Mycobacterium avium subspecies paratuberculosis is a pathogenic bacteria in the genus Mycobacteria. It is often abbreviated MAP, M. paratuberculosis, or M. avium sub. paratuberculosis.

MAP causes Johne's disease in cattle and ruminants, and it has long been suspected as a causative agent in Crohn's disease in humans.

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 is heat resistant and it 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.

Even though MAP is hardy, it is slow growing and "fastidious", which means it is difficult to culture. Many negative studies for MAP presence in living tissue, food, and water have used culture methods to determine whether the bacteria is present. Due to recent advances in our knowledge of the bacterium, some or all of these studies may need to be re-evaluated on the basis of culture methodology.

MAP, like most mycobacteria, is difficult to treat. It is not susceptible to anti-tuberculosis drugs (which can generally kill Mycobacterium tuberculosis), but can only be treated with macrolide antibiotics such as Rifabutin. Treatment regimes can last years.

See also

• zoonose