Equine colitis "X", still an enigma?

Colitis "X" is a sporadic diarrheal disease of horses with clinical signs of dehydration, electrolyte imbalances and "shock"-like features. Macroscopic and microscopic findings include signs of disseminated intravascular coagulation, necrosis of colonic mucosa and presence of large numbers of bacteria in the devitalized parts of the intestine. Recently published work suggests that the causative agent may be Clostridium perfringens, Type A, but the bacteria are recoverable only in the preliminary stages of the disease. Excess protein and lack of cellulose content in the diet is thought to be the trigger for the multiplication of the clostridial organisms. The pathological findings are pathognomonic, but clinically, a number of differential diagnoses have to be considered, such as intestinal accidents, salmonellosis, heavy metal intoxication and occlusive verminous arteritis.