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Establishing a scientific basis for the length of quarantine - FC1189

Council Directive 2006/88/EC (specifying requirements for the prevention and control of certain disease in aquatic animals) makes provision for the importation of wild aquatic animals of species susceptible to exotic or non-exotic diseases from any source not declared disease free, to be released in a farm or mollusc farming area provided that the animals are held in quarantine before release. Draft Commission Decision SANCO/1319/2008 laying down quarantine conditions specifies a minimum period of 60 days for fish and shellfish and 90 days for molluscs. At the end of the quarantine period the animals must be tested to demonstrate absence of the relevant disease. In the case of quarantine of wild aquatic animals the use of sentinel aquaculture animals susceptible to the relevant diseases is permitted so that the animals for import are not sacrificed for testing. However, the scientific basis for quarantine has not been demonstrated and raises the following:

1) Is the duration of quarantine too long or too short for all the relevant diseases? Should there be different durations for each disease?

2) What is the likelihood of carrier or latently infected aquatic animals expressing the pathogen such that it can be detected in their own tissues, or be transmitted to susceptible fish species? It is known that some such animals will only express the pathogen following stress or immunosuppression.

3) What will be done if susceptible fish are not available (e.g. wrong time of year) when the animals for import are ready to be quarantined?

Initially in the project the literature on carrier fish, sub-clinical and latent infections with regard to the exotic and non exotic listed in the Council Directive will be reviewed with the aim of:

1) Determining the likelihood that pathogens can be detected in such animals at the end of the quarantine period.

2) Determining the likelihood that pathogens can be transmitted to sentinel animals during the quarantine period and be detected in them at the end of the period.

Trials with fish that are subclinically or latently infected with selected pathogens will be undertaken to generate scientific data where it is lacking. Initially the test systems is likely to include carp subclinically infected with KHV or SVCV, or rainbow trout that are carriers of VHSV or IHNV. The precise test system will be determined by Defra priorities when that phase of the work commences. In addition the project will explore the use of an alternative to the use of aquaculture animals as a susceptible species. Initially we will use the stickleback, Gasterosteus aculeatus, and we will determine its susceptibility to some of the most important exotic and non exotic pathogens. That species has been selected because it has a short life-cycle and can be easily bred in captivity (there are already breeding populations at Cefas used in other projects), it tolerates a wide range of salinity and freshwater conditions and temperatures. Furthermore, it is known to be susceptible to VHSV and to a virus similar to EHNV.

The project aims to provide sound scientific data on which to base quarantine conditions for certain diseases, and provide information on the risks presented by the current recommendations.
Project Documents
• EVID4 - Final project report : FC1189 EVID4 Final Report   (342k)
Time-Scale and Cost
From: 2009

To: 2012

Cost: £303,052
Contractor / Funded Organisations
Animal Diseases              
Fish Disease              
Fish Health              
Fields of Study
Fish Health and Aquaculture