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(KNOXVILLE, Tenn.) – A team of scientists with the University of Tennessee has developed an accurate and fast diagnostic test for Johne's disease, a contagious, chronic and fatal intestinal disease of ruminants.

Johne's disease (pronounced "yo-knees") occurs worldwide, especially in dairy and beef cattle, sheep, goats, deer, elk, antelope and bison. Animals with Johne's disease generally suffer from persistent diarrhea, weight loss, decreased milk production and eventually mortality.

The USDA estimates that approximately 22 percent of all dairy herds and eight percent of all beef herds in the United States are infected with Johne's, leading to an estimated annual economic loss of more than $200 million to the dairy industry alone. Johne's is considered one of the most economically important ruminant diseases worldwide.

Johne's is particularly difficult to control because animals do not show clinical signs until two or three years or more after the initial infection. Yet, prior to showing symptoms, infected animals can shed contaminated feces and thus infect other members of the herd.

The diagnostic test developed by the Tennessee researchers takes just a couple of hours to perform, as opposed to some other diagnostic tests that require weeks to complete. The new diagnostic test is highly sensitive and specific, detecting more than 95 percent of animals infected with the Johne's disease-causing bacterium Mycobacterium avium subspecies paratuberculosis. Further, the UT test can detect Johne's in young animals before they become contagious and spread the disease.

Dr. C. A. Speer, professor of cellular and molecular immunology and director of the UT Center for Wildlife Health, directs the team's research efforts. The team's research is funded through the USDA and the Tennessee Agricultural Experiment Station.

"We are very excited about presenting this technology to the nation's producers," Speer said. "Present diagnostic tests for Johne's cannot detect early infections and detect only 17 percent to 38 percent of chronic infections."

"That's not very reliable or useful for a producer who wants a disease-free herd. Our diagnostic test is 95 percent accurate, can detect Johne's by testing milk as well as blood samples, and has immediate and practical benefits for producers," said Speer.

Until now no reliable diagnostic tests for Johne's have existed, and effective vaccines or therapeutic treatments for the disease remain elusive.

The UT test for Johne's is announced to producers in the March 25, 2006, issue of Hoard's Dairyman, one of the premier publications for dairy producers. It was first presented to scientists in the September 2005 issue of the journal Foodborne Pathogens and Disease. A second article will appear in the May 2006 issue of Clinical and Vaccine Immunology.

In addition to Speer, other members of the research team include Dr. Shigetoshi Eda, Cathy Scott and Brad Elliott. Collaborators outside the University of Tennessee include Drs. John Bannantine and Ray Waters at the National Animal Disease Center in Ames, Iowa, Dr. Robert Whitlock of the University of Pennsylvania Veterinary School, and Dr. Yasuyuki Mori of Tsukuba, Japan.

Speer said a major veterinary diagnostics company is evaluating the test. He hopes it will be commercially available in six to 12 months.

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Contacts:
Dr. C. A. Speer, (865) 974-0467
Patricia McDaniels, (865) 974-7141, (865) 363-6009