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Coccidiosis in Cats

Coccidiosis is a parasitic disease of the intestinal tract that is caused by a microscopic protozoan (single celled organisms) called coccidia. The diseases caused by these parasites is referred to as coccidiosis.  There are many species of coccidia, and each is infective in different animals. The species of coccidia that most frequently affect cats are I. rivolta and I. felis.  Most adults carry coccidia,  but their immune system keeps it in check, some adults may however shed cysts in the faeces. Symptoms are most commonly seen in kittens under 6 months of age. Stressed cats and those who have compromised immune systems are at greatest risk of developing symptoms. 

Two very well known coccidia are toxoplasmosis and cryptosporidium which are covered in other articles.

What are the symptoms of coccidiosis in cats?

Diarrhoea is the most common symptom of coccidiosis. This may range from mild to severe and there may be blood and mucus in the present. Other symptoms may include:

  • Uveitis - Inflammation of the uvea in the eye.
  • Vomiting.
  • Weight loss.
  • Dehydration (due to loss of fluids).
  • Loss of appetite (anorexia).
  • Death.

How do cats become infected?

Nonsporulated (non-infective) oocysts are passed in the cat's feces. Once they are in the outside environment, they mature. When the oocyst  matures (which depends on environmental conditions), they become infective (known as sporulated oocyst). It is possible for a rodent to pick up an oocyst and the cat becomes infected when it eats the rodent. Each oocyst contains 4 sporozoites in each of 2 sporocysts. The "zoites" invade the intestinal cells and develop to the schizont stage. The schizonts release more zoites which invade new cells and give rise to the next generation of schizonts. There are 3 generations of schizonts. Zoites released from the last generation of schizonts invade cells and form gametocytes. The male gametocyte releases gametes which fuse with the female gametocytes and form oocysts.

It takes approximately two weeks from ingestion to symptoms of infection to occur.

How is coccidiosis diagnosed?

Routine fecal examinations can detect the coccidiosis in cats . A negative result is not a definite indication that your cat doesn't have the disease, and it may be necessary to perform repeat fecal examinations.

How is coccidiosis treated?

It isn't possible to kill the parasite, but medication is is given to inhibit coccidial reproduction. The usual treatment is sulfadimethoxine or Trimethoprim-sulfa, which is given orally. By stopping the ability of the protozoa to reproduce, time is allowed for the cat's own immunity to develop and remove the organisms.

Supportive care may need to be offered such as IV fluids to treat dehydration.

Can I become infected?

I. felis which is the most common form of coccidiosis in cats does not affect humans. However it is possible to become infected with toxoplasmosis from cats.

How can I prevent coccidiosis?

  • Good hygiene. Ensure you scoop out your cat's litter tray at the very least once a day.
  • Preventing your cat from hunting and killing rodents.
  • Proper sanitation.
  • Avoiding stress where possible.
  • Daily washing of food and water bowls.

Also see:

Giardia in cats   Cryptosporidium in cats