Pet Factsheets


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Coccidiosis is an intestinal condition caused by a single-celled parasite. Dogs and cats swallow cysts containing the parasite from contaminated environments, usually during grooming. Cocciodiosis can be treated with an oral medication for 5-10 days.

What is coccidiosis?

Coccidiosis is an intestinal condition caused by a microscopic, single-celled parasite. There are several types of coccidia, but dogs with coccidiosis are usually infected with Isospora canis, while cats are infected with the parasite Isospora felis. The coccidia species that infect dogs do not infect cats, and vice versa. The cysts in the faeces from one dog can infect another dog, and the cysts in the faeces from one cat can infect another cat. However, the species of coccidia that affect dogs and cats generally don't infect people.

How did my cat get coccidiosis?

Infected cats shed cysts containing the parasite in their faeces. These cysts can survive in the environment for as long as a year, and other pets can become infected by swallowing the cysts from a contaminated environment (usually during grooming). Cats can also be infected by eating an infected rodent.

Once inside the pet's digestive tract, the cysts break open, and the parasite enters the intestinal cells, where it reproduces. The cell eventually ruptures, releasing the parasites and damaging the intestinal lining.

What are the signs of coccidiosis?

The main sign is watery diarrhoea that may be tinged with blood or mucus. Infected pets may also experience vomiting, a loss of appetite, and tiredness. In severely affected kittens, dehydration, weight loss, and, in some cases, death can occur.

Older pets usually have milder signs and some pets may show no signs at all but still shed the parasite cysts in their faeces.

How will my vet diagnose coccidiosis?

A faecal examination is the most common method of diagnosis. The parasite cysts are often difficult to find on a faecal exam so your vet may choose to treat your pet if he suspects coccidiosis, even if no cysts are found.

Any new pet being introduced into the home should have a faecal sample tested as soon as possible to diagnose coccidiosis or other intestinal parasite infections. Your vet may also recommend faecal tests during your pet's regular check-ups.

How is coccidiosis treated?

Several oral medications may be used to treat this condition and your pet will most likely require daily treatment for 5-10 days. If you have a multi-cat household, but only one cat showing signs of coccidiosis, it is wise to treat the other cats to prevent reinfection from other cats that may carry the parasite but show no signs. Pets (particularly kittens) with severe dehydration may need fluid therapy.

How can coccidiosis be prevented?

To prevent your cat from being infected from parasite cysts in the environment, wash his or her bedding and clean the kennel area with an ammonia product. Pick up and dispose of faeces as soon as possible, and prevent your pet hunting animals when outside.