On October 22, 2025, scientists at the University of Edinburgh’s Roslin Institute announced a breakthrough that could reshape the future of livestock farming: they have successfully gene-edited pigs to be resistant to classical swine fever (CSF), a highly contagious and often fatal viral disease that has plagued pig populations worldwide. The achievement, detailed in Trends in Biotechnology, not only promises to protect herds from devastating outbreaks but also hints at a broader revolution in animal health and sustainable agriculture.
Classical swine fever, sometimes called hog cholera, is infamous among farmers and veterinarians alike. The virus can cause high fevers, diarrhoea, miscarriages, and, in severe cases, death. According to New Scientist, the disease has been responsible for massive losses: in 1997, the Netherlands culled six million pigs to contain an outbreak, and Japan has struggled with recurring cases since 2018. While the UK and US are currently free of CSF, the virus remains endemic in parts of Asia, Africa, Latin America, and Europe, leading to trade bans and significant financial hardship for farmers, as reported by BBC and The Scotsman.
Vaccines do exist for CSF, but, as Christine Tait-Burkard of the University of Edinburgh explained to New Scientist, “Vaccination takes a lot of coordination and monitoring.” Countries that vaccinate their pigs often face export restrictions to disease-free regions, and lapses in vaccination can quickly lead to outbreaks, as seen recently in the Philippines. The logistical and economic burdens are considerable, making a more permanent solution highly desirable.
Enter gene editing. The Roslin Institute team, led by Dr. Simon Lillico, used CRISPR technology to make a precise change in a gene called DNAJC14. This gene encodes a protein that the CSF virus relies on to reproduce inside pig cells. By altering just a single amino acid in this protein, the scientists effectively blocked the virus’s ability to replicate. “Our research highlights the growing potential of gene editing in livestock to improve animal health and support sustainable agriculture,” Dr. Lillico told The Scotsman. “While previous research had identified this protein’s role in cell cultures, translating that into living animals is a major step, and one that requires the infrastructure to breed, monitor, and safely test gene-edited livestock.”
The process was meticulous. Researchers first demonstrated in laboratory cell cultures that modifying DNAJC14 could prevent the virus from reproducing. Then, they made the same genetic change in pig embryos, which were implanted into surrogate mothers. Once the pigs reached adulthood, they were exposed to the CSF virus in a secure, biosecure facility operated by the Animal & Plant Health Agency (APHA). The results were striking: gene-edited pigs showed no signs of infection, while unedited pigs displayed the typical symptoms of the disease. “These animals were completely resistant to replication of the virus and remained happy and healthy throughout the study,” said Helen Crooke, Mammalian Virology Deputy Leader at APHA, as quoted by New Scientist.
Importantly, the gene-edited pigs exhibited no observable negative effects on their health or development. “The genetic change offered complete protection from infection without any observable negative effects on the animals’ health or development,” noted the research team in BBC coverage. This point is crucial, as animal welfare is a key consideration in the regulatory approval of gene-edited livestock. Dr. Lillico emphasized, “The team hasn’t seen any adverse effects in the pigs that are resistant to classical swine fever, but further studies will be needed to confirm this.”
The implications of this work extend far beyond just pigs. The pestivirus family, to which CSF belongs, also includes viruses that affect cattle and sheep, such as bovine viral diarrhea virus and border disease virus. According to BBC, the same gene edit could theoretically be applied to these other livestock species, potentially offering a broader shield against related diseases. The Edinburgh team is already investigating whether this approach will work in cattle and sheep.
Commercial interest in the technology is strong. The project was conducted in collaboration with Genus, a major international animal genetics company that has already developed gene-edited pigs resistant to porcine reproductive and respiratory syndrome (PRRS), another major swine disease. Genus’s PRRS-resistant pigs have been approved in the US, Brazil, and other countries, and the company is awaiting regulatory decisions in Mexico, Canada, and Japan. The hope is that similar regulatory pathways can be opened for CSF-resistant pigs, further accelerating the adoption of gene editing in agriculture.
Gene editing differs from traditional genetic engineering in that it often involves making changes that could occur naturally. As a result, many countries are regulating gene editing less strictly, at least for plants, and some have started to approve gene-edited animals as well. “Where gene editing is used to make tiny changes that could occur naturally, many countries are regulating it less strictly than conventional genetic engineering,” New Scientist reported. Still, in England, the rules for gene-edited livestock are not yet finalized, though requirements are expected to ensure that edits do not negatively affect animal welfare.
Beyond disease resistance, the potential upsides are significant. Widespread use of gene-edited pigs could improve animal welfare, boost productivity, reduce greenhouse gas emissions, and even lower prices for consumers. “It would help towards sustainable livestock production, and with nice healthy, happy pigs,” said Helen Crooke of APHA. As BBC explained, gene editing could become part of an integrated disease prevention strategy, working alongside vaccines and biosecurity measures to minimize the risk of outbreaks and safeguard food supplies.
Of course, there are still hurdles ahead. Regulatory approval processes must be navigated, and public acceptance of gene-edited animals remains a topic of debate. Some argue that gene editing, when used responsibly, is a natural extension of traditional breeding, while others urge caution and rigorous oversight. As Dr. Lillico observed, “There are certainly traditionally bred animals that have lower welfare associated with them. A level playing field would be lovely.”
The research was supported by the UK Biotechnology & Biological Sciences Research Council and conducted in collaboration with the Animal & Plant Health Agency, the University of Lubeck in Germany, and Genus. The Large Animal Research and Imaging Facility at the University of Edinburgh played a key role in enabling the breeding and testing of gene-edited livestock.
While the world waits to see how quickly these gene-edited pigs might make their way to farms, the sense of possibility is palpable. The Roslin Institute’s achievement marks a significant stride toward a future where deadly livestock diseases like classical swine fever might be consigned to history books, and where gene editing helps build a more resilient, sustainable, and humane agricultural system.
