By Sara Brown and Ben Potter
A research breakthrough could stop a deadly porcine disease
The Porcine Reproductive and Respiratory Syndrome (PRRS) virus has plagued the U.S. pork industry since 1987. Infected pigs have trouble reproducing and gaining weight and 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 (MU), Kansas State University (KSU) and Genus plc have successfully bred pigs that aren’t harmed by PRRS.
“Once inside the pigs, PRRS needs some help to spread,” explains Randall Prather, MU professor of animal sciences. “It gets that help from a protein called CD163. 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.”
Prather’s laboratory developed the pigs and KSU’s Large Animal Research Center laboratory tested for the PRRS virus infection, led by Raymond “Bob” Rowland, KSU professor of diagnostic medicine and pathobiology. Numerous undergraduate and graduate students also were involved in the project.
“In the decades we have had the PRRS virus, we have looked at vaccines, diagnostics and other strategies and have never been able to eliminate the disease,” Rowland says. “It is a unique way of tackling viral disease.”
While the pigs that didn’t produce CD163 didn’t get sick, scientists also observed no other changes in their development compared with pigs that produce the protein.
Researchers hope the discovery will have enormous implications for hog producers. Genus plc has the exclusive licensing agreement with the universities and expects it will be at least five years until PRRS-resistant animals are available to farmers.
“There are several critical challenges ahead as we develop and commercialize this technology,” says Jonathan Lightner, head of research and development for Genus plc. “However, the promise is clear, and [we are] committed to developing its potential.”
The researchers’ study was published in the journal Nature Biotechnology in December 2015.