Here’s a question for you “owners” of outdoor cats: How often have you opened your door to leave your house, only to be surprised with a dead mouse or other small creature waiting for you on the step?
This was not uncommon at my previous house, where our cat Josephine had a big pasture where she honed her hunting skills. Every so often she would leave us this kind of “love offering,” sometimes accompanied by her proud-looking presence.
Josephine’s offerings were a manifestation of her maternal instincts. If she had youngsters of her own, she would bring them these captured critters so they could practice their hunting techniques. Because I had surgically removed any possibility of her having a feline family of her own, her human family was her substitute.
These “deposits” could be a bit unappealing but generally not problematic health-wise. However, feline hunters have the potential to bring you something less obvious and more consequential than a dead mouse – tularemia.
Tularemia is a disease caused by a bacteria called Francisella tularensis. Of all the different species that can contract tularemia, cats seem to be especially susceptible. They pick it up from the animals they prey upon outdoors. In particular, cottontail rabbits are very common sources – “reservoirs” – of tularemia in nature. Additionally, in the wild as well as in the backyard, ticks can spread the bacteria among rabbits and other animals, including cats and people.
Cats infected with tularemia can show anything from mild signs of illness to a fatal, whole body infection. Severely affected cats will be feverish, lose interest in eating and become dehydrated and lethargic. They may have swollen glands in the neck or draining sores. Once severe signs set in, the infection is very difficult to successfully treat. (These same signs affect diseased wild rabbits and rodents, making them easy prey for the cats). Dogs seem to be more resistant to tularemia, but illness is possible in them too.
While this disease is bad news for cats and rabbits, tularemia can also cause illness in people too. People contract tularemia through tick bites or contact with sick animals, such as the cats mentioned above. Cat to human transmission usually happens through scratches and bites, but sometimes the route of entry of the bacteria is not known.
One of the remarkable aspects of tularemia is that exposure to just a few bacteria can cause illness. In people, tularemia most commonly shows up as the “ulceroglandular” form. A sore develops at the point of entry (either the tick bite or the cat scratch/bite), along with fever and swollen lymph nodes in the area. Untreated, these infections can spread throughout the body and persist.
Human tularemia infections are reported every year in South Dakota. Human and animal cases pop up in every area of the state, but for animal cases that come through the SDSU veterinary diagnostic lab, central South Dakota seems to be more well-represented than elsewhere.
Unfortunately, there is no preventive vaccine for tularemia, either in cats or people. The best prevention begins with an awareness of the disease and using that knowledge to protect ourselves and our animals.
First off is tick prevention. There are now many good products that can do this for our pets — however, it’s critical to know that many tick-repellent preparations for dogs are toxic to cats. Always check with your veterinarian before using a new product, or better yet, obtain it directly from them. Take precautions yourself when you’re out in potentially tick-infested areas.
Secondly, watch your outdoor cats closely for any signs of illness. Seek veterinary care or advice when unexpected signs of illness show up. When working with potentially sick animals, take care to protect yourself from any scratches or bites that a poorly-feeling animal might deliver.
Thankfully, cases of tularemia are still relatively uncommon. However, when they do occur, those illnesses can be quite debilitating – for animals as well as people. Being aware that tularemia can be in our midst is a good first step to making sure you or your animals don’t become one of those cases.
Russ Daly, DVM, is the Extension Veterinarian at South Dakota State University. He can be reached via e-mail at firstname.lastname@example.org or at 605-688-5171.