Tyzzer disease in hamsters and gerbils from a pet store supplier

An episode of Tyzzer disease (Bacillus piliformis) developed in hamster and gerbil colonies of a pet store supplier. The incidence of diarrhea and subsequent mortality was high. The only important necropsy findings were cecal distention and mesenteric lymphadenopathy in the hamsters. Histologically, necrotizing typhlitis and hepatitis with associated B piliformis organisms were seen in both species. This case was unusual because the most consistent gross lesion associated with Tyzzer disease--hepatomegaly with multiple pale foci of hepatic necrosis--was not seen. Tyzzer disease is widespread geographically and among species; B piliformis has been reported to cause disease in at least 18 species of animals including hamsters, gerbils, rabbits, guinea pigs, horses, cows, dogs, and cats. Clinical signs of disease are nonspecific, and treatment is difficult because the organism is intracellular, although tetracycline and oxytetracycline reportedly have controlled mortality.