OYSTER HERPESVIRUS - NEW ZEALAND
********************************
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases <http://www.isid.org>
Date: Thu 2 Dec 2010
Source: World Fishing & Aquaculture [edited] <http://www.worldfishing.net/news101/nz-oysters-die-from-herpes-outbreak>
Puzzled scientists are battling to identify why millions of Pacific oysters are dying in New Zealand waters. Up to half of the juvenile Pacific oyster stocks in the North Island are thought to have died, and up to 10 percent of the adults, according to Oyster Industry Association chairman Callum McCallum.
Aquaculture New Zealand said up to 80 percent of juvenile oysters on some farms have died.
The European Food Safety Authority (EFSA) has called on animal health experts for a scientific opinion on widespread die-offs of Pacific oysters (_Crassostrea gigas_).
Acting on a request from the European Commission, EFSA has specifically asked whether the juvenile stocks may have been killed off by a combination of a herpes-like virus -- ostreid herpesvirus-1
(OsHV-1) -- and environmental factors.
In the UK, the movement of oysters from parts of the Kent coast has been banned after the herpes decimated juvenile Pacific oyster stocks.
The OsHV-1 virus has wiped out stocks in France in recent years and the UK has declared a containment area on the Thames and north Kent coasts.
A spokeswoman for the Centre for Environment, Fisheries and Aquaculture Science (CEFAS) said OsHV-1 is an emerging disease that has been associated with high levels of mortality in Pacific oysters in France, Jersey, and some bays in the Republic of Ireland.
In 2008 France's main marine research institute, French Research Institute for Exploitation of the Sea (Ifremer), set up a crisis team which found 40-100 percent of oysters aged 12 to 18 months were dying from the oyster herpes.
Scientists found that an increase or a sudden change in the water temperature was an important risk factor, but the introduction of non-certified possibly-infected spat, movements, and mixing of populations and age groups, among other husbandry practices, were key risk factors.
European authorities want increased biosecurity measures in their oyster aquaculture sector and tests on the health status of oyster spat before it is collected for farming.
McCallum said restrictions had been placed on the movement of oysters into the few North Island bays where farms were not affected or to the South Island.
Until this year [2010], around 3.5 million dozen Pacific oysters -- around 2800 tonnes -- were harvested annually in New Zealand's NZD 30 million (EUR 17.1 million/USD 22.6 million) industry, with the majority exported, mainly to Australia and Asia, but about half of the oysters due to be exported next year [2011] are now dead. Stocks for next year [2011] are going to be reduced considerably, McCallum said.
Aquatic disease specialists had taken approximately 250 samples for analysis, and Ministry of Agriculture and Forestry response manager Richard Norman said speculating on the cause of the deaths would be premature.
--
Communicated by:
Thomas James Allen
<tjallen@pipeline.com>
[Indeed it does seem to be an emerging disease, as even OIE is treating it as an emerging disease.
Clinical signs of the disease may include high levels of mortality particularly affecting juvenile stages of Pacific oysters. These signs usually appear when water temperatures exceed 16 deg C (60.8 deg F).
Currently there is no cure once this disease has infected an area.
However, there is a PCR test for early detection and potentially for confirmation.
Portions of this comment were extracted from <http://www.efishbusiness.co.uk/news/oyster-herpesvirus-outbreak.asp>.
- Mod.TG]
[The HealthMap/ProMED-mail interactive map of New Zealand can be seen at <http://healthmap.org/r/00*6>. - Sr.Tech.Ed.MJ]
[see also:
Oyster herpesvirus - Netherlands 20100910.3259 Oyster herpesvirus - England, Ireland: emerging, OIE 20100817.2858] ...................................tg/mj/dk
*##########################################################*
************************************************************
ProMED-mail makes every effort to verify the reports that are posted, but the accuracy and completeness of the
information, and of any statements or opinions based
thereon, are not guaranteed. The reader assumes all risks in
using information posted or archived by ProMED-mail. ISID
and its associated service providers shall not be held responsible for errors or omissions or held liable for any damages incurred as a result of use or reliance upon posted or archived material.STER HERPESVIRUS - NEW ZEALAND
********************************
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases <http://www.isid.org>
Date: Thu 2 Dec 2010
Source: World Fishing & Aquaculture [edited] <http://www.worldfishing.net/news101/nz-oysters-die-from-herpes-outbreak>
Puzzled scientists are battling to identify why millions of Pacific oysters are dying in New Zealand waters. Up to half of the juvenile Pacific oyster stocks in the North Island are thought to have died, and up to 10 percent of the adults, according to Oyster Industry Association chairman Callum McCallum.
