Brachyspira spp. are slow-growing anaerobic, spirochete bacteria that colonize the large intestine of several animal species, including humans. Pigs are the most frequent carriers of Brachyspira. Rats can also serve as hosts.
There are nine officially named Brachyspira species identified. The most common species of Brachyspira known to cause disease in chickens are B. pilosicoli and B. intermedia; less commonly B. alvinpulli and B. hyodysenteriae. B. suanatina is found in ducks. The diseases associated with infection with Brachyspira are intestinal spirochetosis in chickens, pigs and humans and swine dysentery and mild colitis in pigs.
Transmission: Brachyspira is shed in infected animal feces. When pigs are the host, the pathogen is able to survive for over 7 months in soil mixed with pig feces. When shed in chicken feces, Brachyspira can only survive for hours to maximum 4 days. This is likely due to the acidic nature of chicken feces and dries out fast.