Mycobacteria as a group are known for causing diseases such as tuberculosis. The various species of Mycobacteria are relatively comfortable in hopping across host species lines and this includes humans. For that
reason the presence of Mycobacterial infection in pigs and other food animals is treated as a food
safety issue which can lead to carcass condemnations.
Mycobacterial infections in pigs are commonly caused by the Mycobacterium avium (bird) complex
(MAC). Globally, the importance of the MAC infections in humans is rising because of its higher
prevalence and also higher mortality rates particularly in advanced countries. In addition,
treatment of the MAC infections in humans tends to be complicated because of its increasing resistance
to antimicrobial agents. European studies have documented the MAC occurrence in the lymph
nodes, tonsils, diaphragm, meat and other organs. The lesions of MAC can be spotted by meat
inspectors at slaughter and a granulomatous lymphadenitis is common.
In a recent case in Ontario, growing pigs were exposed to Mycobacterium avium when they
consumed a peat moss product that was contaminated with the Mycobacteria avium. The
peat moss had been top dressed on to their feed. Having the carcass condemnations is tough enough.
Finding out that condemnations will continue until the last pigs that consumed the contaminated peat
moss go to market is an even tougher pill to swallow as you wait for the production pipeline to clear.
Take Home Message
Sometimes it can take a long time to “turn the ship”.
Submitted by Marty Misener, DVM
Ref: Hulinova Stromerova N, Faldyna M.Mycobacterium avium complex infection in pigs: A review. Comp Immunol Microbiol Infect Dis. 2018 Apr;57:62-68. doi: 10.1016/j.cimid.2018.06.005.