The bacterium Clostridium perfringens that causes enterotoxemia in dogs is present in the soil as well as in the digestive system of animals. It produces toxins and releases them into the intestines causing the inflammation which is termed enteritis. When these toxins are absorbed, it results in enterotoxemia.
Of the different types of Clostridium perfringens, it is only Type A that affects dogs, causing enterotoxemia. It is also known to cause bloody diarrhea in dogs, but it is rare. It may be responsible for the chronic diarrhea that occurs intermittently in dogs too, even though there’s no proof for this.
Dogs which have intestinal inflammation due to parovirus infection are found to have higher population of Clostridium perfringensin their intestines, but it is not known whether it has any bearing on the disease.