The Porcine Reproductive and Respiratory Syndrome (PRRS) virus has plagued the U.S. since 1987. Infected pigs have trouble reproducing and gaining weight, and they have a high mortality rate. There’s no vaccine, and losses in North America total around $660 million annually.

That all could change after researchers from the University of Missouri, Kansas State University and Genus, plc have successfully bred pigs that aren’t harmed by PRRS.

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