General Information: Brachyspira hyodysenteriae is the causative agent of swine dysentery, which is a severe mucohemorrhagic diarrheal disease of pigs that has economic significance for pork-producing countries. The bacterium can survive for several weeks in cold moist conditions but not under warm dry conditions. It spreads slowly, building up in numbers as the dose rate of the causal agent builds up in the environment. Pigs that recover develop a low immunity and rarely suffer from the disease again. It can be spread by other organisms (flies, mice, birds and dogs) or external mechanical factors; its main habitat is the porcine cecum and colon. It is chemotactically attracted to mucin which it penetrates with a corkscrew-like motility.