Zoonosis (transmission of disease from animal to human) is a significant risk to the health of people throughout the world. It can potentially occur directly through immediate contact with an animal or indirectly through excretions (stool, urine, saliva, blood, etc), fomites (sputum, hair, etc that has been left in the environment), and vectors (another insect or animal that acquires the infection and transmits it to a human) such as fleas and mosquitoes. These infections tend to be more severe in children, senior citizens, and immunocompromised individuals. In our local cat population, there are a few important zoonoses.
Tapeworms, Roundworms, Hookworms – Ingestion of the infective stage (egg or larva) in the stool or water is required for infection of most intestinal worm parasites. Various impacts on health can occur depending on the parasite and health status of the individual affected. The most common significant risk from intestinal parasites is worm migration, as seen with several types of roundworms. These worms can move throughout the body, causing damage where they travel and can be life-threatening. A dangerous tapeworm, echinococcus, is rare but occurs more commonly in cats that are allowed to hunt. Hookworm larva can penetrate directly through the skin, causing a very itchy skin rash.
Protozoans – Spread through the stool, these organisms require ingestion of the infective stage to become infected. Toxoplasmsa gondii is one of the most well-known agents in this group due to the risk posed to the fetus of pregnant women. Giardia is very familiar to many people as well, due to the severe diarrhea that is produced. Giardia is very common in Austin, but there is evidence that human infection probably occurs more often from human-to-human contact or from a contaminated environment (streams and greenbelts) than from one’s own infected cat. Cryptosporidium can also cause severe diarrhea.
Gastrointestinal Bacteria –
Salmonella – species, E. coli, Helicobacter, Yersenia enterocolitica, Campylobacter are all transmissible to people through contact with infected feces or vomit. These bacteria most commonly cause gastrointestinal infections that can be very severe.
Flea-associated bacteria –
Bartonella species – This bacteria is present in the feces of fleas. If a cat is infested with fleas and bites or scratches a person, they are at risk for infection. Commonly known as “Cat Scratch Fever,” a skin infection can lead to systemic illness affecting many organs and the effects can last a long time.
Yersenia Pestis – Cats generally get infected with the organism known for causing “The Plague” after ingesting a rodent with yersenia-infected fleas. People can become infected from a bite by an infected flea and/or contact with respiratory, oral, or skin secretions from an infected cat. This disease is rare and can be prevented through flea control and keeping cats indoors.
Bite-wound associated bacteria –
Capnocytophaga, Mycoplasma felis, and Pasteurella species – Reports indicate that 80% of cat bite wounds (humans bitten by a cat) get infected. The majority of the time, the infection is limited to the skin and, with appropriate treatment, resolves. However, some bacteria (listed above) are more prone to causing more severe infections, which can become life-threatening if appropriate treatment with a physician is not pursued.
Rabies – This virus is transmitted through the saliva or neural tissues of an infected animal. Any mammal can be infected. A person does not have to be bitten to get infected as any break in the skin (example hangnail) could allow penetration of virus into the body. Once a person is infected, the disease is fatal if prompt treatment at a hospital with a series of injections is not pursued. At this time, testing your cat for rabies is not possible while your cat is living. A lab must analyze the brain to determine if a pet contracted rabies. Routine vaccination with your veterinarian is extremely effective in preventing rabies.
Ringworm – is a fungus that lives within the hair follicles and skin of infected cats and other animals. Direct contact or contact with shed hairs can lead to the skin infection in people. This infection can be treated in pets and people.
Sporothrix schenkii/ Sporotrichosis – This fungus is present in soils around the world. Infections can occur through any break in the skin that allows a spore to enter (in cats and in people). Draining skin lesions in the cat can infect a person.
While there are many diseases that can be transmitted from cats to humans, there are a few simple steps that can be taken to dramatically reduce the risk.
1. Quarantine new cats entering the home from any immunocompromised people until risk assessment has been determined by a veterinarian.
2. Wash hands after handling cats and especially after touching a litter box.
3. Cover sandboxes when not in use.
4. Prevent children from eating dirt, drinking water outside, or mouthing objects outside as much as possible.
5. Vaccinate for rabies yearly.
6. Use monthly flea and tick prevention.
7. Keep your cat indoors. Deworm regularly if your cat goes outside.
8. Do not allow your cat to lick your face, utensils, etc.
9. Clip the nails frequently, especially if your cat is prone to scratching.
10. Do not touch stray or unfamiliar cats.
11. If bitten or scratched by a cat, seek medical attention.
12. Seek veterinary care once to twice yearly for a physical and fecal exam.
13. Do not handle unhealthy cats. Wear gloves if your own cat is ill and requires handling.
14. Use litter box liners and/or disinfect the litter box periodically.
15. Control flies and cockroaches as much as possible as these can transport infectious agents from the litter box to other locations in the home.
16. Only feed cats cooked diets.
17. Do not let cats drink from the toilet.
18. Do not allow your cat to hunt.