Incidence of spontaneous cholecystolithiasis in non-human primates is low. As animal models for gallstone formation, potential correlations between diets high in polyunsaturated fats and low in cholesterol, leading to gallstone formation, have been seen in primates.1,3 Additionally, review of cholecystolithiasis in both humans and non-human primates shows a predilection towards increased lithogenicity with increased age, pregnancy, and in females.2,4 In this case, a 27-year-old female mandrill (Mandrillus sphinx) had repeated occurrences of cholecystolithiasis. Different treatments were attempted over a 4-year period, including medical management with ursodiol and surgery. Ursodiol resulted in complete resolution of the first incidence of cholecystolithiasis, while the second and subsequent bouts of cholecytolithiasis were only partially resolved. Evaluation of the animal’s diet yielded no correlations to stone formation, and cholecystolithiasis has not been found in three other mandrills maintained on the same diet at the facility. The animal was treated successfully with a surgical cholecystectomy through a superior midline celiotomy, after medical management was no longer effective. The animal recovered without complication. Subsequent analysis of the cholecystoliths revealed a mixture of cholesterol, biliverdin, and bilirubin. The animal died 4 months later due to unrelated causes and evaluation of the cholecystectomy site showed normal healing and no surgical complications.
The authors would like to thank the veterinarians, technicians, and veterinary students who assisted in this case. Further, the authors would like to thank Jan Brigham and Jackie Broder and the rest of the zookeeping staff for their involvement and care of this animal.
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3. Scobey MW, Wolfe MS, Rudel LL. Age- and dietary fat-related effects on biliary lipids and cholesterol gallstone formation in African green monkeys. J Nutr. 1995;122:917–923.
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