Aquaculture New Zealand said up to 80 percent of juvenile oysters on some farms have died.
The European Food Safety Authority (EFSA) has called on animal health experts for a scientific opinion on widespread die-offs of Pacific oysters (_Crassostrea gigas_).
Acting on a request from the European Commission, EFSA has specifically asked whether the juvenile stocks may have been killed off by a combination of a herpes-like virus -- ostreid herpesvirus-1
(OsHV-1) -- and environmental factors.
In the UK, the movement of oysters from parts of the Kent coast has been banned after the herpes decimated juvenile Pacific oyster stocks.
The OsHV-1 virus has wiped out stocks in France in recent years and the UK has declared a containment area on the Thames and north Kent coasts.
A spokeswoman for the Centre for Environment, Fisheries and Aquaculture Science (CEFAS) said OsHV-1 is an emerging disease that has been associated with high levels of mortality in Pacific oysters in France, Jersey, and some bays in the Republic of Ireland.
In 2008 France's main marine research institute, French Research Institute for Exploitation of the Sea (Ifremer), set up a crisis team which found 40-100 percent of oysters aged 12 to 18 months were dying from the oyster herpes.
Scientists found that an increase or a sudden change in the water temperature was an important risk factor, but the introduction of non-certified possibly-infected spat, movements, and mixing of populations and age groups, among other husbandry practices, were key risk factors.
European authorities want increased biosecurity measures in their oyster aquaculture sector and tests on the health status of oyster spat before it is collected for farming.
McCallum said restrictions had been placed on the movement of oysters into the few North Island bays where farms were not affected or to the South Island.
Until this year [2010], around 3.5 million dozen Pacific oysters -- around 2800 tonnes -- were harvested annually in New Zealand's NZD 30 million (EUR 17.1 million/USD 22.6 million) industry, with the majority exported, mainly to Australia and Asia, but about half of the oysters due to be exported next year [2011] are now dead. Stocks for next year [2011] are going to be reduced considerably, McCallum said.
Aquatic disease specialists had taken approximately 250 samples for analysis, and Ministry of Agriculture and Forestry response manager Richard Norman said speculating on the cause of the deaths would be premature.
--
Communicated by:
Thomas James Allen
<tjallen@pipeline.com>
[Indeed it does seem to be an emerging disease, as even OIE is treating it as an emerging disease.
Clinical signs of the disease may include high levels of mortality particularly affecting juvenile stages of Pacific oysters. These signs usually appear when water temperatures exceed 16 deg C (60.8 deg F).
Currently there is no cure once this disease has infected an area.
However, there is a PCR test for early detection and potentially for confirmation.
Portions of this comment were extracted from <http://www.efishbusiness.co.uk/news/oyster-herpesvirus-outbreak.asp>.
- Mod.TG]
[The HealthMap/ProMED-mail interactive map of New Zealand can be seen at <http://healthmap.org/r/00*6>. - Sr.Tech.Ed.MJ]
[see also:
Oyster herpesvirus - Netherlands 20100910.3259 Oyster herpesvirus - England, Ireland: emerging, OIE 20100817.2858] ...................................tg/mj/dk/ll
*##########################################################*
************************************************************
ProMED-mail makes every effort to verify the reports that are posted, but the accuracy and completeness of the
information, and of any statements or opinions based
thereon, are not guaranteed. The reader assumes all risks in
using information posted or archived by ProMED-mail. ISID
and its associated service providers shall not be held responsible for errors or omissions or held liable for any damages incurred as a result of use or reliance upon posted or archived material.
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