Date: Wednesday 24 August 2011

In August 2011 Fish Health Inspectors from the Centre for Environment, Fisheries and Aquaculture Science (Cefas) examined a sample of blue (edible) mussels from the Tamar estuary, Cornwall. This followed reports of the presence of Marteilia species from an earlier study on the use of mussels as indicator organisms of environmental change. Diagnostic tests confirmed Marteilia refringens in four individuals from a sample of 150 mussels. However there was no evidence of morbidity or mortality in the mussels.

This is the first record of Marteilia refringens in the UK. The disease is listed in legislation as non-exotic to the European Union and has been previously found in native oysters and in mussels in the coastal waters of a number of member states including France, Spain, Portugal and Greece.

Cefas acting on behalf of Defra has issued a confirmed designation and you must apply to the Fish Health Inspectorate for permission if you wish to move any oysters or mussels out of or into the area, including movements into purification centres (depuration plants).  Additionally:

• You must continue to notify the Fish Health Inspectorate of any increased or unexpected mortality observed in shellfish stocks.
• Confirmed Designation number CD Area 01 issued on 27 March 2009 for the control of Bonamia ostreae in Ostrea edulis (native oysters) remains unaffected by this notice.

Further information about M.refringens is available at: http://www.defra.gov.uk/aahm/files/Guide-Marteiliosis.pdf

There are no implications for human health.

Any suspicion of the presence of M.refringens should be immediately reported to:

The Fish Health Inspectorate,
Centre for Environment, Fisheries and Aquaculture Science (Cefas).

Tel: 01305 206700

E-mail: fhi@cefas.co.uk

Notes to editors:

• CD06/2011, issued under the Aquatic Animal Health (England and Wales) Regulations 2009 restricts the movement of any oysters or mussels from within the designated area without the prior written consent of the Fish Health Inspectorate at Cefas.
• Marteilia refringens is an important pathogen of native oysters and infection can result in mass mortalities. Extensive surveillance of shellfish from around the UK has never detected M.refringens in native oyster stocks. Infection in mussels is not always associated with mortality.
• Further information is available at www.defra.gov.uk/aahm, or from Cefas, Fish Health Inspectorate, The Nothe, Barrack Road, Weymouth, Dorset, DT4 8UB. Tel: 01305 206700 or e-mail: fhi@cefas.co.uk

Press contact:

Anne McClarnon: 01502 524370 / anne.mcclarnon@cefas.co.uk