Many are species specific and exist only on the dog.
Intestinal parasitism exists in all ages of dogs with the greatest frequency in puppies.
Types and incidence of parasitism varies with geographic regions. This article concerns itself with canine GI parasites of North America. Most parasites are diagnosed by a microscopic fecal examination using various chemicals to help concentrate the population of parasite eggs. Some parasites are visible to the naked eye although, they are not consistently shed into the feces. Eimeria and Isospora are the two most common coccidia of the dog.