Stray cats can carry a variety of diseases that can be transmitted to humans. Some of the most common and concerning diseases that stray cats may harbor include rabies, cat scratch disease, toxoplasmosis, campylobacteriosis, and ringworm. While the risk of disease transmission from stray cats varies based on the pathogen, there are important prevention measures that can be taken to reduce the chances of infection.
Rabies
Rabies is a deadly viral disease that affects the central nervous system. It is spread through the saliva of infected animals and is transmitted through bites or scratches. In the United States, rabies is most commonly found in wild animals like raccoons, skunks, foxes, and bats. However, stray cats can also contract rabies from these wild animals and potentially spread it to humans.
According to the Centers for Disease Control and Prevention (CDC), stray cats are the most common domestic animal to test positive for rabies in the U.S. Cats with rabies tend to exhibit signs like aggression, difficulty swallowing, paralysis, and seizures. However, rabid cats can also appear healthy in the early stages of infection and transmit the virus before showing symptoms.
Rabies has a nearly 100% fatality rate if post-exposure prophylaxis is not administered promptly after a bite or scratch from a rabid animal. This involves receiving a dose of rabies vaccine and rabies immunoglobulin within the first few days after exposure. Preventing contact with stray cats and other unknown animals is key to avoiding potential rabies exposure.
Cat Scratch Disease
Cat scratch disease (CSD) is an infection caused by a bacterium called Bartonella henselae. As the name suggests, it is usually transmitted through a bite or scratch from an infected cat. Kittens under the age of one year are the most likely to harbor and spread B. henselae.
Within 3-14 days after a cat scratch, symptoms of CSD may appear including fever, headache, poor appetite, and exhaustion. A bump or blister typically forms at the initial scratch site. Swollen lymph nodes near the scratch are also common. In more serious cases, CSD can affect the brain, eyes, heart, or other organs such as the liver and spleen.
There were over 12,000 hospitalizations due to CSD in the U.S. between 2000 and 2010. The disease does usually resolve on its own after a few months, but antibiotics can be used to treat severe cases. Avoiding scratches and bites from stray cats is advised, especially for people with weakened immune systems who are more prone to complications.
Toxoplasmosis
Toxoplasmosis is caused by the parasite Toxoplasma gondii. Cats are the definitive host for T. gondii, meaning the parasite reproduces in the cat intestinal tract and spreads through their feces. Humans can contract toxoplasmosis by accidentally ingesting contaminated soil or water.
According to the CDC, more than 40 million people in the U.S. may be infected with toxoplasmosis. But very few people ever experience symptoms because a healthy immune system keeps the parasite from causing illness.
For those with compromised immunity, toxoplasmosis can lead to flu-like symptoms, blurred vision, and in severe cases, lung, heart or brain problems. Congenital toxoplasmosis acquired by a mother during pregnancy can also seriously affect the fetus.
Stray cats that use gardens, sandboxes, or other areas that people frequent are more likely to increase local environmental contamination with T. gondii. Washing hands before eating, washing fruits and vegetables, and not drinking untreated water from streams or reservoirs can help reduce toxoplasmosis infection risks.
Campylobacteriosis
Campylobacter bacteria are a common cause of gastrointestinal illness in humans. Most cases of campylobacteriosis are caused by C. jejuni found in animal feces. Consuming undercooked meat or contaminated food/water, or direct contact with animal feces are the primary routes of transmission.
According to the CDC, cats and dogs with campylobacter do not normally show illness but can shed the bacteria in feces for months after infection. One study found that nearly 50% of stray cats assessed were shedding pathogenic Campylobacter bacteria.
Symptoms of campylobacteriosis usually appear 2-5 days after exposure. Diarrhea (sometimes bloody), fever, and stomach cramps are common. The infection generally lasts around a week but can be serious and require hospitalization in those with compromised immunity.
Avoiding fecal matter from stray animals and thoroughly cooking meats can help prevent campylobacter infections. Proper food handling and hand hygiene after interacting with animals are also important preventive measures.
Ringworm
Ringworm is not actually a worm, but a contagious fungal infection that can be spread between cats, humans, and other mammals. Stray kittens and cats that are immunocompromised have an increased risk of harboring ringworm. The medical name for ringworm is “tinea.”
There are a few different types of ringworm such as:
- Tinea corporis – causes ring-shaped rashes on the body
- Tinea capitis – leads to scalp lesions and hair loss
- Tinea pedis – infects the feet as “athlete’s foot”
Ringworm thrives in moist environments and is easily transmitted through contact with contaminated fur or skin lesions. Spores can also spread on surfaces or soil and infect those who touch the area.
Within 4-14 days after exposure, ringworm causes itchy, scaly patches that may blister or ooze. Oral antifungal medications can treat the infection within about a month. Keeping skin clean and dry prevents fungus growth.
Preventing Zoonotic Diseases from Stray Cats
Zoonotic diseases that stray cats can transmit are best prevented by limiting interaction and avoiding bites/scratches. Other tips include:
- Do not feed or touch stray cats since they can still pose a disease risk even if they appear healthy.
- Spay/neuter owned cats to prevent unwanted litters that contribute to stray populations.
- Talk to children about the risks of approaching unknown animals.
- Clean and cover any wounds from animal encounters thoroughly.
- Avoid stray cat feces in outdoor areas like gardens where food is grown.
- Wear gloves when gardening or handling soil where strays frequent.
- Do not allow pets to come into contact with strays.
In many areas, there are trap-neuter-return (TNR) programs available to humanely reduce local stray cat colonies while also controlling the spread of disease. TNR involves trapping stray cats, spaying/neutering and vaccinating them against rabies, and then returning them to their outdoor environment once recovered.
Stray cats serve as an environmental reservoir for various bacteria, parasites, and viruses that can infect humans in certain situations. But the risk of transmission can be significantly decreased by following prevention measures and avoiding direct contact with unknown stray cats roaming outdoors.
Conclusion
Stray cats can potentially carry concerning diseases like rabies, toxoplasmosis, campylobacteriosis, cat scratch disease, and ringworm. These can be transmitted to humans through bites and scratches or contact with contaminated feces. However, the risk of infection is fairly low for indoor-only cats and humans who take proper precautions.
Avoiding direct contact with strays, practicing good hygiene, promptly cleaning wounds, and preventing the proliferation of stray colonies in residential areas can substantially reduce the likelihood of disease transmission. Understanding the main zoonotic diseases stray cats can harbor helps individuals take steps to protect their health.