Paratuberculosis (Johne's Disease)
Johne’s (pronounced “Yoh-nees”) disease is a chronic, contagious enteritis characterized in cattle by persistent diarrhea, progressive weight loss, debilitation, and eventually death. It is caused by the bacteria Mycobacterium paratuberculosis, also known as Mycobacterium avium subsp paratuberculosis, is believed capable of infecting and causing disease in all other ruminants (e.g., sheep, goats, llamas, deer) and in captive and free-ranging wildlife.
M paratuberculosis is excreted in large numbers in feces of infected animals and in lower numbers in colostrum and milk. It is resistant to environmental factors and can survive on pasture for greater than one year; survival in water is longer than in soil. Infection is acquired early in life, but clinical signs rarely develop in cattle less than two years old, because progression to clinical disease occurs slowly.