Supported by FAPESP (Processo 2006/56993-4 e 2008/03229-0)

Marmosets continue to increase in popularity as a pet and also increase the willingness of their owners to pursue advanced medical care. Causes of morbidity and mortality of neonates and infant marmosets are poorly described and the veterinarians are not familiarized with that issue. Identification of causes and the correct treatment of gastrointestinal (GI) diseases in marmosets might represent a challenge for the clinical practice. Diarrhea, weight loss, and failure to grow are common signs of malabsorption/ maldigestion syndrome that can be a common finding of GI disease recognized in children and also young animals. The purpose of this report is to outline the major clinical signs and clinical management of infant marmosets with GI signs. Tree captive infants marmosets a 119 days female common marmoset (Callithrix jacchus), a 95 days female and a 45 days male of black penciled marmoset (Callithrix penicillata) were attended with failure to grow, emaciation, weight loss, intermittent abnormal stool with nearly formed feces to watery diarrhea, pale mucous membranes, and distended abdomen for respectively three and two months, and 45 days of clinical signs. The fecal exam demonstrated fat globules, muscle fibers, starch granules and absence of fecal proteolytic activity in gelatin test. Intestinal parasites evaluation and fecal culture were negative. Image examination showed osteopenia, and homogenous abdomen. The malabsorption/ maldigestion syndrome diagnosis were made and the infants were treated with antibiotic; changed the milk formula; oral vitamins and minerals support, and pancreatic enzymes were added at least two meals daily. After two days the feces consistency had improved and the distended abdomen had decreased. The two penciled marmoset followed 15 days to two months had general clinical improvement and the enzyme supplementation was reduced to once a day to totally withdraw. The common marmoset had transitory clinical improved for 15 days and then GI signs restarted with weight loss to cachexia and finally euthanasia in extremis. The differential causes for GI syndromes such as lactose intolerance, bacterial overgrowth, pancreatic insufficiency were discussed. In conclusion the report exemplified the clinical diagnosis of transitory malabsorption/ maldigestion syndrome in marmoset and possible treatment for infant marmosets.