A team of University of Missouri, Kansas State University and Genus, plc, researchers has bred pigs that are resistant to Porcine Reproductive and Respiratory Syndrome (PRRS) and the early-stage results of this research are promising.
PRRS was first detected in the U.S. in 1987. It has plagued U.S. pig farmers since and costs the industry more than $660 million annually.
“Once inside the pigs, PRRS needs some help to spread; it gets that help from a protein called CD163,” said Randall Prather, distinguished professor of animal sciences in the U. of Missouri College of Agriculture, Food and Natural Resources. “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.”
“It’s certainly an encouraging sign that we might be able to confer some innate genetic resistance to infection, but a lot has to happen between now and then,” said Iowa Pork Producers Association SE Region Director Mike Paustian, a hog farmer from Walcott who also holds a doctorate in microbiology. “I think we’re a long ways from bringing production animals to market on this.”
Pigs that contract the disease have extreme difficulty reproducing, don’t gain weight and have a high mortality rate. To date, no vaccine has been effective.
“It’s a very exciting development in that this is the first time where an intervention for PRRS completely prevented infection when PRRS-naïve pigs were experimentally challenged with the PRRS virus and there was no evidence that the pig was infected with PRRS,” said Dr. Chris Rademacher, Iowa State University Extension swine veterinarian.
The University of Missouri has signed an exclusive global licensing deal for potential future commercialization of virus-resistant pigs with Genus, plc. If the development stage is successful, the commercial partner will seek any necessary approvals and registration from governments before a wider market release.
“The demonstration of genetic resistance to the PRRS virus by gene editing is a potential game changer for the pork industry,” said Jonathan Lightner, Genus chief scientific officer and research and development head. “There are several critical challenges ahead as we develop and commercialize this technology.”
“At the end of our study, we had been able to make pigs that are resistant to an incurable, untreatable disease,” said Kevin Wells, co-author of the study and assistant professor of animal sciences at MU. “This discovery could save the swine industry hundreds of millions of dollars every year. It also could have an impact on how we address other substantial diseases in other species.”
“The technology, while promising, is at least five years and probably longer away from becoming a reality in commercial swine production,” Rademacher added.
Genus plc, the U.S. Department of Agriculture and University of Missouri’s Food for the 21st Century Program provided funds for the research.