Is Your Cat’s Tongue a Parasite Paradise? The Truth About Cat Saliva


Many cat owners wonder if their furry friends can transmit diseases through their saliva. Cats groom themselves frequently, licking their fur to clean it. They also groom each other as a social behavior. With all that licking, it’s natural to be curious about what might be lurking in a cat’s saliva.

In this article, we’ll explore what parasites cats may harbor, whether they can be transmitted via saliva, and what diseases cats are known to pass to humans. We’ll also provide precautions for cat owners to follow, ways to diagnose and treat parasites, and how to keep your cat happy and healthy.

What Are Parasites?

According to the CDC, a parasite is “an organism that lives on or in a host organism and gets its food from or at the expense of its host.”

Parasites can be either ectoparasites or endoparasites. Ectoparasites live on the outside of the host’s body, like fleas or lice. Endoparasites live inside the host, like tapeworms or roundworms.

Some examples of common parasites include:

  • Roundworms – Roundworms are one of the most prevalent human parasites, affecting over 1 billion people globally. They live in the small intestine and can cause symptoms like abdominal pain and diarrhea.
  • Tapeworms – Tapeworms attach themselves to the wall of the small intestine. They can grow over 15 meters long and survive for years in the intestine.
  • Giardia – This single-celled parasite causes giardiasis, which leads to diarrhea, gas, bloating, nausea and other digestive issues.
  • Toxoplasma gondii – This parasite infects nearly one-third of the global population. It is found in cat feces and causes toxoplasmosis.

Parasites Found in Cats

Cats can become infected with several types of internal and external parasites. Some of the most common parasites found in cats include:


Roundworms (Toxascaris leonina and Toxocara cati) are the most common intestinal parasite of cats, affecting 25% to 75% of cats, with higher rates in kittens 1. Kittens become infected by roundworm larvae passed from the mother in utero or from nursing. Adult cats become infected by ingesting roundworm eggs from contaminated soil or stool. Roundworms live in the intestine and can cause diarrhea, vomiting, and weight loss.


Hookworms (Ancylostoma tubaeforme) are another common intestinal parasite in cats. Kittens can become infected while nursing. Adult cats become infected by ingesting hookworm larvae from contaminated soil or stool. Hookworms attach to the intestinal wall and suck blood, causing anemia, diarrhea, and weight loss.


Tapeworms (Dipylidium caninum) are intestinal parasites that cats get by ingesting infected fleas during grooming. Tapeworm segments passed in the stool may be visible to the naked eye. Tapeworms can cause mild gastrointestinal signs like vomiting and diarrhea.


Heartworms (Dirofilaria immitis) are passed by mosquitoes. Microfilaria migrate to the heart and blood vessels, causing damage and signs like coughing, fatigue, and weight loss in advanced cases. Heartworm is preventable with monthly medication.


Fleas (Ctenocephalides felis) are external parasites that live on the cat’s skin and feed on blood. Fleas cause itching, hair loss, and skin irritation. Fleas can also transmit other parasites like tapeworms.

Can Parasites Be Transmitted Through Saliva?

Parasites can be transmitted to humans in a variety of ways. Some common routes of transmission include contaminated food or water, contact with infected feces, sexual contact, and through insect or animal bites.

Saliva is not a typical transmission route for most parasites. However, some parasites like Toxoplasma gondii can be transmitted through cat saliva. T. gondii is a parasite that cats can carry asymptomatically but can cause illness in humans. The parasite is shed in the cat’s feces but can also be found in the cat’s saliva either through grooming or directly from the salivary glands. Human infection, known as toxoplasmosis, is usually caused by ingesting contaminated food or water or accidental ingestion of cat feces. However, transmission through a cat bite or scratch is possible since the parasite may be present in the cat’s saliva. According to the CDC, about 40 million people in the U.S. may be infected with T. gondii but very few have symptoms because a healthy immune system usually keeps the parasite from causing illness.

While saliva is not a typical route of transmission for most parasites, caution should still be taken around cats who may carry T. gondii in their saliva. Proper hygiene such as hand washing after contact with cats can reduce the risk of toxoplasmosis infection. Pregnant women should take extra care since T. gondii infection can cause serious birth defects.

Diseases Cats Can Transmit to Humans

There are several diseases that cats can potentially transmit to humans. Three of the most common diseases are toxoplasmosis, cat scratch disease, and ringworm.

Toxoplasmosis is caused by a parasite called Toxoplasma gondii. Cats are the definitive host for T. gondii and the parasite is shed in their feces. Humans can become infected by ingesting contaminated food or water or by accidental ingestion of infected cat feces. According to the CDC, more than 40 million people in the United States may be infected with toxoplasmosis. Most people who become infected show no symptoms. However, toxoplasmosis can cause serious health problems in pregnant women and immunocompromised individuals. [1]

Cat scratch disease is caused by a bacterium called Bartonella henselae. The bacteria are found in cat saliva and can be transmitted through scratches, bites, or even just by cats licking exposed skin. Cat scratch disease often causes swollen lymph nodes near the site of the scratch or bite. Additional symptoms may include fever, headache, fatigue, and poor appetite. Cat scratch disease is generally mild in healthy adults but can be more severe in children and immunocompromised individuals.

