Ian Laing

Some oyster diseases

List of Diseases

Bower, S.M. and McGladdery, S.E. (2003): Synopsis of Infectious Diseases and Parasites of Commercially Exploited Shellfish

URL: http://www-sci.pac.dfo-mpo.gc.ca/shelldis/title_e.htm

The Single European Union Market• Animal health conditions for placing aquaculture animals

on the market ~ EC Directive 91/67, as amended.

Europa Animal Health and Welfare Web site

Listed diseases - THEN

95/70Haplosploridium nelsoni

Haplosploridium costale

Perkinsus marinus

Perkinsus olseni

Mikrocytos mackini

Mikrocytos roughleyi

Oyster velar virusMarteilia sydneyi

91/67Bonamia ostreae

Marteilia refringens

2003/390NON-Susceptible speciesBonamia – Pacific oysters, mussels and clamsMarteilia – Pacific oysters

OIE - International Organisationfor Animal Health

Aquatic Animal Code and Manual

2006/88

Susceptible species

DiseasesFlat oysters

Cupped oysters

Mussels

Bonamia ostreae YesMarteilia refringens

Yes Yes

Perkinsus marinus

Yes

Bonamia exitiosa YesMicrocytos mackini

Yes Yes

Listed diseases - NOW

Aims of the legislation• Prevent the spread of serious disease• Allow trade

This means• Controlling the movement of shellfish• Import and export checks

Bonamiasis• Introduced into Europe in 1979 - Brittany

Bonamia ostreae is an intracellular plasmodial protozoan parasite (2-5m) that belongs to the Haplosporidium group. It affects the granular blood cells (haemocytes) of flat oysters.

Bonamia ostreae

Shellfish News

Project BOLCI

Web site – www.bonamia.com

Google – 14,000 resultsASFA – 168 papers

•EU Health Rules (91/67/EEC)•UK programmes approved (92/528/EEC)•Approved Zones (2002/300/EC)

Zones in Great Britain

1993 – 20053 infected areas

2006 - Loch Sunart (E) and Milford Haven (F) 2007 – West Loch Tarbert (G)2008 – North Kent

Meanwhile, in Ireland

1993 - 2002

2003 – Achill Sound and Blacksod Bay

2005 – Lough Foyle2006 – Lough Swilly2008 - Strangford Lough

“Placing on the market” (2006/88 continued)

• Authorisation of Aquaculture Production Businesses

• includes dispatch and purification centres

• Susceptible and vector species• Risk-based surveillance

• for increased mortality

Surveillance for mortalityFishFish MolluscsMolluscs

Mobile SedentaryVisible behaviour StaticEndoskeleton ShellContained Open (sea bed)

Marteilia refringens

Marteilia (type M)in mussels inSouthampton Water(and elsewhere)

One species?Two types?

Pacific oysters

• Oyster Herpes Virus• Vibrio splendidus• Environmental factors

“Summer mortality”

500 μm

2006/88 Susceptible species

Diseases

White Spot Disease

All decapod crustaceans

Taura Syndrome Three tropical shrimp spp

Yellowhead disease

Seven tropical shrimp spp

Listed diseases - NEW

White spot disease (WSD)

• Global spread via live and frozen animal movements – 100% mortality in days – no effective treatment

• Can be transmitted to European decapods (crayfish, crabs, lobsters)

• Experimental infection of European lobster via feeding of WSD-infected prawns

• Causes disease within the European water temperature range

• Little research into vectors/carrier hosts

IS THERE A THREAT IN EUROPE?

• Small crustacean aquaculture industry

• Large and very valuable marine fishery for prawns, lobsters and crabs

• Potential routes of entry of WSD to Europe – larvae or broodstock for aquaculture, imported fresh and frozen prawns or live potentially carrier species for consumption

• Significant movement of fresh, frozen and live European crustaceans within the EU

White spot disease (WSD)

I hope that was not too complicated

Note: None of these diseases affect humans