Evaluation of environmental sampling to determine distribution and herd infection status for Mycobacterium avium subspecies paratuberculosis

Johne's Disease (JD), or paratuberculosis, is a chronic, progressive disease of ruminants caused by the effects of Mycobacterium avium subspecies paratuberculosis (MAP) on the gastrointestinal tract. It is transmitted primarily through a fecal-oral route, especially from manure and environmental contamination by infected adult cattle, and young cattle are most susceptible (Sweeney, 1996). The disease is manifect in adult cattle, leading to economic losses associated with decreased milk production, early culling, and decrease in carcass weight due to wasting. Control of this disease has become a focus of programs in several countries (Kennedy and Benedictus, 2001; Sockett, 1996)