January 2016: Will PIC really make PRRS a problem of the past?

I continue where I left off last time by returning to the topic of PRRS. No sooner had I discussed the “damage” a cure for PRRS could do to the US pig sector, than Kansas State University, the University of Missouri and Genus plc (the owner of PIC) announced they’d done just that.

It turns out that there’s a naturally occurring protein in pigs, CD163, that plays a vital role in the spread of the PRRS virus when it gets into the pig. The researchers suggested that if you could stop the animal from producing CD163, you could protect it from PRRS – and they were right!

“We were able to breed a litter of pigs that don’t produce this protein, and as a result, the virus doesn’t spread,” Professor Randall Prather of the University of Missouri reported. “When we exposed the pigs to PRRS, they didn’t get sick and continued to gain weight normally.”

Now, this is where the story gets a bit complicated, as researcher Kristin Whitworth, also from the University of Missouri, explained: “We edited the gene that makes the CD163 protein so the pigs could no longer produce it. We then infected these pigs and control pigs; the pigs without CD163 never got sick.

“This discovery could have enormous implications for pig producers and the food industry throughout the world,” she added.

Now that might just be the understatement of the decade – and it’s something only a scientist could say! We’re not talking about a new vaccine here that can be trialled and judged safe, the process that’s being proposed involves genetic manipulation that many will find unacceptable.

Just consider the challenges ahead if the pig sector needs to go the UK’s retailers and try and explain that they want to change to pigs that have, quite literally, been genetically modified.

As the early-stage results of this research have proved so promising, the University of Missouri has signed an exclusive global licensing deal for potential future commercialisation of PRRS resistant pigs with Genus plc. If the development stage is successful, Genus will seek any necessary approvals and registration from governments before a wider market release.

And this could also prove to be a way to tackle other important production diseases in pigs in the future.
So, to come full circle, the researchers that have produced the PRRS-resistant pigs estimate that the disease costs North American farmers alone more than £440 million annually in lost production. But as I discussed on this page last month, the economics of supply and demand mean that this lost production is also an important factor in supporting prices.

Don’t get me wrong, healthier pigs must always be the aim – and from a sustainability point of view it will give the sector a tremendous boost – but without an accompanying increase in pork consumption, it will also mean a huge contraction in the number of pig producers.

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About The Author

Graeme Kirk has been editor of Pig World since March 2013. Born into a farming family in South-west Scotland, he’s spent his career in agricultural journalism.