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ARS Researchers Develop Quick Test for Costly Pig Virus

By Linda McGraw
August 4, 1998

ARS scientists have developed a genetic test that can tell the difference between a damaging pig virus--the culprit behind Porcine Reproductive and Respiratory Syndrome (PRRS)--and a harmless strain of the virus contained in a vaccine. The test is accurate and takes only two days to report results after the virus is isolated.

PRRS is one of the most costly diseases that pork producers face worldwide. Severe outbreaks of PRRS virus can sometimes occur even in vaccinated herds, making it important to distinguish field strains from vaccine strains of the virus. If an outbreak occurs, it's difficult for laboratory diagnosticians to differentiate between pigs infected with a field strain of PRRS versus pigs that carry the vaccine strain from routine inoculations.

To solve this problem, ARS researchers at the National Animal Disease Center in Ames, Iowa, developed the test, which pinpoints genetic markers in field and vaccine strains. NOBL/Boehringer Ingelheim Laboratories of Sioux Center, Iowa, participated with ARS in a Cooperative Research and Development Agreement to evaluate this diagnostic test. ARS and the company are negotiating an exclusive licensing agreement for the test.

Previously known as mystery pig disease, PRRS causes late-term fetal deaths, abortions and the birth of weak pigs, and severe respiratory disease in young pigs. PRRS virus has been found in 59.4 percent of unvaccinated swine herds tested, according to a 1995 National Animal Health Monitoring System (NAHMS) study of 286 herds from 16 swine producing states.

Scientific contact: William L. Mengeling, ARS-USDA, Virology Swine Research, National Animal Disease Center, P.O. Box 70, Ames, Iowa 50010 Telephone: (515) 239-8254; fax(515) 239-8458. E- mail: