How quickly and how far it will spread depends on herd management, says Cornell's Rossiter. In future issues we'll look at the current status of diagnostic tests for Johne's, how to prevent Johne's from entering your herd and how to clean up a Johne's problem. Second in a series on Johne's disease. The bacteria multiply very slowly after infection. Fecal shedding of bacteria from infected animals occurs long before clinical disease develops.
Young calves are at the highest risk for contracting the infection.
Clinical signs may take two to 10 years to develop after infection. Clinical symptoms of Johne's include weight loss, diarrhea and bottle jaw. There is no treatment, and there is no cure. It may survive up to a year in manure, cold temperatures and some sources of water. In an infected herd, all manure should be suspected to be contaminated with Johne's-causing M. paratuberculosis organisms.