Prevalence of Mycobacterium Avium Paratuberculosis in Lymph Nodes & on Hides & Carcasses from Cull Cow & Fed Cattle Slaughter Plants

Findings: Crohn�s disease is a human disease that shares similar etiology to Johne�s disease in cattle. The causative agent for Johne�s disease is the bacterium Mycobacterium avium subspecies paratuberculosis (Map), and some clinical research reports that this bacterium may be associated with Crohn�s 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.