Diverticulitis with rupture and fatal peritonitis in a Sumatran orangutan (Pongo pygmaeus)

A 30-year-old male Sumatran orangutan (Pongo pygmaeus) presented with signs of depression, lethargy, anorexia, and diarrhea that progressed to acute c olic. Exploratory laparotomy revealed fibrinopurulent peritonitis and 50 cm of devitalized small intestine. The surgically resected small intestine co ntained several mucosal diverticula along the mesenteric attachment; one ha d ruptured, resulting in peritonitis. Fifteen days after surgery, the orang utan's abdominal incision dehisced. Repeated laparotomy revealed dehiscence of the distal intestinal anastomosis site, as well as extensive adhesions and purulent exudate. The defect was repaired, and the abdomen was extensiv ely irrigated and closed, but the animal died within 24 hours. To our knowl edge, this is the first report of diverticulitis in a great ape. Diverticul osis should be considered in the differential diagnosis for great apes that present with signs of depression, lethargy, anorexia, and/or diarrhea.