Acute gastrointestinal dilation in laboratory rhesus monkeys in the Korea National Primate Research Center

Acute gastrointestinal dilation is a medical condition in which the stomach and intestine become overstretched by excessive gas content. In laboratory monkeys, cases of bloating involving gastrointestinal dilation are rarely seen, and the cause thereof is not clearly defined. Two rhesus monkeys in the Korea National Primate Research Center were found to suffer from acute gastrointestinal dilation. One of the monkeys showed severe gastric bloating after recovering from general anesthesia with isoflurane, where after it died suddenly. During necropsy, severe congestion of the lung was observed. The other monkey showed gastrointestinal dilation and died after treatment. During necropsy, severe dilation of the large intestine was observed. Severe congestion was detected in small and large intestines. Histopathologically, erythrocytes were found to fill the alveoli and alveolar capillaries of the lung. In stomach, epithelial cells were found to be sloughed from the mucosal layer, and erythrocytes were found to fill the blood vessels of the submucosal and mucosal layers. In small and large intestines, epithelial cells were also found to be sloughed from the mucosal layer, and inflammatory cells were found to have infiltrated in the submucosa (only large intestine) and mucosa. Microbiologically, Enterococcus faecalis and the pathogenic Staphylococcus haemolyticus, which do not form gas in the gastrointestinal tract, were detected in the gastrointestinal contents of both monkeys. These results suggest that the cause of the acute gastrointestinal dilation in these monkeys was not infection by gas-forming bacteria, but rather multiple factors such as diet, anesthesia, and excessive water consumption.