It may be a major problem in localized areas during a particular year, followed by one or more years in which incidence is low. Hexamitiasis is caused by a one-celled parasite of the genus Hexamita. Experimentally, the Hexamita of turkeys can be transmitted to young quail, chicks and ducklings, and that of quail and partridges can be transmitted to poults. However, poults cannot be infected with the organism isolated from pigeons. This disease is found primarily in young birds, and outbreaks seldom occur in poults past ten or eleven weeks.
Losses are most severe in birds three to five weeks old.
Apparently, resistance develops rapidly with increasing age, regardless of previous exposure. The primary infection source is droppings from carrier birds. About a third of recovered birds become carriers. Most outbreaks result from a buildup of organisms through several broods of poults, making exposure of the following brood overwhelming. Indirect transmission may result from fecal material carried from one location to another on shoes or equipment.