US achieves PRRS-resistant pigs through gene editing

Porcine Reproductive and Respiratory Syndrome (PRRS) virus was first detected in the US in 1987. Pigs that contract the disease have extreme difficulty reproducing, do not gain weight, and have a high mortality rate. The disease costs American ranchers $660 million a year. A team of researchers from the University of Missouri and Kansas State University have bred pigs that are not affected by the disease. The PRRS virus, once inside pigs, needs help to spread. It gets that help from a protein called CD163. The researchers bred a litter of pigs that did not produce that protein, and as a result, the virus did not spread. They found that when the pigs were exposed to PRRS, they did not become ill and continued to gain weight normally. The researchers worked to prevent the pigs from not producing CD163. To do this, they edited the gene that produces the CD163 protein, so that the pigs could no longer produce it (gene editing does not mean inserting a new ...