Oyster herpesvirus disease has been found in the River Exe and River Teign in Devon, southwest England.

The government says the virus, also known as OsHV-1, was found after a shellfish farmer reported "unusual mortalities" of Pacific oysters at a farm site in the River Exe in Devon.

The disease, which poses no threat to humans, previously killed eight million shellfish in Whitstable, Kent, in 2010. It was also detected in an Essex river in 2015.

This was after the variant wiped out between seven and eight billion oysters during its initial outbreak in France in 2008.

The government says it is prohibiting the movements of shellfish out of both rivers - including the surrounding coastline.

It has also ordered any fishermen who notice any unexpected deaths among oysters to immediately notify the Fish Health Inspectorate.

Read more on Sky News:
World's tallest dog dies aged 3
Couple save baby shark during scuba diving trip

These precautions are already in place in areas of Essex, Kent and Suffolk; Butley Creek; and Poole Harbour - where the disease has been detected in the past.

Experts say herpes still wipes out 50 to 70 per cent of oysters annually in France, though a vaccine was developed in 2021 which scientists believed would offer complete protection.

Creators of the vaccine are still waiting to receive the green light from French authorities, and the UK government has not alluded to any precautionary measure other than restricting the movement of shellfish in contaminated regions.