Determine the prevalence of Mycobacterium avium subspecies paratuberculosis in cattle feces or
ileocecal lymph nodes, on cattle hides, and on pre-evisceration and post-intervention
carcasses in cull cow and fed cattle at slaughter plants in the Eastern, Midwestern and
Western regions of the United States.
Findings: Crohnï¿½s disease is a human disease that shares similar etiology to Johneï¿½s disease in cattle. The causative agent for Johneï¿½s disease is the bacterium Mycobacterium avium subspecies paratuberculosis (Map), and some clinical research reports that this bacterium may be associated with Crohnï¿½s disease. Beef consumption may be a potential route of Map transmission to humans, but baseline prevalence of Map in U.S. beef is unknown. In this study examining over 3300 samples from more than 600 animals collected at U.S. beef processing plants, Map was detected in only 0.4 % of the younger fed-cattle and viable Map was not detected on any beef carcasses from these animals. Based on this research, beef from younger animals (less than 3 years of age) does not appear to be a significant source for Map transmission to humans. However, Map was detected in 34.2 % of older cattle, but viable Map was detected on only 0.6% of beef carcasses from these animals. Based on this research, it would appear that Map is widely distributed in older cattle in the U.S., but current interventions implemented by the beef processors appear to minimize possible transmission of this bacterium to humans.