Coccidia are tiny single-celled parasites that live in the wall of your dog’s intestine. They are found more often in puppies, but they can also infect older dogs and cats. Dogs become infected by swallowing soil that contains coccidia or other substances in the environment that may contain dog feces.
How common is coccidal infection in dogs?
Published surveys indicate that coccidia are present in from 3% to 38% of dogs in North America.
How will coccidia affect my dog?
Coccidiosis, the disease caused by coccidia, may not cause any signs in dogs but is usually more serious in puppies. The most common sign of coccidiosis is diarrhea. More severe infections can cause dehydration and bloody diarrhea. Severely affected animals may present with anorexia, vomiting, and depression. Severe infections, especially in puppies, can kill them. Cystoisospora species are rigidly host-specific. Canine coccidia will not infect felines leading to passage of oocysts in feces. The same is true the other way for feline coccidian.
Site of Infection and Pathogenesis
Development of oocysts to infective sporulated oocysts (sporulation) does not occur above 40° C or below 20° C. Sporulation occurs rapidly (<16 hours) at temperatures between 30° C and 37° C. Sporulated oocysts are resistant to adverse environmental conditions and can survive as long as one year in moist, protected environments if they are not exposed to freezing or extremely high temperatures. Developmental stages reside in either cells lining the intestinal villus (enterocytes) or cells within the lamina propria of the villus. Maturation and emergence of asexual and sexual stages from infected cells causes cell lysis. This damage can be especially severe when caused by species that develop within cells in the lamina propria. Zoites also are found in extraintestinal tissues (i.e., mesenteric lymph nodes, liver, or spleen) of definitive or paratenic hosts. These resting or latent stages are not thought to cause clinical disease.
How do I prevent my dog from getting coccidia?
Coccidial infections can be prevented by removing your dog’s feces regularly from your yard or other areas where the dog goes to the bathroom. Because coccidia are found most often in puppies, it is important to have puppies examined for the parasite as soon as possible. Your veterinarian can perform a fecal test to diagnose coccidiosis. If your dog is infected with coccidia, your veterinarian is able to give it effective medications. Sulfadimethoxine is the only drug that is label approved for treatment of enteritis associated with coccidiosis. Numerous additional drugs and drug combinations have been used with some success. Among the newer drugs, ponazuril appears to be effective, according to published research and user testimonials.
Control and Prevention
In addition to treatment, appropriate sanitation is helpful in preventing spread of coccidiosis in kennels and catteries. Oocysts sporulate quickly once in the environment; daily removal of feces can aid in the prevention of coccidiosis. After they are infective, oocysts are resistant to most commonly used disinfectants. Infective oocysts can survive for many months in the environment. Disinfectants containing high concentrations of ammonia can destroy oocysts, but harmful odors and the necessity of removing animals from runs or cages during treatment limit their use. Steam and pressure washing may help to dislodge feces from kennel and cage surfaces. Painting or sealing kennel floors will help prevent adherence of feces to these surfaces and will aid in cleaning. Treatment of all in-contact animals may also be beneficial in controlling coccidiosis in kennels.