Acquired megacolon can be due to
Acquired megacolon may occur at any age as a result of Chagas disease (Trypanosoma cruzi), obstruction by a neoplasm or inflammatory stricture, toxic megacolon complicating ulcerative colitis, visceral myopathy, or in association with functional psychosomatic disorders (poor toilet training during infancy). Ref : Bailey and Love 26e pg: 1177
Leishmaniasis
Typhoid
Chagas disease
Amoebiasis
Gastrointestinal tract