Mikrocytos mackini
How to spot Mikrocytos mackini, what to do if you suspect it and measures to prevent its spread.
Applies to England and Wales
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Contents
- How to spot Mikrocytos mackini
- How Mikrocytos mackini is spread
- Preventing and controlling Mikrocytos mackini
- Legislation relating to Mikrocytos mackini
- Who to contact if you suspect Mikrocytos mackini
Mikrocytos mackini is a protozoan parasite which affects oyster species including Pacific oysters (Magallana [Syn. Crassostrea] gigas) and native oysters (Ostrea edulis).
Information on susceptible and vector species can be found here: GB Lists of susceptible and vector species.
Great Britain is free from Mikrocytos mackini, and 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 - GOV.UK (www.gov.uk)
There has never been a recorded outbreak of Mikrocytos mackini in the UK.
It does not affect humans.
How to spot Mikrocytos mackini
Outbreaks are likely to occur during the spring when water temperature are less than 10°C.
Signs of the disease can include:
- Increase of dead / empty shells
- Gaping shells which don’t close when touched or when exposed to air
- Small abscesses, usually green in colour on soft tissue, with brown scars on shells
How Mikrocytos mackini is spread
Mikrocytos mackini is spread through movements of and contact with infected shellfish and contact with contaminated equipment or water.
Preventing and controlling Mikrocytos mackini
There is no treatment for Mikrocytos mackini.
Prevention is the best approach to disease control. You can protect your shellfish by being aware of the signs of Mikrocytos mackini and other serious diseases and checking stock health regularly. Implement good husbandry and biosecurity practises.
Further information on biosecurity measures plans, guidance and templates can be found here: Biosecurity Measure Plans - Information and Templates - GOV.UK (www.gov.uk)
You must be sure any shellfish introduced are Mikrocytos mackini free. Do not buy shellfish of unknown origin. Follow the rules on moving aquatic animals: Aquatic animal health and movements guides - GOV.UK (www.gov.uk)
You must report it to the FHI immediately if you notice or become aware of shellfish showing any of the signs of Mikrocytos mackini, particularly increased mortality and gaping shells. The FHI will investigate and if required apply disease control measures.
Legislation relating to Mikrocytos mackini
The Aquatic Animal Health (England and Wales) Regulations 2009
The listed diseases are in Regulation 1251/2008 as amended by the Animals, Aquatic Animal Health, Invasive Alien Species, Plant Propagating Material and Seeds (Amendment) (EU Exit) Regulations 2020, at Chapter 2, Annex 1A and Schedule 1 of The Aquatic Animal Health (England and Wales) Regulations 2009.
Who to contact if you suspect Mikrocytos mackini
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.
Under the Aquatic Animal Health (England and Wales) Regulations 2009 it is a legal obligation to report suspicion of Mikrocytos mackini 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 Mikrocytos mackini.
- Email: fhi@cefas.gov.uk
- Telephone: 01305 206700 - Monday to Thursday - 9:00 am to 5:00 pm, Friday 9:00 am to 4:30 pm
- For emergencies out of hours telephone: 01305 206630
Fish Health Inspectorate
Centre for Environment, Fisheries and Aquaculture Science (Cefas)
Barrack Road, The Nothe
Weymouth
Dorset
DT4 8UB