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Johne's Disease - New Test Validation

Investigators
Archambault, Marie
Institutions
Animal Health Laboratory
Start date
2001
End date
2004
Objective
The overall objective of this project is to provide rapid and accurate diagnostic tests to identify cattle infected with M. paratuberculosis in Ontario. The first goal is to set up and validate the BACTEC system and the IDEXX PCR to identify M. paratuberculosis in bovine feces. The last objective is to combine both procedures to reduce the turnaround time.

Expected Impact of Project Outcomes on Food Safety in Ontario:
This new testing methodology is now providing Ontario producers with rapid and accurate diagnostic tests for control programs for Johne's disease. In the past, fecal samples were sent to the USA for Johne's culture. Ontario now has the laboratory capability to culture M. paratuberculosis from diagnostic samples. Removal of infected animals will help eliminate the shedding of this pathogen into the environment and reduce the risk of human infection by M. paratuberculosis through milk, meat and water transfer. Control of M. paratuberculosis will also assist with domestic and international sales of cattle, especially to prominent US dairy states with active Johne's control programs.

More information
Paratuberculosis (Johne's disease) is an infectious disease of ruminants caused by Mycobacterium avium spp paratuberculosis (M. paratuberculosis) considered to be a serious infectious disease currently plaguing the world's cattle industry. In the terminal stages of the disease, affected cows develop diarrhea and wasting. More importantly, most infected cows are asymptomatic but some will shed the organism in colostrum and milk as well as contaminate the environment by fecal shedding. In addition to animal health, a significant concern to consumers and to Ontario dairy producers is the controversial evidence that M. paratuberculosis may be causally linked with Crohn's disease of humans.

Control of Johne's disease has been complicated by the absence of rapid, cost-effective and sensitive individual or herd tests. Prevention would be much improved if diagnostic tests were able to determine the status of sub-clinical cows. The BACTEC culture system offers speed benefits over conventional culture. Also, IDEXX Laboratories recently launched an improved Johne's DNA probe for PCR.

For more information, please visit the Ontario Ministry of Agriculture, Food & Rural Affairs (OMAFRA) Food Safety Research Program.

Funding Source
Ontario Min. of Agriculture Food and Rural Affairs
Project number
SF6002
Categories
Bacterial Pathogens