Ian Laing Some oyster diseases List of Diseases

Ian Laing

Some oyster diseases

List of Diseases Bower, S. M. and Mc. Gladdery, 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 91/67 95/70 Bonamia ostreae Haplosploridium nelsoni Marteilia refringens Haplosploridium costale Perkinsus marinus 2003/390 NON-Susceptible species Bonamia – Pacific oysters, mussels and clams Marteilia – Pacific oysters Perkinsus olseni Mikrocytos mackini Mikrocytos roughleyi Oyster velar virus Marteilia sydneyi

OIE - International Organisation for Animal Health Aquatic Animal Code and Manual

Listed diseases - NOW 2006/88 Susceptible species Diseases Flat oysters Bonamia ostreae Yes Marteilia refringens Yes Perkinsus marinus Cupped oysters Yes Bonamia exitiosa Yes Microcytos mackini Yes Mussels Yes

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 -5 m) that belongs to the Haplosporidium group. It affects the granular blood cells (haemocytes) of flat oysters.

Bonamia ostreae Web site – www. bonamia. com Google – 14, 000 results ASFA – 168 papers Project BOLCI Shellfish News

Zones in Great Britain 1993 – 2005 3 infected areas 2006 - Loch Sunart (E) and Milford Haven (F) 2007 – West Loch Tarbert (G) 2008 – North Kent • EU Health Rules (91/67/EEC) • UK programmes approved (92/528/EEC) • Approved Zones (2002/300/EC)

Meanwhile, in Ireland 1993 - 2002 2003 – Achill Sound and Blacksod Bay 2005 – Lough Foyle 2006 – Lough Swilly 2008 - 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 mortality Fish Molluscs Mobile Visible behaviour Endoskeleton Contained Sedentary Static Shell Open (sea bed)

Marteilia refringens One species? Two types? Marteilia (type M) in mussels in Southampton Water (and elsewhere)

Pacific oysters “Summer mortality” • Oyster Herpes Virus • Vibrio splendidus • Environmental factors 500 μm

Listed diseases - NEW 2006/88 Diseases Susceptible species White Spot Disease All decapod crustaceans Taura Syndrome Three tropical shrimp spp Yellowhead disease Seven tropical shrimp spp

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

White spot disease (WSD) 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

I hope that was not too complicated Note: None of these diseases affect humans