Intestinal coccidiosis is caused by infection with any one of the coccidia species: Isospora, Besnoitia, Hammondia, Sarcocystis, Toxoplasma, or Cryptosporidium.  Infection with Isospora is most common in dogs.  Infection occurs when infective eggs are ingested from a contaminated environment, or an infected transport host is ingested.  Rodents and other small prey can carry coccidia, making ingestion of their tissues and feces infective.  Infection with coccidia can also occur when uncooked meat from infected herbivores such as cows or sheep is ingested.  After ingestion of ocysts, the incubation period is usually 6 to 10 days.

The presence of coccidia in the feces of dogs is fairly common.  Up to 72% of dogs may have some level of infection with coccidia.  Multiple dog kennels are most prone to infection.  The major sign of coccidiosis is diarrhea which is soft or watery, and may contain mucus, blood, and shreds of intestinal epithelium.  Vomiting, dehydration, loss of appetite, weight loss, and decreased activity level are other signs associated with coccidia.  Diarrhea is typically most severe in puppies under 4 months of age.  Adult dogs may harbor coccidia with few clinical signs, but serve as a source of infection to puppies.  Diagnosis is made by microscopically identifying oocysts in feces.

Strict sanitation is important for prevention of infection.  All cages and kennel runs should be cleaned with steam or a strong sodium hydroxide solution to kill oocysts.  Prompt removal of feces helps reduce exposure to infective feces. Elimination of rodents and rodent feces will reduce coccidia in the environment.  Any meat that is fed should be thoroughly cooked.  Older dogs that may be asymptomatic carriers should be kept separate from young puppies.

Puppies showing clinical signs of coccidiosis should be treated orally with sulfadimethoxine (Albon or Bactrovet) at 25 to 30 mg/lb body weight per day for 10 days.  Amprolium (Corid) is not approved for use in dogs, but has been used effectively in kennel operations.  One-quarter teaspoon of 20% powder per four puppies is mixed with the puppy food for 10 days, or 1.5 to 2 tablespoons of 9.6% amprolium solution can be mixed with one gallon of free-choice water.  With severe cases of coccidiosis, secondary intestinal bacterial infections are common, and treatment may need to be prolonged.

Patricia Schenck, DVM, PhD
Veterinary Nutritionist
September, 1997