August 2018

Signalment (JPC# 1947391): 16-month-old African green monkey (Chlorocebus aethiops sabaeus)

HISTORY: Found semicomatose with a temperature of 94oF.

HISTOPATHOLOGIC DESCRIPTION:  Colon:  Multifocally affecting approximately 20% of the colonic mucosa, there are well-demarcated segmental areas of coagulative and lytic necrosis of the mucosa, ranging in size from 0.5 to 1.5mm, characterized by retention of cellular architecture with loss of differential cellular staining, and/or complete loss of mucosal architecture with replacement by cellular and karryorectic debris, which extends into the submucosa.  Within the affected areas, there are segmental loss of muscularis mucosa, and the adjacent lamina propria and submucosa are markedly expanded by viable and degenerating neutrophils, with fewer lymphocytes and macrophages, edema, fibrin, and hemorrhage.  Areas of necrosis are overlying Peyer’s patches and Peyer’s patches are decreased in size with lymphoid depletion.  Multifocally vessels within the submucosa and adjacent mesenteric adipose tissue have lost, disrupted or necrotic endothelium with occasional occlusion of the lumen by fibrin thrombi with enmeshed neutrophils and lymphocytes;  the tunica media and externa are thickened by fibrin and edema, admixed with neutrophils, lymphocytes, necrotic debris, and large colonies of 1-2um coccobacilli that often extend transmurally thru vessel walls (necrotizing vasculitis).  Multifocally within areas of necrosis there are large (up to 2.5mm wide) colonies of 1-2 um amphophilic coccobacilli that extend into the submucosa.

Liver:  Multifocally and randomly affecting 10% of the parenchyma are well-demarcated, 100-500um areas of lytic necrosis characterized by loss of normal hepatic architecture and replacement  by eosinophilic cellular and karyorrhectic debris, admixed with moderate numbers  of degenerate neutrophils, fibrin, and large  (up to 200 um wide) colonies of 1-2 um amphophilic coccobacilli.  Hepatocytes surrounding areas of necrosis multifocally are hypertrophed, and occasionally dissociated with pale vacuolated cytoplasm (degeneration).  Randomly in the sinusoids are individual large coalescing bacterial colonies accompanied by viable and degenerate neutrophils and macrophages.


  1. Colon: Colitis, necrohemorrhagic, segmental, acute, severe, with vasculitis, thrombosis, and large colonies of coccobacilli, African green monkey (Chlorocebus aethiops sabaeus), non-human primate.
  2. Liver: Hepatitis, necrotizing, random, multifocal to coalescing, moderate, with large colonies of coccobacilli.

ETIOLOGIC DIAGNOSIS: Colonic and hepatic yersiniosis

ETIOLOGY: Yersinia enterocolitica










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  9. Soto E, Griffin M, Verma A, Castillo-Alcala F, Beierschmitt A, Beeler-Marfifi J, et al. An Outbreak of Yersinia enterocolitica in a Captive Colony of African Green Monkeys (Chlorocebus aethiops sabaeus) in the Caribbean. Comp Med. 2013: 63(5): 439-444.

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