Ostreid herpesvirus-1 (OsHV-1) infections have been reported around the world associated with mortalities of the Pacific oyster, Crassostrea gigas. Recently, a new genotype called OsHV-1?var was described associated with important mortalities of C. gigas in France and has been considered a dangerous emerging pathogen for oysters. In the present work we describe for the first time the presence of this new genotype OsHV-1?var in Spain associated to mortalities of C. gigas. Moreover, we have developed a specific polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) assay to identify OsHV- 1?var and distinguish it from the reference herpesvirus genotype. We propose this technique as a useful method to provide a rapid identification of the OsHV-1?var in epizootiological studies and disease control programmes.
