LONDON (Reuters) - A British animal genetics firm, working with U.S. scientists, has bred the world’s first pigs resistant to a common viral disease, using the hot new technology of gene editing.

Genus, which supplies pig and bull semen to farmers worldwide, said on Tuesday it had worked with the University of Missouri to develop pigs resistant to Porcine Reproductive and Respiratory Syndrome Virus (PRRSv).

The condition, also known as blue-ear disease, can be fatal as it affects the animals’ immune system and costs farmers hundreds of millions of dollars a year. There is no cure.

By using precise gene editing, the team from the University of Missouri was able to breed pigs that do not produce a specific protein necessary for the virus to spread in the animals. Their research was published in journal Nature Biotechnology.

Early-stage studies showed the new PRRSv resistant pigs, when exposed to the virus, did not get sick and continued to gain weight normally.

The development of these resistant pigs is further proof of the power of gene editing, which is taking the biotech industry by storm. Genus Chief Scientific Officer Jonathan Lightner said it was “a potential game-changer for the pork industry”.

Editing the genes of living organisms holds out great promise for treating diseases and improving agricultural crops and animal species. But when applied to humans it could also be used to create “designer babies”, prompting critics to call for a global ban on genetic modification of human embryos.

The technology allows scientists to edit genes by using biological “scissors” that operate a bit like a word-processing program that can find and replace selected stretches of DNA.

It has been put to work in laboratories around the world, even as the ethical and safety issues it raises are fiercely debated.

An international summit on human gene editing in Washington last week urged caution on human gene editing but said editing genes in human embryos was permissible for research purposes.

The work on Genus’s gene-edited pigs is still at an early stage and Lightner said there were several critical challenges ahead to fully develop and commercialize the technology.

Liberum analyst Sophie Jourdier said commercialization would likely take five years or more but the new resistant pig line would add to Genus’s long-term growth prospects, given the economic importance of PRRSv.

PRRSv affects millions of pigs and costs the swine industry around $700 million a year in the United States and 1.5 billion euros ($1.6 billion) in Europe, according to a 2011 Iowa State University study cited by Genus.