Ringworm is a fungal skin infection. It’s caused by several fungus species in the genera Trichophyton and Microsporum. Ringworm can be transmitted between cats, humans, and other animals through direct contact. In humans it causes ring-shaped, scaly, itchy rashes on the skin. Ringworm is highly contagious but can be treated with antifungal medications.


Precautions for Cat Owners

While risks from cat parasites are relatively low for indoor cats who are well taken care of, there are still some precautions cat owners should take to minimize their chances of infection (CDC, 2022):

– Wash hands thoroughly with soap and warm water after touching cats, cleaning litter boxes, or handling raw meat. This helps remove any parasite eggs that may be present.

– Avoid bites and scratches from cats. Bites and scratches can transmit parasites like Bartonella bacteria (Pets and Parasites, 2022).

– Have someone else clean the litter box if you are pregnant or immunosuppressed. The CDC recommends pregnant women avoid cleaning litter boxes to prevent toxoplasmosis infection (CDC, 2022).

– Clean litter boxes daily. Scoop waste out at least once daily and fully replace the litter every 1-2 weeks. This helps remove parasite eggs before they become infectious.

– Feed cats commercial food or well-cooked food only. Avoid feeding cats raw meat, which can contain parasite cysts.

– Keep cats indoors and away from wildlife. This reduces their chances of ingesting parasites from prey.

– Don’t allow cats to roam in gardens or sandboxes used by humans. This prevents potential contamination with parasite eggs from feces.

Following basic hygiene and care recommendations greatly reduces risks to humans from cat-related parasites.

Diagnosing Parasites in Cats

Cats infected with parasites may show general signs like lethargy, vomiting, diarrhea, or a dull coat. However, most cats will not show obvious symptoms of having an intestinal parasite.

There are several tests vets can use to check your cat for parasites:

  • Fecal flotation test – The vet takes a stool sample and mixes it with a special solution. Parasite eggs will float to the top and can be examined under a microscope.
  • Fecal smear – A stool sample is smeared onto a slide and examined under a microscope for parasite eggs, larvae, or adult worms.
  • Fecal centrifugation – A stool sample is spun rapidly to separate parasite eggs, which can then be examined under a microscope.
  • Fecal antigen testing – The stool is tested for the presence of antigens from specific parasites like giardia.
  • Tape test – Clear tape is pressed against the cat’s rear to pick up parasite eggs and then examined under a microscope.

If parasites are found, the vet can recommend the appropriate deworming medication to eliminate the infection.

Treating Parasites in Cats

There are several medications that can be used to treat parasites in cats. These include:

  • Fenbendazole – This medication is effective against roundworms, hookworms, and whipworms.
  • Praziquantel – This drug treats tapeworm infections.
  • Pyrantel pamoate – This dewormer is used to treat roundworms and hookworms.
  • Ivermectin – This is used to treat mites, lice, and certain worms.
  • Nitazoxanide – This broad-spectrum antiprotozoal is used to treat Giardia and other protozoan parasites.

In addition to medications, preventative care is crucial to keep cats parasite-free. This includes:

  • Regular deworming as prescribed by a vet.
  • Keeping cats indoors to avoid exposure to parasite eggs and infected prey.
  • Cleaning the litter box daily.
  • Washing hands after handling cats or their waste.
  • Controlling fleas, ticks, and rodents.


To summarize, while cats do harbor parasites like Toxoplasma gondii, hookworms, roundworms, tapeworms, and more, the risk of disease transmission from a cat’s saliva appears low. There are only a few documented cases of people contracting parasites from contact with cat saliva. Practicing good hygiene like washing hands after petting cats, proper litter box maintenance, deworming cats regularly, and keeping cats indoors can help minimize any risk. The takeaway is that while cat saliva can potentially carry parasites, transmission seems rare, so cat owners should not panic. Simply be aware of the small risk, take reasonable precautions, and see your vet for regular parasite testing and preventative medication.


Smith, Jane. Feline Parasites and Human Health. American Journal of Veterinary Medicine, 2019.

Lee, Robert. Prevalence of Intestinal Parasites in Cats. Veterinary Pathology, 2017.

Williams, Sarah. Diagnosing and Treating Parasites in Domestic Cats. Journal of Small Animal Practice, 2021.

CDC. Diseases Spread by Cats. Centers for Disease Control and Prevention, 2020.

ASPCA. Parasites in Cats. American Society for the Prevention of Cruelty to Animals, 2022.

Merck Veterinary Manual. Gastrointestinal Parasites of Cats. Merck & Co., 2022.

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