Oyster herpes outbreak confirmed in River Roach in Essex Published duration 22 July 2015

image copyright AP image caption Restrictions have been placed on the movement of live oysters because of the herpes outbreak

An outbreak of herpes which can decimate stocks of young shellfish has been found in an Essex river.

The Centre for Environment, Fisheries and Aquaculture Science (Cefas) said the virus had been discovered in molluscs in the River Roach.

As a result, movement of live Pacific oysters has been restricted in the area, home to a number of oyster farms.

An outbreak of the virus in Whitstable, Kent in 2010 is estimated to have killed more than eight million oysters

Cefas said existing controls in surrounding areas, including the River Crouch, River Colne and River Blackwater, had been merged and expanded to include the River Roach.

"There are no implications for human health: the virus only affects Pacific oysters," the centre said in a statement.

Oyster herpes occurs when water temperatures exceed 16C (61F). There is no cure and wipes out 60-100% of juvenile shellfish, experts say