Mycobacterium avium subspecies paratuberculosis

Mycobacterium avium subspecies paratuberculosis (MAP) is an obligate pathogenic bacterium in the genus Mycobacterium. It is often abbreviated M. paratuberculosis or M. avium ssp. paratuberculosis. It is the causative agent of Johne's disease, which affects ruminants such as cattle, and suspected causative agent in human Crohn's disease and rheumatoid arthritis. The type strain is ATCC 19698 (equivalent to CIP 103963 or DSM 44133). MAP causes Johne's disease in cattle and other ruminants. It has long been suspected as a causative agent in Crohn's disease in humans, but studies have been unable to show definite correlation. Recent studies have shown that MAP present in milk can survive pasteurization, which has raised human health concerns due to the widespread nature of MAP in modern dairy herds. MAP survival during pasteurization is dependent on the D72C-value of the strains present and their concentration in milk. It is heat resistant and is capable of sequestering itself inside white blood cells, which may contribute to its persistence in milk. It has also been reported to survive chlorination in municipal water supplies.