Infectious Megaenteron of Mice

A diarrheal disease hitherto unknown explosively occurred in a mouse colony of DDY strain, causing death in a great number of sucklings. Two to three-week-old sucklings were most frequently and severely affected, but mice after weaning acquired gradual resistance to the disease as they grew older and no fatal cases were usually observed in these animals. Lactating mothers were sometimes severely affected when they had sick babies. The disease rarely appeared in sucklings younger than 2 weeks of age. In pathological examinations, thickened walls of various degrees were found in either or both of the jejunum and colon. The lesions of the small intestine were characterized by an increased number of the villi, a replacement of the villus cells due to the hyperplasia of the crypt type cells over the epithelium, a formation of the thickened mucosal folds and a paucity or lack of the inflammatory reactions in any layers of the intestinal wall. Characteristic figures of the large intestine were almost the same as those of the small intestine, except that a marked decrease was observed in the number of the goblet cells. A provisional name “megaenteron of mice” was given to the disease.