Intestinal Parasite (Cryptosporidium) in Cats

Cryptosporidium is a parasite that is found worldwide and can cause diarrhea disease in a variety of animals. The parasite is spread through the consumption of the eggs in the feces of an infected host. This can happen in cats through shared litter boxes, consumption of contaminated water or prey species, and mutual grooming. These eggs can survive in the environment for several months and are resistant to many methods of cleaning and disinfection. This parasite can spread to humans and infect those that are immunocompromised or at higher risk of disease.

Although infection with Cryptosporidium species is common in cats, illness is generally only seen in immunocompromised cats. If symptoms also include lethargy, lack of appetite, or signs of dehydration (dry mucous membranes, reduced skin turgor), urgent veterinary care is indicated.

Immunocompromised individuals are at higher risk to develop symptoms from the infection. Symptomatic infection with Cryptosporidium can be life-threatening and diarrhea is always cause for some concern, and warrants veterinary attention by itself.

Rarely, a severe infection can cause weakness and collapse.

Cryptosporidiosis is caused by ingestion of eggs from fecal-contaminated environments, food, objects, or water. Risk factors for symptomatic disease include immaturity, concurrent disease/immunocompromised individuals, and small size.

In cats, cryptosporidiosis is usually asymptomatic.

Cryptosporidiosis can also lead to dehydration. Symptoms of dehydration include dry mucous membranes and reduced skin elasticity.

Diagnostics of a possible case of cryptosporidiosis require a full physical exam, blood work, urinalysis, and fecal parasite testing. Diagnosis can be challenging as eggs are too small to be found on routine fecal tests; special testing is often required to identify the organism. Cats which are otherwise healthy do not usually show signs of illness, therefore those showing signs are more likely to have concurrent disease or to be generally immunocompromised. Further feline leukemia and feline immunodeficiency virus testing is recommended for these cats.

The primary goal of treatment is to stop diarrhea, rather than to completely eradicate the organism. Cryptosporidium is resistant to many medications. Antibiotics may work to reduce the number of organisms, but only the host’s immune system can clear the infection. Treatment is therefore supportive, with antidiarrheal medications and IV fluid therapy.

Persistent cases indicate an underlying cause of immunodeficiency. Symptoms will last longer, be more severe and possibly life-threatening in immunocompromised cats. Prognosis for symptomatic individuals is good with treatment, though reinfection can occur.

As this parasite is contagious via the fecal-oral route, good hygiene practices are essential to preventing infections. Appropriate vaccination and keeping cats indoors can help prevent feline leukemia and feline immunodeficiency viruses, which predispose cats to other illnesses. The parasite is potentially contagious from cats to humans, but is generally not a concern in immunocompetent people.

Immunocompromised individuals may need to refrain from contact with cats with diarrhea, stray cats, and cats under the age of 6 months.

Infection with Cryptosporidium is common in cats, but resultant illness is rare.

• Antidiarrheal medications
• Antibiotics
• Supportive care (IV fluids)