Tyzzer's Disease

Tyzzer's disease is an infectious disease caused by Clostridium piliforme. The most susceptible species are horses, rabbits, and laboratory animals. This chapter discusses etiology, epidemiology, pathogenesis, clinical signs, clinico-pathologic findings, diagnosis, treatment, prevention and control for Tyzzer's disease. A presumptive diagnosis of Tyzzer's disease can be reached based on gross observations. A definitive diagnosis, however, should be based upon the histologic demonstration of hepatic, intestinal, and/or myocardial lesions and the presence of bacteria in the cytoplasm of affected cells. As with the clinical signs and gross lesions, microscopic changes are similar in all the species. Due to the impossibility of cultivating C. piliforme in vitro using conventional cultural methods, antimicrobial susceptibility patterns were determined in embryonated eggs. Penicillin, tetracycline, erythromycin, and streptomycin were effective against this microorganism. Good hygiene may be beneficial for decreasing the likelihood that disease will occur.