Herpesvirus infections have been reported in different bivalves species around the world. Specific diagnostic tools are needed in order ta assess the causative raIe of these agents in mortalities observed among bivalves There is currently a lack of information concerning the occurrence of bivalve herpesviruses. This is probably due ta the lack of suitable diagnostic tools. The basic method for examination of bivalve samples is predominantly histology. This enables the identification of any cellular changes, but is not conclusive for virus identification. Transmission electron microscopy is a necessity for visual confirmation of viral infections. However, histology and electron microscopy are time consuming and inadequate for epidemiological studies. The aim of the VINO project is therefore the development and the validation of molecular, immunological and cellular tools for the diagnosis of, and studies on, bivalve herpesviruses. They should be applicable for identification of viruses during disease outbreaks. Moreover, these techniques must also be suitable for the detection of subclinical or latent viral infections. The specific aim of the programme is to develop specific tools for diagnosing herpesvirus infections in bivalves and to validate tools and reagents by using them in European laboratories involved with epidemiological surveys. The specific objectives are: 1 - Obtaining the complete oyster herpesvirus (OsHV-1) DNA sequence with determination of the genome structure. 2 - Comparing OsHV -1 with viruses belonging to the Herpesviridae family on the basis of sequence data and genome structure. 3 - Developing molecular tools for OsHV -1 detection. 4 - Developing immunological tools for OsHV -1 detection. 5 - Developing cellular tools for OsHV -1 detection using oyster primary cell cultures and vertebrate cell lines. 6 - Application of developed diagnostic tools for OsHV -1 detection in oyster samples from different geographical locations.