Johne's disease

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A chronic disease of domestic animals, especially cattle and sheep, caused by the bacterium Mycobacterium paratuberculosis and characterized by persistent diarrhea, gradual loss of weight, and general weakness.

Wiktionary

1. n. A chronic, contagious and often fatal disease of cattle, sheep and goats, caused by the intestinal bacterium Mycobacterium paratuberculosis, characterized by inflammation of the mucous membranes of the gastrointestinal tract