Since the Porcine Reproductive and Respiratory Syndrome (PRRS) virus first appeared in the U.S. in 1987, it has cost the U.S. pork industry roughly $10 billion.  PRRS causes severe pneumonia or respiratory problems in newborn piglets and young pigs, resulting in a 20 percent to 80 percent mortality rate, and reproductive failure in sows. 

Now, teams of researchers from the University of Missouri and Kansas State University have collaborated with experts from Genus plc to develop the first generation of pigs resistant to PRRS.

Randall Prather, a distinguished professor of animal sciences at the University of Missouri and one of the study's researchers, explained the science behind PRRS itself.

“Once inside the pigs, PRRS needs some help to spread; it gets that help from a protein called CD163,” he explained. “We were able to breed a litter of pigs that do not produce this protein, and as a result, the virus doesn’t spread. When we exposed the pigs to PRRS, they did not get sick and continued to gain weight normally.”

Raymond "Bob" Rowland, professor of diagnostic medicine and pathobiology at Kansas State University and another researcher on the project, praised the discovery, stressing that it not only will significantly improve animal well-bring but will also save hundreds of millions of dollars each year. In the U.S. alone, PRRS leads to annual losses of approximately $664 million.

"In the decades that we have had the PRRS virus, we have looked at vaccines, diagnostics and other strategies and we have never been able to eliminate the disease," Rowland said. "This is the first time that we have established the potential to eliminate this devastating disease."

The collaborative research appears in Nature Biotechnology in the article, "Gene-edited pigs are protected from porcine reproductive and respiratory syndrome virus."

“The demonstration of genetic resistance to the PRRS virus by gene editing is a potential game changer for the pork industry,” said Jonathan Lightner, Chief Scientific Officer and Head of R&D of Genus plc. “There are several critical challenges ahead as we develop and commercialize this technology; however, the promise is clear, and Genus is committed to developing its potential. Genus is dedicated to the responsible exploration of new innovations that benefit the well-being of animals, farmers, and ultimately consumers.”

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