Everything You Need to Know About Coccidia in Cats A Relentless Parasite

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Coccidia is a parasite that's hard to kill and can be quite harmful and even fatal to your precious feline. Learn all you can about these parasites, to keep your cat safe and healthy.

A cat with diarrhea may have coccidia, a potentially nasty and dangerous parasite. Find out what coccidia in cats looks like, what it can do, and how to get rid of it.


Coccidia are a group of microscopic parasites that can cause a disease called coccidiosis in kittens and cats.

Symptoms: Symptoms include watery stool with mucus or blood, fever, and, in some cats, neurological problems such as depression or convulsions.

About a third of all cats in the U.S. already have coccidia, but most infected cats never develop symptoms. Asymptomatic cats are not generally thought to be in peril from the parasite, unless their immune symptoms are compromised in other ways (including stress). If so, they may also begin to show signs of coccidiosis.

Very young, very old, sick, or stressed cats are the most susceptible, but all cats who carry the parasite are contagious.

Prognosis: Cats can die from the disease, though many recover with treatment.


The short answer is yes, but it’s unlikely.

Dogs, humans, and other animals do have their own forms of coccidia, but most coccidians are very host-specific. That is, most coccidia species that live in cats can’t live in dogs or humans, and vice versa.

  • Toxoplasmosis: There are exceptions to the rule — there are a few coccidia parasites that can infect cats, humans, and dogs. The most common, Toxoplasma, causes toxoplasmosis, a disease that’s especially dangerous for pregnant women.
  • How Are Coccidia Spread Among Humans? Most human cases of toxoplasmosis come from contact with contaminated soil, water, or food, not from cats. Still, it’s important to use good hygiene around cats and cat feces, especially if a cat’s coccidia status is unknown.
  • How Are Coccidia Spread From Cats to Dogs? If your dog has a tendency to get into the kitty litter to play with or eat cat feces (ick!), do all you can to discourage this behavior.


Cats can catch coccidia the same way humans do: from contact with feces or by eating infected animals, such as rodents.

Contact with feces need not be direct since one cat can easily track the microscopic spores out of the litter box and all over the house to infect others.

Kittens frequently get the parasite from contact with their mother’s bodies while nursing. Infected kittens less than six months old almost always get sick since their immune systems are immature. Coccidia is also frequently passed among cats at shelters.

Some forms of coccidia, such as Toxoplasma, use rodents as alternate hosts, so cats get infected by eating them.

Creepy fact: Toxoplasmosa gets itself back inside a cat by altering the rat’s sexual response. Some rats who are infected will approach cats rather than avoid them because the parasite makes them mistake a cat’s scent for rat sex pheromones. These rats are more likely to be eaten by cats — mission accomplished for the parasite.


It is not possible to completely protect against coccidia since coccidia spores can live for more than a year and are almost impossible to kill. Most disinfectants don’t work, and the ones that do kill the parasite can, unfortunately, be toxic to cats as well.

If your cat is pregnant, have her tested before she gives birth so you can protect her kittens?

Coccidia eggs are not infectious until they form spores hours or days after leaving the cat. Frequent litter box changes and excellent hygiene help prevent the spread of the parasite, especially in shelters or catteries.

Cats infected with coccidia should be isolated from other animals during treatment, and their boxes should be kept very clean.

  • Reinfection

Once cats are treated and recover from coccidia, they often re-infect themselves from spores left over inside the house.


  • Diagnosis

If you suspect your cat has coccidiosis, go to the vet. Coccidia eggs are very small and do not show up on fecal tests designed for worm eggs, so make sure your vet knows you suspect coccidia. Infected cats don’t always shed eggs, so false negatives are possible. Coccidia can also sometimes show up in blood tests.

  • Treatment

Sulfa drugs are the primary treatment for coccidia infection, though there are other options as well. Your cat may also require treatment for dehydration.

Since adult cats rarely show coccidiosis symptoms unless they are ill or stressed, you may have an underlying health problem to deal with as well.


