Scientists create pigs resistant to classical swine fever | Gene editing
Pigs resistant to a deadly viral disease have been created by scientists at the Roslin Institute in Edinburgh.
Genetically modified animals remained healthy when exposed to classical swine fever (CSF), a highly contagious and often fatal disease. The virus was eradicated in the UK in 1966, but there have been several outbreaks since and it continues to pose a major threat to pig farming worldwide.
“Classical swine fever is a devastating disease for livestock and farmers, as we saw with the outbreak in the UK 25 years ago,” said Helen Crooke, deputy head of mammalian virology at the Animal and Plant Health Agency (APHA), where the pig trial was carried out. “Hopefully this breakthrough can help strengthen the livestock sector’s resilience to the disease. »
Classical swine fever, also known as swine fever or swine fever, causes fever, skin lesions, convulsions, diarrhea – and often death within 15 days.
In the UK, periodic outbreaks since the 1960s have led to the culling of 75,000 pigs. And in countries like China, Russia and Brazil, where the disease is endemic, classical swine fever is controlled through costly, labor-intensive vaccination programs and international trade restrictions.
Dr Christine Tait-Burkard, group leader at the Roslin Institute, said: “This virus has serious effects on animal welfare and productivity. »
The latest study, the first to demonstrate resistance through gene editing, targeted a gene responsible for producing a protein called DNAJC14. This protein has been shown to play an essential role in the replication of pestiviruses (the family of viruses that includes the CSF) once they enter the cell. Previous studies on cells had shown that changing just a few letters of the DNA code blocked viral replication.
In the latest study, scientists at the Roslin Institute created a line of pigs with the same precise changes to their DNA. Four of the pigs were then exposed to CSF, along with four control pigs, at APHA’s biosecure facility.
A week after inoculation, control animals showed symptoms of the disease and had high levels of virus in their blood. In contrast, the genetically modified pigs were perfectly healthy and showed no signs of infection. Several generations of genetically modified pigs have been followed and no adverse effects on health or fertility have been observed.
The same gene is involved in the replication of pestiviruses that infect cattle and sheep – less serious diseases, but which continue to circulate in the UK – and the team is currently investigating whether the same modification confers resistance to these species.
The breakthrough comes as many countries are relaxing rules around gene editing in agriculture, with the UK’s Precision Breeding Act paving the way for genetically modified crops. Countries like the United States, Japan and Brazil have already approved genetically modified livestock. Building on previous work at Roslin, Genus, a Basingstoke-based company, has generated pigs resistant to a virus that causes porcine reproductive and respiratory syndrome, which have been approved for sale in the United States and are expected to be released there in 2026.
Dr Simon Lillico, a researcher at the Roslin Institute and co-author, said: “In my mind there is a moral imperative that if we can create animals that are resistant to disease, we probably should. »
Dr Emily Clark, from EMBL’s European Bioinformatics Institute, who was not involved in the research, said: “Decades of genomic research have identified and precisely modified genes involved in disease resistance. Research like this helps create healthier animals, reduces losses for farmers in areas affected by swine fever and marks a major breakthrough in the use of genomics-based innovation to strengthen livestock resilience to disease. populations. »
The results are published in the journal Trends in Biotechnology.
