Pathological Changes in Captive Monkeys with Spontaneous Yersiniosis due to Infection by Yersinia enterocolitica serovar O8

SummaryAn outbreak of fatal yersiniosis due to infection with Yersinia enterocolitica serovar O8 is documented in two species of captive monkey. Five of 50 squirrel monkeys (Saimiri sciureus) and one of two agile gibbons (Hylobates agilis) died following several days of diarrhoea. Necropsy examination revealed necrotizing enterocolitis and multifocal necrosis or abscesses in various organs. Microscopically, these lesions comprised multifocal necrosis with bacterial colonies, neutrophils and accumulation of nuclear debris. Occasional lesions included macrophages and abscess formation. Immunohistochemically, the bacteria were identified as Y. enterocolitica O8. In addition, Y. enterocolitica serotype O8 was isolated from animal organs in pure culture. This is the first report of fatal cases of infection with Y. enterocolitica serovar O8 in animals.