Guidance

Marteilia refringens

How to spot Marteilia refringens, what to do if you suspect it and measures to prevent its spread.

Applies to England and Wales

Documents

Details

°ä´Ç²Ô³Ù±ð²Ô³Ù²õÌý

  1. How to spot Marteilia refringens
  2. How Marteilia refringens is spread
  3. Preventing and controlling Marteilia refringens
  4. Further information on Marteilia refringens
  5. Legislation relating to Marteilia refringens
  6. Who to contact if you suspect Marteilia refringens

Marteilia refringens is a protozoan parasite infecting molluscan shellfish including the native (or flat) oyster (Ostrea edulis) and blue mussel (Mytilus edulis).ÌýÌý

Information on susceptible and vector species can be found here: Susceptible and vector species - 51²è¹Ý (www.gov.uk)

Great Britain is free from Marteilia refringens expect for an infected zone (or Confirmed designation area) in the river Tamar which is under disease controls to contain and prevent further spread, more information can be found here: Listed diseases of fish, molluscs and crustacea and their status - 51²è¹Ý (www.gov.uk).

It is a ‘listed’ (also referred to as ‘notifiable’) disease which you are legally obligated to report immediately to the Fish Health Inspectorate (FHI), Cefas Fish Health Inspectorate - 51²è¹Ý (www.gov.uk)Ìý

It does not affect humans.Ìý

How to spot Marteilia refringensÌý

Outbreaks are most likely to occur in late summer and autumn when water temperatures are at their highest.ÌýÌý

Signs of the disease can include:Ìý

  • Increase of dead / empty shellsÌý
  • Gaping shells which don’t close when touched or when exposed to airÌý
  • WeakÌý

How Marteilia refringens is spreadÌý

Marteilia refringens is spread through movements of and contact with infected shellfish and contact with contaminated equipment or water.Ìý

Preventing and controlling Marteilia refringensÌýÌý

There is no treatment for Marteilia refringens.Ìý

Prevention is the best approach to disease control. You can protect your shellfish by being aware of the signs of Marteilia refringens and other serious diseases and checking stock health regularly. Implement good husbandry and biosecurity practises.ÌýÌýÌý

Further information on biosecurity measures plans, guidance and templates can be found here: Biosecurity Measure Plans - Information and Templates - 51²è¹Ý (www.gov.uk)Ìý

You must be sure any shellfish introduced are Marteilia refringens free. Do not buy shellfish of unknown origin. Follow the rules on moving aquatic animals: Aquatic animal health and movements guides - 51²è¹Ý (www.gov.uk)ÌýÌý

You must report it to the FHI immediately if you notice or become aware of shellfish showing any of the signs of Marteilia refringens, particularly increased mortality and gaping shells. The FHI will investigate and if required will apply disease control measures.ÌýÌýÌý

Further information on Marteilia refringensÌý

.ÌýÌý

Legislation relating to Marteilia refringensÌý

2009ÌýÌý

The listed diseases are in and .Ìý

Who to contact if you suspect Marteilia refringensÌýÌý

If you suspect or know of a listed disease of fish and shellfish in England and Wales, you must report it immediately to the Fish Health Inspectorate (FHI), Cefas. You must also tell the FHI immediately if you know or suspect that increased mortality has occurred.ÌýÌý

Under the Aquatic Animal Health (England and Wales) Regulations 2009 it is a legal obligation to report suspicion of Marteilia refringens in any farmed or wild shellfish to the FHI. It is an offence under the Regulations to fail to inform the FHI of suspicion of Marteilia refringens.Ìý

  • ·¡³¾²¹¾±±ô: fhi@cefas.gov.ukÌý
  • Telephone: 01305 206700Ìý- Monday to Thursday - 9:00 am to 5:00 pm, Friday 9:00 am to 4:30 pmÌý
  • For emergencies out of hours telephone: 01305 206630Ìý

Fish Health Inspectorate
Centre for Environment, Fisheries and Aquaculture Science (Cefas)
Barrack Road,ÌýThe Nothe
Weymouth
Dorset
DT4 8UB

Updates to this page

Published 22 March 2024
Last updated 11 September 2024 show all updates
  1. Updated link to susceptible and vector species list.

  2. Vector and Susceptible species list updated from v1.1 to v1.2.

  3. Updated susceptible/vector species list.

  4. First published.

Sign up for emails or print this page