Although most feline infectious diseases only affect cats, some of these diseases can be transmitted from cats to people. Diseases that can be transmitted from animals to people are called zoonotic diseases. While not comprehensive, this article highlights the most common zoonotic diseases that may be carried by cats and simple precautions you can take to reduce your risk of contracting these diseases. For more information about specific risks, diagnosis, and treatment of zoonotic diseases, contact your physician/health professional.
WHAT’S THE RISK?
The likelihood of an average person contracting a zoonotic disease from a cat is low, but individuals with immature or weakened immune systems are more susceptible to these diseases. This includes infants, individuals with acquired immunodeficiency syndrome (AIDS), the elderly, and people undergoing cancer chemotherapy or receiving other drugs that may suppress their immune systems.
COMMON FELINE ZOONOTIC DISEASES
Cat scratch disease (CSD) is caused by a bacterium called Bartonella henselae, which may be carried in the saliva of infected cats and in the bodies of cat fleas. As the name implies, this bacterial infection is usually transmitted from cat to human via scratches, although it can also be transmitted via bite wounds and when a cat licks the open wounds of a person. Among cats, this bacterium is most commonly transmitted by the bites of infected cat fleas, and it may also be found in the feces of these fleas, which can serve as sources of infection if exposed to an open wound in either a cat or a human.
People with CSD usually develop swelling and possibly a blister at the site of the bite or scratch. Lymph nodes in the region of the wound may swell and become painful, and affected individuals may experience fever, headache, sore muscles and joints, fatigue, and poor appetite. Healthy adults generally recover with no lasting effects, but it may take several months for the disease to go away completely. People with compromised immune systems may suffer more severe consequences, including infections of the eyes, brain, and heart. Severe cases of CSD may require antibiotic therapy to resolve.
Approximately 40 percent of cats are infected with Bartonella henselae, but most show no signs of disease. Antibiotics do not reliably cure infection in these cats and are not currently recommended. For humans, avoiding scratches and bites (for example, by not allowing children to play roughly with cats), washing hands after playing with cats, controlling fleas, and keeping cats indoors all reduce the risk of CSD. Because most cases of CSD result from contact with kittens under one year of age, immunocompromised people should avoid such contact.
Pasteurella multocida is a bacterium found in the mouths of between 70 and 90 percent of cats, and it has been found in between 50 and 80 percent of cat bites in humans that become serious enough to seek medical attention. Cat bites infected with this organism may develop pain, swelling, and redness at the wound site within 24 to 48 hours. Pasteurella-infected cat bite wounds are successfully treated with antibiotic therapy in the vast majority of cases, but more serious complications, such as the spread of bacteria through the blood stream and infection of heart valves, may occur in rare cases.
Salmonella poisoning, also called salmonellosis, is caused by a group of bacteria called Salmonella, and can lead to diarrhea, fever, and stomach pain beginning one to three days after infection. People usually contract salmonellosis by eating contaminated food, such as undercooked chicken or eggs, but it is possible to contract the disease from infected cats, which can carry Salmonella bacteria and pass them in their stool. Although salmonellosis usually resolves on its own, some individuals require medical attention to address severe diarrhea or the effects of the infection on organs other than the digestive tract.
Salmonella is more commonly found in cats that feed on raw meat or wild birds and animals, so owners can reduce the risk of salmonellosis in themselves and their cats by keeping cats indoors and feeding them cooked or commercially processed food. Wearing gloves when cleaning litterboxes or gardening (in case outdoor cats have defecated in the soil) and washing hands thoroughly after these activities is also recommended.
…continued in Part 2 this evening…