Overview:

Coccidiosis is an parasitic disease of the intestinal tract. It is caused by intracellular microscopic protozoans (single celled organisms) called coccidia. The diseases caused by these parasites are referred to collectively 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. Symptoms are most commonly seen in kittens under 6 months of age. Most adults carry coccidia,  but their immune system keeps it in check, some adults may however shed cysts in the faeces. Symptoms can appear especially if the cat is stressed or the immune system is under attack from another cause, such as FIV.

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

What are the symptoms of coccidiosis in cat

• Diarrhoea is the most common symptom of coccidiosis. This may range from mild to severe & there may be blood & mucus in the present.
• Uveitis

Severe cases may lead to;

• Vomiting.
• Weight loss.
• Dehydration.
• Loss of appetite.
• Death.

How do cats become infected?

Nonsporulated (non-infective) oocysts are passed in the cat's faeces. Once they are on the outside, they mature. Once the oocyst  matures (which depends on environmental conditions), they become infective (sporulated oocyst). It is also possible for a rodent to pick up an oocyst & 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.

Damage to the intestinal cells leads to diarrhoea.

How is coccidiosis diagnosed?

Routine fecal examinations can detect the condition. A negative result is not a definite indication that your cat doesn't have coccidioses, 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, 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.

Fluids to treat dehydration if necessary.

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 & killing rodents.
• Proper sanitation.
• Avoiding stress where possible.
• Daily washing of food & water bowls.

References: Isospora felis Homepage