Electron microscopy of stool samples for the presence of viral particles was negative. Cytotoxicity assay for Clostridium difficile was negative. Tyzzer's disease affects a variety of animal species. Lesions can be detected in the terminal small intestine, large bowel, liver and heart, but in hamsters, major lesions are sometimes confined to the intestinal tract. The long, thin bacilli typical of Clostridium piliforme are difficult to visualize with routine hematoxylin and eosin staining, but can readily be observed following silver impregnation such as Warthin-Starry or Steiner procedures.
Hamsters appear to be highly susceptible to infection, with high morbidity and mortality.
Hepatomegaly with multifocal, random areas of necrosis is considered the most consistent lesion seen at necropsy in hamsters, gerbils, other laboratory rodents, and foals infected with Tyzzer's disease. The Gram negative, intracellular, filamentous bacilli are most readily found in hepatic, intestinal epithelial, or myocardial cells bordering areas of necrosis. Reports of Tyzzer's disease in dogs and cats are relatively rare. Immune status is suspected to play a role in susceptibility to infection. Tyzzer disease in hamsters and gerbils from a pet store supplier.