Agency: Agricultural Research Service Date Filed: March 1, 1996 Abstract: The invention is a way to distinguish RespPRRSr vaccine from wild strains of porcine reproductive and respiratory syndrome virus (PRRSV) and to distinguish the virulent field strains of PRRSV from one another. The invention uses a segment of the viral genome which differs sufficiently among various strains for a sensitive, reliable and rapid assay of PRRSV suitable for large-scale heard screening. Inventors: Ronald D. Wesley Ann C. Vorwald USDA, ARS, NADC USDA, ARS, NADC Virology Swine Research Virology Swine Research Ames, IA 50011 Ames, IA 50011 (515) 239-8254 (515) 239-8234 (515) 239-8458 --fax (515) 239-8458 -- fax Deborah F. Clouser Kelly M. Lager USDA, ARS, NADC USDA, ARS, NADC Virology Swine Research Virology Swine Research Ames, IA 50011 Ames, IA 50011 (515) 239-8465 (515) 239-8371 (515) 239-8458 -- fax (515) 239-8458 -- fax Industry Keywords: pig, pregnant sows, in vitro, in vivo, swine, veterinary, disease, diagnostic, animal health animal health