Coccidia in Cats

Coccidia oocyst under the microscope

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Coccidia may not be visible to the naked eye but that doesn't mean it can't cause problems in your cat. This little parasite can lie undetected in your cat so it's important to know how to see if your cat is infected and if so, how and when to treat it.

What Is Coccidia in Cats?

Coccidia is a protozoan that infects the intestinal tract of cats and other species and causes coccidiosis. It is a single-celled organism and while it isn't a worm or an egg, it is still a type of intestinal parasite. There are many different species of coccidia but two species of coccidia are most common in cats - Isospora felis and Isospora rivolta. These parasites live in the cells of the intestines.

Toxoplasma and Cryptosporidium are also species of coccidia but the Isospora species are the ones that are most typically referred to as coccidia. Toxoplasma and Cryptosporidium are much less common than regular Isospora coccidia is in cats.

Signs of Coccidia in Cats

Like other intestinal parasites, coccidia commonly affects the stool of an infected cat.

Signs of Coccidia in Cats

  • Diarrhea
  • Crying when defecating
  • Sensitive when its belly is pressed
  • Dehydration with sunken eyes and skin tenting
  • Vomiting
  • Loss of appetite
  • Lethargy

Most cats that are showing symptoms of a coccidia infection will have watery diarrhea. This is an obvious symptom but many different problems and diseases can cause abnormal stools. If a coccidia infection worsens, a cat may have abdominal discomfort and cry when defecating or show dislike if its belly is pressed. If diarrhea is left untreated, dehydration can occur resulting in sunken eyes and skin tenting. Skin tenting is most obvious over the shoulder blades when you lift your cat's skin up and it stays in a tent shape instead of snapping back onto the body. Finally, with severe infections, coccidia can also cause vomiting. In Toxoplasma infections, cats may show a lack of appetite and be lethargic but like cats with infections of other types of coccidia, most show no symptoms at all.

Causes of Coccidia in Cats

In order for a cat to become infected with coccidia it needs to consume the parasite. This is most commonly done when a cat ingests an infected mouse or another cat's feces. When a cat swallows the oocyst, which is the immature, infectious form of coccidia, the cat develops coccidiosis.

Diagnosing Coccidia in Cats

If your cat is showing any signs of coccidiosis, your veterinarian will check your cat's feces under the microscope to look for coccidia oocysts. This parasite is very tiny compared to other intestinal parasites and can be easily missed so a very thorough fecal analysis, or multiple fecal analyses, must be performed in order to find it.

If your veterinarian is concerned that your cat may have one of the less common types of coccidia such as Toxoplasma or Cryptosporidium, they may need to run additional specific tests. A series of blood or fecal samples are often taken in those cases.

Treatment of Coccidia in Cats

In order to treat coccidiosis in a cat showing symptoms, your cat will need a specific type of anti-parasitic medication to kill the parasite. Usually a drug called trimethoprim-sulfonamide is prescribed and given orally to your cat for about a week in order to treat the infection. Probiotics, prebiotics, and special diets may also be needed but while coccidia is a very common parasite in cats, many do not require treatment if they aren't showing symptoms. Most cats seem to spontaneously get rid of the parasite on their own.

How to Prevent Coccidia in Cats

The best way to prevent your cat from getting coccidia is to keep it indoors and don't allow it to chase or play with mice. If you have multiple cats and one is showing symptoms of coccidia and tests positive for the infection, be sure to keep your other cats away from the litter box that the infected cat uses. Avoiding feeding your cat uncooked meat can also decrease the likelihood that it will ingest coccidia oocysts.

Is Coccidia Contagious to Humans?

The common Isospora types of coccidia are not a concern for humans but if your cat is diagnosed with Toxoplasma or Cryptosporidium you can be infected. Immune compromised individuals have the highest risk of infection but by practicing good hygiene techniques and properly disposing of cat feces you can minimize the risk of contracting these zoonotic diseases.