Watch Out! These 5 Dangerous Diseases Your Cat Could Be Spreading to You


Zoonotic diseases are illnesses that can be transmitted between animals and humans. Cats can carry and transmit several zoonotic diseases to their owners through bites, scratches, contact with saliva, feces, or urine, fleas, ticks, or simply through close contact. Some of the most common feline zoonotic diseases include toxoplasmosis, cat scratch disease, rabies, ringworm, tapeworm, campylobacteriosis, salmonellosis, and leptospirosis.

While the risk of contracting a disease from a cat is generally low, immunocompromised individuals, pregnant women, young children, and the elderly are at higher risk for developing more severe symptoms. Practicing good hygiene, keeping cats indoors, controlling fleas and ticks, and regular veterinary care can help reduce the chances of disease transmission between cats and humans.


Toxoplasmosis is caused by the Toxoplasma gondii parasite. This parasite is found in cat feces and spreads to humans through contact with infected feces. Up to 60 million people in the United States may be infected with the Toxoplasma parasite (

Cats can become infected by eating infected rodents, birds or other small animals. The parasite develops in the cat’s intestine and is shed in feces for one to three weeks. The feces containing Toxoplasma eggs can remain infectious in soil for over a year. Humans can become infected through accidental ingestion of contaminated soil or water.

Eating undercooked contaminated meat is a common source of infection. Cat owners may also be exposed if they clean their cat’s litter box and touch their mouth before washing their hands (

Most infected people do not show any symptoms. However, those with weakened immune systems may experience flu-like symptoms, muscle aches, swollen lymph nodes and other issues. Eye infections are also possible, which can lead to vision loss.

Cat Scratch Disease

Cat scratch disease (CSD), also known as cat scratch fever, is caused by the bacteria Bartonella henselae. Cats can carry this bacteria in their bloodstream and saliva. If a cat scratches or bites a person and breaks their skin, the bacteria can be transmitted to humans. According to research, the average annual incidence of CSD is approximately 4.5 cases per 100,000 people in the United States, or around 0.005% of the population. It is one of the most common diseases transmitted by cats to humans [1].

The symptoms of cat scratch disease include fever, fatigue, headache, and loss of appetite. Within 3-10 days after being scratched or bitten by a cat, a papule or pustule may form at the injury site, followed by regional lymph node swelling, which is the most common clinical sign. In most people, the disease is self-limiting and symptoms resolve within 2-4 months. However, complications can occur in 5-10% of patients, including neurological issues, eye infections, and arthritis [2].

To prevent cat scratch disease, it is recommended to adopt cats only from reputable sources, keep cats indoors to reduce hunting opportunities, and avoid playing roughly with cats. Cats should also be routinely checked and treated for fleas. If scratched or bitten, the wound should be thoroughly cleansed. Antibiotics are generally not necessary except in high-risk patients. Overall, cat scratch disease is usually not life-threatening for healthy individuals [3].



Rabies is a viral disease that affects the central nervous system and is transmitted from infected mammals to humans and other mammals. It is caused by the rabies virus (PetMD, WHO). Rabies can be transmitted through the bite or scratch of an infected animal. The vast majority of rabies cases in humans are caused by dog bites (WHO). However, cats can also transmit rabies. While rabies in cats is rare, with domestic animals accounting for only 7.6% of reported rabies cases (Alley Cat Allies), it is still a risk. Once a human or animal begins showing symptoms, rabies is almost 100% fatal (PetMD, WHO).

Initial symptoms of rabies in cats include behavior changes, increased vocalization, loss of appetite, weakness, disorientation, and paralysis (PetMD). As the disease progresses, cats may bite at imaginary objects, have seizures, and show signs of hyperactivity. Eventually paralysis will set in, leading to death. In humans, initial symptoms include fever, headache, and general weakness or discomfort. As the disease progresses, more specific symptoms arise like insomnia, anxiety, confusion, hypersalivation, difficulty swallowing, and hydrophobia (fear of water). After neurological symptoms appear, death usually occurs within a few days (WHO).

There is no effective treatment once clinical signs appear. However, rabies can be prevented through vaccination of domestic animals like cats and dogs and by prompt post-bite vaccination and immunoglobulin treatment in humans (WHO).


Ringworm, also known as dermatophytosis, is a fungal skin infection caused by dermatophyte fungi such as Microsporum canis. Ringworm is common in cats, with studies estimating prevalence between 2.7% to 37% worldwide. The fungus is transmitted by direct contact with an infected cat or its bedding and typically causes circular patches of hair loss and scaling of the skin. Symptoms often start with a dull, greasy look to the coat and development of crusts and hair loss in a circular pattern. As the name suggests, infected areas often have a ring-like appearance. Ringworm can spread from cats to humans through direct contact with the skin or exposure to contaminated objects. Therefore, treatment of infected cats combined with proper hygiene helps reduce transmission [1].

