The first case of bird flu in sheep has been found in the UK, the nation’s chief veterinary officer has confirmed.

The exact location of the farm has not been revealed, but a government spokesperson said the case was identified on a site in Yorkshire where bird flu had been confirmed in captive birds.

The spokesperson said the single infected sheep had been “humanely culled” and no further cases among the flock were found after “extensive testing”.

“There is no evidence to suggest an increased risk to the nation’s livestock population,” they added.

Christine Middlemiss, the UK’s chief veterinary officer, said “strict” measures had been put in place to prevent the further spread of the disease.

She added: “While the risk to livestock remains low, I urge all animal owners to ensure scrupulous cleanliness is in place and to report any signs of infection to the Animal Plant Health Agency immediately.”

Bird flu, also known as avian influenza or H5N1, is a disease caused by a virus that infects birds and sometimes other animals.

Dr Meera Chand, emerging infection lead at the UK Health Security Agency, said current evidence “suggests that the avian influenza viruses we’re seeing circulating around the world do not spread easily to people”.

Dr Chand added: “The risk of avian flu to the general public remains very low.”

The Department for Environment, Food and Rural Affairs (Defra) said 1.78 million farmed and captive birds had been culled between November and February due to the spread of the disease across the UK.

A government spokesperson said the infected sheep was a female who had been showing signs of mastitis, an inflammation of the breast tissue.

The lambs of the affected ewe tested negative for bird flu, the spokesperson added.

While this is the first time this virus has been reported in a sheep, bird flu has previously been detected in livestock in other countries, according to Defra.

The National Sheep Association, which represents the views and interests of sheep producers in the UK, said mixing different animals was “questionable at the best of times, but should be avoided when England is undergoing a period of mandatory housing measures for poultry due to bird flu outbreaks”.

Defra has placed England in an “avian influenza protection zone” to prevent bird flu and stop it spreading.

Thirteen regions have also seen mandatory housing measures introduced, which state that birds must be kept inside.

They are Cheshire, Hull, East Riding of Yorkshire, Herefordshire, Lancashire, Merseyside, Norfolk, North Yorkshire, Shropshire, Suffolk, Worcestershire, and York.

The Food Standards Agency said properly cooked poultry and poultry products, including eggs, remained safe to eat.