Scientists have employed advanced genome editing techniques to produce pigs potentially resilient from porcine reproductive and respiratory syndrome (PRRS) – an infection costing the swine industry billions of pounds each year.
The research team at the University of Edinburgh’s Roslin Institute, in collaboration with Genus and the Pirbright Institute, used a gene-editing tool called CRISPR/Cas9 to cut out a small section of the CD163 gene in the pigs’ DNA code.
Laboratory tests of cells from the pigs with the modified CD163 gene have confirmed this change in DNA blocks the PRRS virus from being able to cause infection.
One step further, tests have revealed cells from the pigs are completely resistant to infection with both major subtypes of the virus that causes the disease.
The animals are otherwise healthy and the change – introduced using gene-editing technology – should not affect their ability to fight off other infections, the researchers say.
In the latest study, only the section of CD163 that interacts with the PRRS virus was removed, with the molecule appearing to retain its other functions.
The study, published in the journal Plos Pathogens, was funded by the Biotechnology and Biological Sciences Research Council’s Animal Health Research Club and biotechnology company Genus.
The next stage in the research will be to test whether the pigs are resistant to infection when exposed to the virus.
PRRS is endemic in most pig-producing countries. Vaccines have mostly failed to stop the spread of the virus, which continues to evolve rapidly.
Consequently, it is said to be one of the greatest challenges facing pig producers today. In Europe alone, the disease is estimated to cost the pig industry more than €1.5 billion each year.