The majority of cats who have been treated with antibiotics will fully recover their health. However, total immunity after infection and treatment is unlikely. Most adult cats who have been affected will become carriers of the organism, which they can spread through their own feces. For this reason, especially clean litter boxes are important. Nevertheless, even adult carriers of coccidia can live symptom-free, and remain healthy in all other aspects of their lives.

Frequently Asked Questions

What are the symptoms of coccidia in cats?

Coccidia is a type of protozoan parasite that can infect cats. The symptoms of coccidia in cats can vary depending on the severity of the infection and the age and overall health of the cat. Diarrhea is the most common symptom and can range from mild to severe. Diarrhea may be bloody or contain mucus. Cats with coccidia may vomit, especially if the infection is severe. Cats with coccidia may lose their appetite and become lethargic. Due to diarrhea and vomiting, cats with coccidia may become dehydrated. Symptoms of dehydration can include dry mouth, sunken eyes, and lethargy. If the infection is severe and the cat is not eating, it may experience weight loss. In rare cases, coccidia can cause anemia, which can cause pale gums, weakness, and lethargy.

What does coccidia poop look like?

Coccidia is a protozoan parasite that can infect the intestinal tract of cats, and the appearance of the cat's feces can be an indicator of infection. However, it is important to note that the appearance of the feces alone is not a reliable way to diagnose coccidia. A definitive diagnosis can only be made through a fecal test performed by a veterinarian. In some cases, the feces of a cat with coccidia may appear loose, watery, or diarrhea-like and may contain mucus or blood. The feces may also have a foul odor. However, it is important to note that these symptoms can also be indicative of other intestinal issues or infections. If you suspect that your cat may have coccidia or any other intestinal issue, it is important to seek veterinary care. A veterinarian can perform a thorough examination and diagnostic tests to determine the cause of the symptoms and develop an appropriate treatment plan.

Is cat coccidia contagious to humans?

Cat coccidia is not considered highly contagious to humans, but it is possible for people to become infected with some species of coccidia that infect cats. The most common species that can potentially infect humans are Toxoplasma gondii, which is transmitted through the feces of infected cats. However, it is important to note that the risk of transmission from cats to humans is generally low, and the majority of people who become infected with coccidia do not experience any symptoms or complications. To reduce the risk of infection, it is important to practice good hygiene when handling cat litter boxes or feces. This includes washing hands thoroughly with soap and water after handling the litter box or coming into contact with feces and avoiding contact with the mouth or face during the process. Pregnant women and people with weakened immune systems should take extra precautions and consult with their healthcare provider about any potential risks.

How do cats catch coccidia?

Cats can catch coccidia through ingestion of infected feces, contaminated soil or water, or by eating infected prey. The protozoan parasite lives in the intestines of infected animals, and the oocysts (eggs) are shed in the feces. The oocysts can survive for long periods in the environment and can infect other cats that come into contact with the contaminated feces or soil. Cats that live in crowded or unsanitary conditions or that have weakened immune systems due to other illnesses are at a higher risk of developing coccidia. Kittens are also more susceptible to coccidia infections because their immune systems are not fully developed.

What is the fastest way to get rid of coccidia?

There are several medications that are effective against coccidia, including sulfadimethoxine, trimethoprim-sulfadiazine, and ponazuril. The specific medication and duration of treatment will depend on the severity of the infection and the health of the cat. Coccidia oocysts (eggs) are very resistant to many disinfectants and can survive for long periods of time in the environment. However, there are some disinfectants that can be effective against coccidia, such as a 10% ammonia solution or a 3% hydrogen peroxide solution. It is important to thoroughly clean and disinfect litter boxes, surfaces, and other areas that may have been contaminated with feces to prevent reinfection and the spread of coccidia. In addition, incineration of feces or steam cleaning, immersion in boiling water, and other high-temperature methods can be effective in killing coccidia. These methods are more reliable in ensuring the elimination of coccidia oocysts than most disinfectants. It is important to note that prevention is key in controlling the spread of coccidia. Practicing good hygiene and sanitation measures, including regular cleaning and disinfection of litter boxes and living areas, as well as regular veterinary care and deworming, can help reduce the risk of coccidia infection in cats.

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This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian with respect to your pet. It has, however, been verified by a licensed veterinarian for accuracy.

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