Detection of Mycobacterium paratuberculosis in Bulk Tank Milk Filters

Situation or problem: Paratuberculosis (Johnes disease) is a costly infectious intestinal disease of cattle caused by Mycobacterium paratuberculosis (MAP). The disease affects ruminants worldwide, causing weight loss and decreased milk production in affected animals. The United States Animal Health Association (USAHA) approved a resolution (#12) in October, 2006 stating "The United States Animal Health Association (USAHA) recommends that the United States Department of Agriculture (USDA), Agricultural Research Services (ARS) and the research community have a greater focus on development of quantitative based tests for detecting Mycobacterium avium paratuberculosis (MAP) in bulk tank milk." Purpose: The overall goal of this project is to develop a sensitive diagnostic test, using real-time PCR, to determine the presence and magnitude of MAP infection in dairy herds using pipeline in-line milk filters as a surrogate composite test sample. Towards this goal, Tetracore has developed and produced the only quantitative real-time PCR Johnes Disease test available in the North American marketplace. This assay has been demonstrated to be significantly more sensitive than both ELISA and IS900 PCR testing, detecting the presence of less than 30 organisms/gram of fecal material in several hours rather than the weeks required for MAP culture of samples. This assay will be applied to the detection of MAP organisms in milk filters, and protocols will be developed specific for this test sample.