VIRAL HAEMORRHAGIC SEPTICAEMIA UPDATE –

The National Control Centre at the Cefas Weymouth Laboratory has
confirmed that viral haemorrhagic septicaemia (VHS) virus had been
detected in a sample of grayling

The National Control Centre at the Cefas Weymouth Laboratory has confirmed that viral haemorrhagic septicaemia
(VHS) virus had been detected in a sample of grayling taken from the River Nidd below the outlet of the farm
infected with the disease. The infected fish showed no clinical signs of the disease.

The discovery was made through comprehensive sampling. Cefas is continuing to test wild fish in the river,
both below and above the infected farm to determine the extent of infection.

Although there is no scientific evidence that VHS infection causes significant disease outbreaks in wild
freshwater fish stocks, any persisting infection in wild stocks could be a source of infection or
re-infection for trout farms in the vicinity through VHS virus contamination of the river supply to the farms.

There have been no further cases of the disease on trout farms in the Ouse/Don catchments of North Yorkshire
affected by the current case. The first round of testing on all farmed sites has returned negative results
so far and is due to be completed later this week. A second round of testing began last week with results
expected by the middle of July. Results of the further testing will be made known when they have been completed.
Fish farmers in the affected area and other stakeholders are being kept informed of the situation.

VHS has no implications for human health.

NOTES FOR EDITORS

The sample was confirmed positive by the CEFAS National Control Centre on 19th June.

On the 22nd May, Fish Health Inspectors from the Centre for Environment Fisheries and Aquaculture Science
(Cefas), acting on behalf of Defra, inspected a trout farm in Yorkshire following a report from the farm
manager of high levels of mortality in the farm stock. Samples were taken and analysed at the Cefas Weymouth
laboratory, and the presence of Viral Haemorrhagic Septicaemia (VHS) has been confirmed. VHS is a notifiable
disease which affects mainly farmed rainbow trout, and can cause significant mortality.

This is the first outbreak of VHS recorded in mainland Great Britain, although there was an outbreak of the
marine form of the disease in farmed turbot in the Isle of Gigha in 1994.

The Diseases of Fish (Designated Areas) (England)(No.2) Order 2006 restricts the movement of any live
fish or live eggs of fish into or out of the designated area and farms without the prior written consent of Defra.

The designated area is now defined as:

• the geographical area from which water drains to form the Yorkshire River Ouse catchment to its
Estuarial Water Limit at Boothe Ferry Bridge, National Grid Reference SE7333 2625; and

• the geographical area from which water drains to form the River Don catchment to its Estuarial
Water Limit at Goole, National Grid Reference SE7495 2288.

Further information on VHS and other serious freshwater diseases can be found on the Defra website
and in its “Combating Fish Disease” publication. Our sister site, www.efishbusiness.co.uk also provides
information on fish health matters. NB Need to add a link to website where information is available.

To organise a fish health inspection on suspicion of an outbreak, contact the CEFAS Fish Health
Inspectorate on 01305 206673/74
or by sending an email to: fish.health.inspectorate@cefas.co.uk

This Designated Area Order (DAO) came into force on 7th June 2006.

Press enquiries 020 72384990; Public enquiries 08459 335577; Press notices are available on our website www.defra.gov.uk
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