We are not afraid of pestivirus

GM pigs resistant to classical plague have been created in China

Sergey Vasiliev, Naked Science

Unlike human, classical swine fever is a viral disease caused by the yellow fever-related flavivirus Pestivirus. The disease is contagious and ends in death in 80-100 percent of cases. In the developed countries of North America and Western Europe, it is almost eradicated, and in Russia it is also not so common. However, outbreaks of swine fever continue in China and some other regions. The disease causes enormous damage to agriculture – it is not for nothing that the swine plague now and then becomes the subject of interstate quarantines and world news.

To prevent epidemics, manufacturers are forced to carry out expensive measures, including disinfection and vaccination. However, the team of Hongsheng Ouyang from Jilin University in China managed to get pigs that do without it: they are resistant to the classical plague and pass this ability by inheritance. Scientists write about this in an article published in the journal PLOS Pathogens (Xie et al., Genetically modified pigs are protected from classical swine fever virus).

The authors combined two different genetic modification technologies – CRISPR/Cas9 and RNA interference. The first made it possible to make a point incision in the pig DNA strictly in the right place, on the Rosa26 promoter site, where a small additional fragment was then inserted. Short "hairpins" of RNA, which are synthesized by the cell from this additional site, make it immune to the virus of classical swine fever.

Early embryos with a modified genome were transplanted to female pigs, who soon gave birth to GM piglets. To assess their resistance to the virus, scientists divided the animals into two groups, which included three GM pigs, three normal (control) and one infectious. Soon all the animals of the control group died, but the modified ones, although they caught the virus, survived the disease with almost no symptoms.

Scientists have shown that this resistance is transmitted to offspring – at least one next generation. The authors hope that soon the method will be deployed to an industrial scale and it will make it possible to massively introduce the "resistance gene" into the populations of breeding pigs. And in the future, it may be possible to adapt the approach for other diseases and animals.

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