New Tests Quickly Diagnose Bluetongue, Related Diseases

New laboratory tests will allow scientists, regulators and livestock producers to quickly identify animals with bluetongue or epizootic hemorrhagic disease (EHD).

ARS scientists in Laramie, Wyo., have developed the first single genetic test that distinguishes all five types of the virus that causes bluetongue in the U.S. They’ve also developed rapid tests that distinguish bluetongue from EHD.

Bluetongue, so named because it can cause a loss of oxygen and a blue tinge to the tongue, affects sheep, goats, deer, elk and antelope. Cattle can carry the virus, usually without becoming ill. Worldwide, there are 24 strains of bluetongue virus. Countries without bluetongue strictly regulate import and export of livestock and related products, costing U.S. producers about $125 million annually.

Previous tests were not always definitive, requiring additional testing. The new test, developed by ARS microbiologist William C. Wilson, reduces the time it takes to identify the virus type from several days to a single day. All official bluetongue testing in the U.S. is performed at the USDA’s National Veterinary Service Laboratory in Ames, Iowa, and the lab has incorporated Wilson’s test into its procedures.

Wilson and ARS microbiologist James O. Mecham also developed tests that identify the two types of EHD present in the U.S. and distinguish them from bluetongue viruses. Both scientists work at ARS’ Arthropod-Borne Animal Diseases Research Laboratory in Laramie.

EHD can cause a bluetongue-like disease in cattle and is often fatal to white-tailed deer. Correctly identifying which virus an animal harbors is important for trade purposes. There is no cure for either bluetongue or EHD.

ARS is USDA's chief scientific research agency. A detailed story on the research appears in the agency's July Agricultural Research magazine and on the Internet at:

http://www.ars.usda.gov/is/AR/archive/jul99/blue0799.htm

Scientific contact: William C. Wilson or James O. Mecham, ARS Arthropod-Borne Animal Diseases Research Laboratory, Laramie, Wyo., phone (307) 766-3600, fax (307) 766-3500, wcwilson@uwyo.edu (Wilson) jmecham@uwyo.edu (Mecham).