Survival of pathogenic intestinal spirochetes kept in pure cultures and in pig feces held at four different temperatures.

Porcine colonic spirochetosis (PCS) caused by Brachyspira pilosicolihas been identified as a contributing cause of diarrhea and reduced performance of growing pigs in all major swine producing countries. The current view that transmission of PCS occurs through contamination of the environment by acutely or persistently infected pigs is based on the assumption that the spirochetes remain viable in the environment. The purpose of this study was to compare the viability of Brachyspira pilosicolikept in pure culture or mixed with fecesat four different temperatures over time with that of Brachyspirahyodysenteriae. The results of the present study indicated that Brachyspira pilosicolisurvived significantly longer than Brachyspirahyodysenteriae in pure cultures held at 24°C and 37°C, and at all temperatures in spiked fecal materials. Pure cultures of Brachyspira pilosicolisurvived at least 63 days at -70°C, seven days at 4°C, 14 to 28 days at 24°C and seven to 28 days at 37°C. There was significant differences in the survival of the 2 species of spirochetes when mixed with feces. At -70°C, Brachyspira pilosicoliand Brachyspirahyodysenteriae survived respectively an average of 21 and 3 days, and at 4°C 12,25 and 4,25 days. Viability was reduced to one to seven days at 24°C and one to three days at 37°C for Brachyspira pilosicoliand < five days at 24°C and < one day at 37°C for Brachyspirahyodysenteriae. Information on the survival of Brachyspira pilosicolioutside the pig’s body provides a basis to improve strategies for PCS control.