Inter-laboratory proficiency tests to detect viral fish diseases.

An inter-laboratory proficiency test has ben provided by the European Community Laboratory (CRL) for Fish Diseases every year since 1996. The test is provided to all European National Reference Laboratories (NRLs) that are obliged to participate and to a limited number of non-European NRLs, making the total number of participating laboratories 35. The test is primarily designed to assess the ability of participating laboratories to identify and quantify the notifiable non-exotic fish pathogenic viruses: Viral haemorrhagic septicaemia virus (VHSV) and infectious haematopietic necrosis virus (IHNV) but also to assess their ability to differentiate other fish viruses as spring viraemia of carp virus, infectious pancreatic necrosis virus, perch rhabdovirus etc. Five coded ampoules are provided to participants containing lyophilised supernatant from infected cell cultures. The CRL collect the data and provide a statistically and graphically picture of the performance of the individual laboratory relative to other participants. The proficency test has been used for additional purposes. Participants have been asked to genotype virus isolates and have been encouraged to submit full-lengt G-gene sequences of the rhabdoviruses identified in order to analyse the inter-laboratory quality of sequencing results. Such results are very important for assessing how sequence data can be used in e.g. molecular tracing. Here we present results and experiences obtained from these additional studies.