Coccidia (Isospora and Eimeria) are one-celled organisms called protozoa that invade the intestinal lining of dogs. Each species of coccidia causes disease in only one species of host, but other animals (rodents) can contribute to transmission in the life cycle. Adult dogs often carry the organism, showing no clinical signs, and serve as a source of infection for puppies. The eggs (oocysts) pass in the stool, are nearly impossible to destroy, and can survive for years in the environment. Steam sterilization is the only practical means to destroy the oocysts in a kennel. Signs can include a bloody, mucoid diarrhea, abdominal pain, dehydration, vomiting, anorexia, and death. Totally eliminating this parasite is nearly impossible, so stringent control methods are necessary. Strict sanitation and rodent control are vital. Medications are often used as a prevention and not just for treatment in adults, nursing mothers, and puppies.