MAP was first identified as a pathogen in the late 1800s, when it was determined to be the cause of Johne’s (pronounced YO-nees) disease in cattle. Johne’s disease, sometimes called paratuberculosis or Bovine Johne’s Disease (BJD), is a chronic, fatal, gastrointestinal wasting disease that primarily affects the small intestine of ruminants like cattle, deer, sheep, goats, antelope, bison and even camels!