Disease

September 2019 Issue




Cats Are Resistant to Lyme Disease

Misinformation abounds about why, however

Bork | Deposit photos

Tick prevention remains important in cats, outdoors and indoors.

Q. Recently, my dog was diagnosed with Lyme disease. When I asked my vet about checking my cats, he said that cats did not get Lyme because of how they groom themselves. I have read several accounts of pet parents looking for help because their cat contracted Lyme. Can you please clear up this quandary and list symptoms?

A. Thanks for getting in touch about this important disease that appears to be increasing in frequency in both people and dogs. This is largely due to climate change that has increased the range of the ticks that transmit it, the growth of deer populations, and increased exposure of people and dogs to ticks as land development progresses.

Lyme disease, caused by infection by the bacteria Borrelia burgdorferi, is the most commonly diagnosed vector-borne disease in people in the United States, and it is probably true that numbers of infections are higher than are verified (many cases go unreported).

Lyme disease usually affects the joints, kidneys, heart and, in rare cases, the central nervous system in people and dogs that are infected if they are not appropriately treated. Signs of Lyme disease in dogs include lameness, lethargy, loss of appetite, weakness, increased or decreased urine production, and swelling of the joints.

For reasons that are not clear, there is no evidence that infection with Borellia burgdorferi causes disease in cats. While there has been speculation that this may be due to cats’ fastidious grooming and rapid removal of ticks before they can transmit the disease, cats have been shown to produce antibodies to the bacteria that causes Lyme disease in both experimental and real-world situations, and yet these cats do not appear to develop disease. This finding suggests that cats’ resistance to Lyme disease is not due to their rapid removal of ticks, as the development of antibodies against B. burgdorferi suggests that cats do become infected (i.e. their immune system is exposed to the bacteria), but for some unknown reason, they do not seem to develop any ill-effects of this infection.

Although cats do not seem to be negatively affected by B. burgdorferi infection, there are significant and potentially fatal diseases that can be transmitted to cats by ticks. Among these are hemobartonellosis (aka feline infectious anemia), tularemia, babesiosis, and cytauxzoonosis. The first two are caused by bacterial infections, and the latter by protozoal infections. Appropriate diagnosis, treatment, and supportive care are necessary for the most favorable outcomes.

Cats are unique in so many ways, and their resistance to Lyme disease is another of these distinctive characteristics of our feline friends. As you can see, though, there is still enough concern for tick-borne diseases in cats to recommend that owners pay careful attention to tick prevention in cats. There are effective tick preventatives. A discussion with your veterinarian is the best way to decide what is best for you.

I hope this is helpful. If we become aware of any research that suggests that cats may, in fact, be susceptible to Lyme disease, we will most certainly make this known to our readers.

All my best,

Elizabeth