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Coccidia in Cats

By | Last Updated: 25th October 2018

What are coccidia, and coccidiosis in cats

Coccidia are a group of single-celled protozoa found within the intestinal lining of kittens and cats. These often cause an intestinal-tract infection called coccidiosis [1, 2].

Kittens, and older cats that are stressed or have a weak immune system are more likely to be affected by coccidia [1, 2]. Young cats less than six months old are more likely to get affected due to their immature immune system [2].

Signs and symptoms

Although most cats in the US carry the parasite, they do not develop any symptoms [2]. These cats are not considered to be in immediate danger unless they already have weakened immune systems impaired by stress or bacterial, viral, and fungal infections [2].

A sick cat may show the following visible signs:

  • Watery stool with blood or mucus [1, 2, 3]
  • Vomiting [1, 3]
  • Redness, swelling of the eye, unevenly shaped or small pupil, excessive tears (uveitis) [3]

Look out for the following behavior changes:

  • Eating less than normal (anorexia) [3]
  • Lethargy or panting (may be caused by dehydration) [3]
  • A reduction in overall activity, abnormal gait, and a tendency to hide behind walls and furniture (often because of abdominal pain) [3]

For a kitten, the weaning process can sometimes be stressful and may lead to parasitic infections [3]. Sometimes a stressed kitten may start displaying symptoms of coccidiosis between two weeks and six months of age [3].

Coccidia in Cats

Causes: How do cats get coccidia

Though it is mostly caused by the parasites Isospora rivolta and Isospora felis, some species of Toxoplasma, Besnoitia, Hammondia, and Sarcocystis may also be responsible [1, 3]. The infection can spread in the following ways:

  • Immature coccidia or oocysts (cysts containing zygote formed by the parasite) can enter the body through direct contact with feces of an infected cat [1]. Kittens may come in direct contact with their mother’s feces during nursing and get infected if the mother is passing infective oocysts in her stool [1, 2].
  • A cat may develop coccidiosis by consuming an infected mouse [1].
  • A kitten or puppy can contract the disease from other infected kittens, and it usually happens in animal shelters and other breeding facilities [1, 2].
  • The parasite might also contaminate food, spreading in cats and other animals who eat it.

The process of immature coccidia sporulating into a developed oocyst, either re-infecting the same cat or spreading to other cats, can take place within as little as 6 hours, though it usually takes 7-10 days [1].

Is it possible to prevent coccidia

Though prevention may not always be possible, taking the following measures may help with keeping the infection from spreading further:

  • Isolate an infected cat from other pets [2].
  • Keep their litter boxes clean during treatment for preventing the parasitic infection from spreading through the household [2, 3].
  • Sterilize the materials used for handling your cat, including their boxes, with bleach and warm water to prevent reinfections [1, 3].
  • Try to keep your cat indoors to reduce the chances of getting coccidia from infected rodents [6].
  • Give it high-quality foods to boost its immune system [6].


If any of the above symptoms are present in your cat, take it to a vet immediately [2, 3]. After going through its medical history, your vet may perform a complete physical examination along with an evaluation of its symptoms [3].

Tests include a stool analysis, where the sample is thoroughly observed because coccidia eggs are hardly visible, as they are much smaller than the intestinal worm eggs [1, 2]. Since an infected cat might not always shed oocysts in feces, blood and urine tests would likely help diagnose the infection [2].

Treatment of coccidia in cats

A mild infection may need no treatment [3]. However, in severe cases, treatment involves lessening the symptoms, monitoring your cat’s condition, and controlling the cause [3].

Treating with antibiotics

Vets usually recommend Sulfa-class antibiotics for treating feline coccidial infection because most cats readily take these for their pleasant taste [1, 2]. These oral medications are generally given for one to two weeks [1, 3].

Supportive treatment to relieve complications

If your cat shows signs of diarrhea and dehydration, it may need to be hospitalized and kept under observation [3]. Intravenous fluids may be administered to rehydrate and stabilize its condition [3].

Can coccidiosis be cured completely

Although most cats treated with antibiotics recover from coccidial infections, they do not become fully resistant to the parasite [2]. They can become carriers so that the parasites spread through their stools, increasing the risks of re-infections all through their life [2].

Is it contagious to humans

The Isospora species, the most common in cats, are not known to infect humans [1]. However, the less common Cryptosporidium can affect people with weakened immune systems, and Toxoplasma infections are particularly dangerous during pregnancy [1]. These may spread through contaminated water or meats.

Coccidial infection cannot be passed from cats to dogs because a dog is less likely to ingest the parasite from soil, swallow cat feces, or eat intermediate hosts like a mouse [5]. Puppies are often less resistant because of their maturing immune system.


    1. Coccidiosis in Cats – Vcahospitals.com
    2. Everything You Need to Know About Coccidia In Cats – Petcarerx.com
    3. Coccidia in Cats – Wagwalking.com
    4. Intestinal Parasite (Coccidia) in Cats – Petmd.com
    5. Coccidia – Petsandparasites.org
    6. Coccidia Treatment for Cats – Pets.thenest.com

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