block, kidney failure, and neurological changes such as seizures, aggression, and other behavior changes.
What is the likelihood of a dog will contract Lyme disease?
The proportion of infected dogs that develop clinical disease is far smaller than it is for humans. Serological studies suggest that while more than 75 percent of the dog population in hyper-endemic areas may be exposed to infected ticks, only about five percent of those exposed actually develop clinical signs that might be attributable to Lyme disease. Within endemic areas, “hot spots” of tick infestation where dogs have a much greater probability of acquiring an infection are intermingled with non-infested areas where the habitat is not favorable to the vector tick. There may be age, breed, and genetic differences in the susceptibility of dogs to Lyme disease, but little is known yet about these factors.
Information sourced from the Baker Institute for Animal Health at Cornell University's College of Veterinary Medicine.