Coccidia are single-celled parasitic organisms that can live in dogs, cats, livestock and sometimes humans. In many cases, a coccidia infestation is considered nonparasitic or nonclinical, as there are no symptoms and no adverse affects for the host. In certain individuals, however, the infection can cause serious symptoms and even death.
Coccidia in Dogs
Coccidia oocysts, similar to eggs, are shed in the feces of an infected animal. If another dog ingests the matter, the sporozoites are released within him. These sporozoites infest the lining of the intestine, reproduce and continue the cycle. Outside of the body, the oocysts can survive for more than a year. They're able to withstand temperatures between 22 degrees below zero Fahrenheit and 104 degrees Fahrenheit, making them extremely hardy. The coccidia life cycle requires only one host.
While up to 38 percent of dogs in North America may be affected with coccidia, in most cases the infection is harmless. Your veterinarian may find coccidia oocysts in a stool sample of your dog -- but, unless the organisms are causing serious harm, the infection is generally not treated. In high-risk areas, more than 80 percent of animals may be infected, though only 5 percent to 10 percent have any clinical signs of disease.
Populations at Risk
Certain dogs are at higher risk for a pathological or clinical infection of coccidia. Dogs who have been stressed by weaning, overcrowding, poor sanitation, shipping, poor weather or poor nutrition are at higher risk. Very young or old dogs and those with compromised immune systems are also at greater risk. Pathological coccidia is more likely to spread in kennels, especially if the dogs have transferred owners in the last 21 days.
Symptoms of Pathology
A number of symptoms reveal that coccidia has become pathological, ranging from mild to severe. Diarrhea, vomiting and slightly bloody or watery feces are common in milder cases. More severe cases may include weight loss and large amounts of blood in the stool. Rare cases may have neurological symptoms like muscle tremors or convulsions. Dogs who recover generally develop at least partial immunity to the condition.