Two Cases of Suspected Polioencephalomalacia Secondary to Thiamine Deficiency in White-Fronted Marmosets (Callithrix geoffroyi) Exhibiting Concurrent Clinical Signs of Wasting Marmoset Syndrome
Two white-fronted marmosets (Callithrix geoffroyi) with a history of diarrhea and weight loss were presented with acute neurologic abnormalities, primarily consisting of a stuporous mentation and blindness. Initial physical examination and blood test abnormalities in both animals fit the typical description of Wasting Marmoset Syndrome. The first case, a 7-yr-old female, was euthanatized after one week of empirical treatment due to lack of clinical response. Histopathology findings included chronic enterocolitis and a laminar pattern of microgliosis and astrogliosis in the cerebral cortex (considered to be a reactive response to polioencephalomalacia.) The second case, a 13-yr-old male, received treatment with thiamine and steroids after presentation; his neurologic abnormalities resolved within 48 hr. Clinical improvement continued for 3 mo while he was treated with prednisolone, metronidazole, dietary changes, and B vitamins. The animal was euthanatized in March of 2012 due to a rapid decline in condition of unknown etiology; histologically evaluated brain tissue was unremarkable.
Based on these cases, it was theorized that animals exhibiting signs of Wasting Marmoset Syndrome are susceptible to developing clinical thiamine deficiencies. Blood from healthy marmosets is currently being collected for thiamine level evaluation through use of high-performance liquid chromatography (Bio-Center Laboratory, Wichita, KS 67219 USA). Initial results suggest that Callithrix geoffroyi has a thiamine level approximately four times greater than is expected in humans. While further work is needed to establish species specific reference ranges to aide in management of diseased individuals, parenteral vitamin B supplementation should be considered in cases with neurologic impairment or suspected malabsorptive disease.
The authors thank the hospital staff and primate keepers at The Phoenix Zoo for their dedication to the care of these animals. Additionally the authors thank Dr. Donna Iallegio, and Barbara Toddes, Nutrition Director at The Philadelphia Zoo, for their time, knowledge, and willingness to offer nutrition and treatment recommendations during the management of these cases.