CLINICAL AND PATHOLOGIC PRESENTATIONS OF YERSINIOSIS IN VARIOUS NONDOMESTIC SPECIES: AN INVESTIGATION OF YERSINIA PSEUDOTUBERCULOSIS OUTBREAKS FROM FOUR NORTH AMERICAN ZOOLOGICAL INSTITUTIONS

Yersiniosis due to <i>Yersinia psuedotuberculosis</i> can be associated with high morbidity and mortality in various species and has been a cosmopolitan management challenge in zoological institutions. This gram-negative, environmental bacterium thrives in cold, wet conditions and poses a risk to zoo species. Outbreaks can be costly and impact conservation efforts through loss of threatened and endangered species. Antemortem or clinical diagnosis can be challenging due to intermittent fecal shedding and nonspecific clinical signs. This case series describes common clinical presentations, typical postmortem findings, and response to treatment and prophylaxis at four North American zoological institutions. In total, five outbreaks occurred at four institutions during the winter months from 2013 to 2021. Artiodactyls were by far the most common species involved, and clinical signs included separation from the herd, lethargy, diarrhea, and unexpected death. Other species affected in these outbreaks included cheetahs (<i>Acinonyx jubatus</i>), a great-tailed grackle (<i>Quiscalus mexicanus</i>), a rainbow lorikeet (<i>Trichoglossus moluccanus</i>), and a squirrel monkey (<i>Saimiri sciureus</i>). Necrotizing enteritis with sepsis and pneumonia were common postmortem findings. Mortality rates were originally 76.7%, and herd prophylaxis with a third-generation cephalosporin reduced these rates. These data describe the observational and diagnostic tools to aid in timely diagnosis of a <i>Yersinia</i> outbreak across taxa. Aggressive treatment or prophylaxis were shown to improve survival rates.