Fecal samples screened at Westgate Pet Clinic are positive for coccidia more than any other type of intestinal parasite. Coccidia are parasites, but they are not worms. They are single-celled organisms or protozoa. The most common species of coccidia that affect cats and dogs belong to the genera Isospora (also known as Cystoisospora). Isospora species infect the intestines in cats and dogs and can cause disease, referred to as intestinal or enteric coccidiosis.
What are the signs of Intestinal Coccidiosis?
Infection with Isospora can cause bloody or watery diarrhea, weight loss, dehydration, and, in more serious cases, anorexia, vomiting, and depression. In severe cases, intestinal coccidiosis can be fatal. Intestinal coccidiosis is more common with Isospora infections in younger and stressed cats and dogs, or pets with weaker immune systems. Many healthy adult cats and dogs who are infected with Isospora show no clinical signs of disease.
How did my cat/dog get infected with Isospora?
Infection with Isospora occurs when a cat or dog ingests the infective stage of the protozoa, the sporulated oocysts. Since oocysts are passed in an infected pet’s stools, Isosporaare usually transmitted through the fecal-oral route. Rarely, infection can occur when a cat or dog eats a transport or a paratenic host, another animal which has oocysts dormant in its body. Since Isospora are highly species-specific, the transport or paratenic host (usually a rodent or an insect) would have to have been infected with the particular species ofIsospora that affect cats (Isospora felis or I. rivolta) or dogs (Isospora canis, I. ohioensi, I. burrowsi, or I. neorivolta) to cause feline or canine intestinal coccidiosis. That Isospora are species-specific also means that a dog cannot get coccidiosis by ingesting a cat’s or rabbit’s feces.
How is Intestinal Coccidiosis diagnosed and treated?
Intestinal coccidiosis is diagnosed based on finding Isospora oocysts in a fecal sample of a cat or dog who is also showing gastrointestinal signs. Prevalence data indicate that over one-third of cats and dogs may be infected with Isospora. Coccidiosis, the disease associated with an infection, is less common since the immune systems of healthy cats and dogs are strong enough to resolve the infection before they become symptomatic. Westgate Pet Clinic veterinarians recommend treating Isospora infections in kittens and puppies and in adult cats and dogs who are showing clinical signs of illness. Since coccidia are not worms, they cannot be treated with typical dewormers given to puppies and kittens. Intestinal coccidiosis is treated with an antibiotic that is coccidiostatic—it slows down the reproduction of Isospora. This allows the host’s immune system to catch up and resolve the infection. In severe infections, supportive care such as fluids to treat dehydration, assistive feeding, and anti-diarrheal medications may be needed.
What can be done to prevent Intestinal Coccidiosis?
Since Isospora infections most often occur when a cat or dog ingests oocysts that have been passed in an infected pet’s stools, environmental clean-up is critical. Once passed into the environment, oocysts can reach an infective stage in hours (as compared to days or weeks with intestinal worms). The oocysts are also very hearty, surviving for months in the environment—even longer if they are not exposed to freezing temperatures. Oocysts are also resistant to common disinfectants. Picking up feces promptly can help prevent an initial infection, as well as reinfection with Isospora. In a household with cats or kittens infected with Isospora, litterboxes should be scooped twice daily. Fecal accidents in the house should be cleaned with a disinfectant containing a high concentration of ammonia if pets are known to have an Isospora infection. Cats and dogs should also be discouraged from eating rodents and insects from which they could contract an Isospora infection. Fortunately, since Isospora are species-specific, unlike other types of coccidia, they do not pose a health risk to humans. Practicing good hygiene is always recommended to prevent disease transmission between our patients and clients.