Authorities have described the case, the first in Wales since 2013, as an isolated incident that hasn’t affected food chain

A case of BSE – so-called “mad cow disease” – has been found in an animal on a farm in Wales.

The case is the first in Wales since 2013 but the devolved government in Cardiff described it as isolated and said the animal had not entered the human food chain. There have been six cases in the UK since 2013.

However, the discovery will be a blow to the beef industry in Wales and farming in general. Opposition politicians called on the Welsh government to make sure farmers were supported and to provide more information about the case.

Rebecca Evans, Welsh government deputy minister for farming and food, said it was discovered as a result of strict control measures, which see all animals over four years old that die on a farm routinely tested for the disease.

Government scientists will now work on finding out what caused the infection in the animal, and other cows it came into contact with – plus any offspring – will be traced and destroyed.

In a statement, Evans said: “The Welsh government and the animal and plant health agency (APHA) have confirmed a case of classical BSE in a single deceased bovine on a farm in Wales.

“It did not enter the human food chain and the Food Standards Agency and Public Health Wales have confirmed there is no risk to human health as a result of this isolated case.

“My officials are working closely with Defra [the UK’s Department for Environment, Food and Rural Affairs] and the APHA to investigate the circumstances of this case.

“In addition to the measures we have in place for fallen stock and animal feed, there is a strict control regime to protect consumers. This includes the removal of ‘specified risk material’, such as the spinal column, brain and skull from carcasses. Identification of this case demonstrates that the controls we have in place are working well.

“Beef across the UK continues to be produced in compliance with the World Organisation for Animal Health rules.”

The discovery of BSE – bovine spongiform encephalopathy – in the UK became a national crisis in the late 1980s. Millions of animals were destroyed to bring the disease under control and nearly 200 people have died of the linked human disease, vCJD.

Prof Hugh Pennington, emeritus professor of bacteriology at the University of Aberdeen, said on Thursday that scientists would be working hard to understand the cause of the disease in the animal. “One crucial factor is its age. Is it an old cow that was infected years ago, for example?”

But he did not believe the finding was a huge cause for concern. The government has not said how old the cow was or the precise location of the case.

William Powell, Welsh Liberal Democrat shadow farming minister and assembly member for Mid and West Wales, said: “This is, of course, very disappointing news. However, I can’t emphasise enough that we have immensely robust control measures in place to detect and prevent any infected produce from entering the food chain. Both the Food Standards Agency and Public Health Wales have confirmed there is no risk to human health.

“The drop in prices has already badly hit farmers financially and it is important they know they have our full support. Wales has the best beef produce in the world and that is something our nation can continue to be immensely proud of. It is vitally important that the Welsh government keep members of the public regularly updated on this issue.”