Abstract
This chapter reviews a group of diseases of swine resulting from infection with anaerobic intestinal spirochetes of the genus Brachyspira. These include swine dysentery (SD), a severe mucohemorrhagic colitis caused by infection with strongly hemolytic Brachyspira species, as well as milder forms of brachyspiral colitis caused by weakly hemolytic Brachyspira species. SD occurs mainly in grower and finisher pigs and less frequently in weaner pigs. Brachyspiral colitis is an umbrella term used to describe diarrhea and colitis in pigs infected with one or more pathogenic Brachyspira spp. Brachyspira pilosicoli colonizes human beings who are usually either immunocompromised or live in developing communities where hygiene is poor and fecal contamination of water supplies may occur. Porcine intestinal spirochetosis or porcine colonic spirochetosis has been reported in most pig‐producing countries. Transmission occurs by the fecal‐oral route, and infection may be introduced into naïve herds by carrier pigs.