Press release

Oyster herpesvirus (OsHV-1 µvar) disease outbreak confirmed in Devon

Oyster herpesvirus (OsHV-1 µvar) has been confirmed in the River Teign in Devon

Pacific oysters

Following a report from a shellfish farmer on Monday 26 October of unusual mortalities in farmed Pacific (rock) oyster spat (Crassostrea gigas) at a farm site in the River Teign in Devon, a Fish Health Inspector from the Centre for Environment, Fisheries and Aquaculture Science (Cefas) visited the affected site in the Teign on Wednesday 28 October. Samples taken from the affected site were confirmed as positive for oyster herpesvirus (OsHV-1 µvar), and a new Containment Area Covering the tidal waters within the River Teign has been declared.

In accordance with Commission Regulation 175/2010, movements of shellfish out of the Containment Area covering the River Teign, have been restricted, following the confirmation of oyster herpes virus (OsHV-1 µvar).

Cefas acting on behalf of Defra has issued a Confirmed Designation prohibiting the movement of Pacific oysters from the containment area and applying the following additional control measures:

  • You must apply to the Fish Health Inspectorate for permission if you wish to move any Pacific oysters out of the Confirmed Designation area, including movements into purification centres (depuration plants).
  • You must notify the Fish Health Inspectorate of any increased or unexpected mortality observed in shellfish stocks.

OsHV-1 µvar affects Pacific oysters and can result in high rates of shellfish mortalities.

OsHV-1 µvar is an emerging disease that has been associated with high levels of mortality in Pacific oysters in France, Jersey and some bays in the Republic of Ireland.

In addition England and Wales continues to have OsHV-1µVar control areas in the Essex creeks (Colne, Mersea and Blackwater), along the north Kent coast and within Poole Harbour, Dorset.

There are no implications for human health.

Any suspicion of the presence of OsHV-1 in Pacific oysters should be immediately reported to:

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. CD22/2015, 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 24 November 2015