Press release

Oyster herpesvirus-1 microvariant disease outbreak confirmed in Essex

Oyster herpesvirus-1 microvariant (OsHV-1 µvar) has been confirmed in a shellfish fishery in the River Roach, Essex

An outbreak of Oyster herpesvirus-1 microvariant (OsHV-1 µvar) has been confirmed in Pacific oysters (Crassostrea gigas) in the River Roach, Essex.

There are no implications for human health: the virus only affects Pacific oysters.

OsHV-1 µvar is a virulent viral disease affecting the Pacific oyster, also known as the rock or cupped oyster. This is the only species of shellfish that is currently known to be susceptible to this virus.

The virus is notifiable under the Aquatic Animal Health (England & Wales) Regulations 2009. Where notifiable diseases are suspected or confirmed disease control measures are applied in the form of a designation notice to movements of live and dead aquatic animals, (including their eggs and/or gametes) and to certain site activities. The purpose of the movement controls is to restrict the spread of the disease to other parts of the coast.

Existing statutory controls for OsHV-1 µVar in the surrounding areas have been reviewed and the pre-existing control areas for the River Crouch, River Colne and River Blackwater have been merged and expanded to incorporate the River Roach.

Confirmed Designation Notices CD04/2012 and CD16/2014 have been withdrawn and replaced by one new designation notice CD06/2015, which now controls the movements of live Pacific oysters into and out of the area. You must apply to the Fish Health Inspectorate if you want to move any live Pacific oysters into or out of the designated area.

In addition England and Wales continues to have OsHV-1µVar control areas in Whitstable, Kent and Poole Harbour, Dorset.

Anyone who imports, farms, depurates and fishes for Pacific oysters (Crassostrea gigas) should take precautions to prevent the spread of OsHV-1 µvar. You must notify the FHI immediately if you know of or suspect the presence of Oyster herpesvirus-1 microvariant (OsHV-1 µvar), and to report increased or unusual mortalities in Pacific oysters (Crassostrea gigas)

Fish Health Inspectorate

Additional notes

  1. Cefas is an executive agency of the Department for Environment, Food and Rural Affairs (Defra). The Fish Health Inspectorate (FHI), based at Cefas’ Weymouth laboratory, is dedicated to maintaining and improving fish and shellfish health in England and Wales. Its primary role is to act for Defra and Welsh Government (WG) in undertaking statutory and inspection duties resulting from the EU fish health regime and other national legislation in the area of fish and shellfish health. The FHI is responsible for health certification of fish and shellfish movements from other countries, and runs an enforcement programme aimed at preventing the illegal importation of these animals.
  2. Oyster herpesvirus-1 microvariant (OsHV-1 µvar). is a notifiable disease under The Aquatic Animal Health (England and Wales) Regulations 2009. Outbreaks of this disease have been subject to statutory control in GB since 2010.
  3. CD06/2015, issued under the Aquatic Animal Health, England and Wales Regulations 2009 restricts the movement of live shellfish, into and out of the designated area without the prior written consent of the Fish Health Inspectorate at Cefas and applies additional specific biosecurity measures.
Published 22 July 2015