Clostridium perfringens enterotoxemia occurs in dogs of all ages and breeds and occasionally in cats. The syndrome is common and may develop as an acquired or nosocomial infection. In the latter condition, signs are seen during long term hospitalization or following extended boarding.

Gastrointestinal symptoms can be either acute or chronic with signs in chronic cases lasting up to 5 months. Most dogs with acute clostridial enterotoxemia exhibit signs of large bowel diarrhea, as enterotoxin damages the distal small intestine and proximal colon. Fecal mucus, fresh blood, scant stools, tenesrnus and increased frequency of defecation are characteristic. Some dogs may have only mucoid stools while others may present with clinical signs of small bowel diarrhea characterized by large volumes of watery stool. The duration of an acute episode is approximately 3-5 days. Chronic disease may fluctuate occurring every few weeks and lasting for several days. Vomiting may or may not be present and fever is seldom observed.

Enterotoxemia has been identified with con- current diseases such as hemorrhagic gastroenteritis syndrome (HGE), parvovirus enteritis, giardiasis and other causes of inflammatory bowel disease. Such concurrent disease, as well as dietary changes and stress may all predispose to the condition.

Enterotoxigenic Clostridium perfringens strains produce clinical signs in an overgrowth situation. Enterotoxin production exerts its effect locally and directly on the intestinal epithelium causing secretion of protein and electrolyte-rich fluid into the intestinal lumen. Eventual necrosis and sloughing of the mucosal epithelium occurs weakening intestinal peristalsis.

Clostridium perfringens is a normal enteric bacterium found predominantly in a vegetative, non-enterotoxin producing form. Under certain conditions, the organism undergoes enteric sporulation at which stage the enterotoxin is released. The organisms tend to colonize the distal small intestine and upper colon and sporulation is favored in an alkaline environment.

Nutritional changes, alteration of bacterial microflora, decreased local IgA immunity and intestinal epithelial injury may all play a role in initiating the spore forming change in the strains of clostridium that produce this disease.

Studies at Colorado State suggest that this form of enterotoxemia may account for up to 15% of dogs that present with gastrointestinal disease.

Since Clostridium perfringens is a normal intestinal inhabitant, anaerobic fecal cultures for the organism alone are not diagnostic. Direct smear cytology to identify high numbers of spore forming clostridial organisms serves as a simple rough screening test. Two thin, air dried smears of fecal material can be submitted for Direct Smear Cytology, Test Code #5249. The smear is stained and checked for the presence of a high percentage of spore forming clostridial organisms. Spore counts of greater than 5 per high power oil immersion field are considered as suggestive, however, the absence of spores does not rule out the diagnosis. Definitive diagnosis is based on identifying the enterotoxin in the feces. The test requires 3-5 grams of fecal material submitted on ice. Submit as Test Code #16007 Clostridium perfringens Enterotoxin (CLOE).

Most acute cases respond well to fluids and oral antibiotic therapy directed against Clostridium perfringens. Ampicillin, amoxicillin, tylosin, clindamycin or high dose metronidazole therapy have been recommended.

Chronic cases require long term antibiotic use and/or diet manipulation using high fiber content diets. Fiber has been shown to alter colonic bacterial microflora and maintain a more acidic pH. These changes inhibit clostridial spore formation. Soluble fiber supplements such as psyllium can also be used.

Since infection appears to be associated with environmental contamination in nosocomial hospital infections, thorough disinfection is an important control measure. Feeding high fiber diets to hospitalized patients has also been shown to decrease the incidence of this disease.