Johne's disease and the practitioner.

Mycobacterium paratuberculosis infections and the disease states resulting in cattle are defined as spectral in nature. There is a spectrum of immunological response which complicates tests based on this. It is recommended that initial diagnosis of suspicious clinical cases be confirmed by direct fecal smears and a serological test such as immunodiffusion. Herd evaluation requires the application of fecal cultures plus immunodiffusion. Control requires rigid management hygiene measures, surveillance of the herd status and post mortem confirmation of salvaged animals.