Cat Flea Tapeworm

The cat flea tapeworm is caused by the Dipylidium caninum parasite. This intestinal tapeworm is common in cats, with a prevalence of 2-56% depending on the geographic region. Cats become infected after ingesting an infected flea during grooming. The tapeworm larvae live inside the flea until they are transmitted to the cat’s small intestine after being swallowed.

Symptoms of a cat flea tapeworm infection include mild gastrointestinal upset such as diarrhea, vomiting, abdominal discomfort, and weight loss. Pet owners may also notice rice-like tapeworm segments in their cat’s stool or around their anus. These segments contain tapeworm eggs and can become infectious to humans if accidentally ingested. Treatment involves deworming medication prescribed by a veterinarian to eliminate the parasite.

To prevent infection, monthly flea control and prevention is recommended. Keeping the home and environment clean can also reduce flea exposure. Annual fecal examinations help detect any tapeworm infections so they can be treated promptly.

Campylobacter Infection

Campylobacter infection in cats is caused by Campylobacter bacteria, specifically Campylobacter jejuni. Up to 45 percent of stray cats carry the Campylobacter bacteria according to PetMD. The bacterium is shed through the feces, where other animals and humans may come into contact and get infected.

Transmission occurs through ingestion or contact with feces containing the bacteria. Humans can get infected through contact with an infected cat’s feces or litter box and by ingesting contaminated food or water. The most common symptoms in humans include diarrhea, cramping, abdominal pain, fever, headache, nausea and vomiting.

Salmonella Infection

Salmonella infection in cats is caused by Salmonella bacteria. According to the Swedish Veterinary Association, infections caused by Salmonella spp are common in cats worldwide, with the exception of the Nordic countries (Sweden, Norway, and Finland) [1]. The prevalence is estimated to be 1-18% in healthy cats [1].

Salmonella is transmitted via the fecal-oral route. Infected cats shed the bacteria in their feces intermittently or continuously. Transmission occurs when other cats ingest the contaminated feces directly or indirectly. Salmonella can also be spread through contaminated food and water [2].

Symptoms of salmonellosis in cats include fever, lethargy, vomiting, diarrhea (which may contain blood or mucus), dehydration, weight loss, and abdominal pain and discomfort. Most cats recover fully with treatment, but salmonellosis can be fatal if untreated, especially in kittens and older cats [3].



Leptospirosis is caused by bacteria of the genus Leptospira and is spread through the urine of infected animals. In cats, leptospirosis is most commonly caused by the bacteria Leptospira interrogans. The prevalence of leptospirosis infection in cats is relatively low compared to dogs, with less than 10% of cats exposed based on antibody testing. However, the risk increases for outdoor and stray cats who have exposure to rodents and other wildlife that can carry the bacteria.

Leptospira bacteria are mainly spread through contact with the urine of infected animals. Cats can become infected through exposure of mucous membranes or broken skin to contaminated urine or environments. Ingestion and venereal transmission are also possible. After an incubation period of 4-20 days, infected cats may show symptoms like fever, lethargy, vomiting, diarrhea, jaundice, and kidney or liver failure. However, many cats do not show symptoms.

To prevent spreading leptospirosis, cats with confirmed infections should be isolated and have their urine decontaminated. Prompt treatment with antibiotics like doxycycline is important, as well as supportive care for kidney and liver function. Vaccination can provide protection from some Leptospira serovars. Since leptospirosis is zoonotic, caregivers should use gloves and thoroughly wash hands when handling animals potentially infected with Leptospira.


In conclusion, while there are several diseases that cats can transmit to humans, many of them can be prevented through proper hygiene and veterinary care. The main diseases to be aware of are toxoplasmosis, cat scratch disease, rabies, ringworm, cat flea tapeworm, campylobacteriosis, salmonellosis, and leptospirosis.

To prevent disease transmission from cats, it’s important to wash hands after handling cats, avoid scratches and bites, keep cats indoors and away from rodents, deworm and deflea cats regularly, keep cats up to date on vaccines like rabies, and take cats to the vet annually for wellness checks. Pregnant women and those with weakened immune systems should take extra precautions around cats.

While zoonotic disease transmission is possible from cats, the risk is quite low for indoor cats that receive regular veterinary care. With proper precautions, cats can make wonderful pets for people of all ages.

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