A product used as a diagnostic agent, analogous to tuberculin but made from Mycobacterium paratuberculosis (the causative organism of Johne disease) grown in a broth medium containing Mycobacterium phlei (timothy hay bacillus); used as an allergen to provoke reactions in infected animals.
[H. A. Johne]
Johne,H. Albert, German physician, 1839-1910.
Johne bacillus - a species causing Johne disease, a chronic enteritis in cattle. Synonym(s): Mycobacterium paratuberculosis
Johne disease - a disease occurring in cattle and sheep, caused by infection with Mycobacterium paratuberculosis. Synonym(s): chronic dysentery of cattle; paratuberculosis
johnin - a diagnostic agent, analogous to tuberculin.
an extract of the culture of Mycobacteriumavium subspecies paratuberculosis used in a cutaneous delayed hypersensitivity test for Johne's disease. A positive test is a thickening and edema at the site of injection 48 hours later.