Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: March 16, 2005
Publication Date: N/A
Interpretive Summary: Mycobacterium avium subsp. paratuberculosis (Map), the causative agent of Johne’s disease in cattle, is responsible for a $250 million annual loss to the US dairy industry. Such losses can be minimized by early detection and culling of infected cattle and by preventing the oral-fecal routes of transmission, as the pathogen survives in feces for longer than a year. Early detection of infection is difficult since the fecal culture methods, the current gold standard, can take as long as 4 to 6 months to confirm the presence of pathogens. Lack of rapid and sensitive methods hitherto hindered the efforts to monitor the environmental fate and transfer of Map from animal manure to crops. We have developed sensitive real-time sequence detection (qPCR) methods (SYBR Green and TaqMan) for the detection of Map. These methods take only few hours to identify Map as compared to 6 months by culture methods. Map cells can be quantified directly from growth media by using the SYBR Green assay. This method is sensitive to detect a fractional equivalent of a Map cell. Both SYBR Green and TaqMan assays are highly specific for the detection of Map. They did not detect other mycobacteria that are likely to be present in environmental samples. The rapid qPCR methods developed represent significant contribution for sensitive detection of environmental strains of Map and are suitable for monitoring the fate and transfer of Map in dairy and agricultural environments.