Researchers from the University of Missouri developed pigs resistant to Porcine Reproductive and Respiratory Syndrome (PRRS), an incurable disease that costs farmers in North America over $660 million every year.

PRRS was first discovered in 1987 and has since then led to high mortality rates in pigs, aside from difficulty in gaining weight and reproducing. No vaccine has been developed against PRRS, leading to millions of dollars in losses for farmers in the U.S., although researchers have been trying to determine for years how the virus infected pigs.

Previously, it was believed that PRRS begins after a pig inhales the virus and it attaches to a protein called sialoadhesin which is found on the surface of white blood cells in the lungs. However, when researchers eliminated the protein in test pigs, they found that removing sialoadhesin does not contribute to lower risks of developing PRRS.

Further tests revealed that a protein CD163 helps the PRRS virus spread inside pigs' bodies. The protein's role in the disease's development was proven when University of Missouri researchers decided to develop a breed of pigs that don't produce CD163.

The result?

Pigs exposed to the PRRS virus did not get sick and were able to continue gaining weight normally.

Before this, CD163 was thought to have the ability to remove the virus' coating, which allows it to infect pigs.

By editing the gene responsible for DC163, they were able to prevent the pigs from producing the protein, said Kristin Whitworth from the University of Missouri's Animal Sciences Division. Because pigs who don't produce CD163 will never get sick from PRRS, the discovery of the protein's role will have massive implications for pig farmers in the country, as well as the food industry at large and how other major diseases in other species will be addressed.

Aside from not getting sick with PRRS, those pigs that don't produce CD163 have not shown any deviations in development compared to those that do.

The research is still in its early stages but its results show a lot of promises, prompting the University of Missouri to sign an exclusive licensing deal with Genus plc. If desired results are produced in the development stage, these will signal to Genus plc to initiate all necessary registrations and approvals from governments to facilitate a wider market release.

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