Abstract
Marine birnavirus (MABV) is a member of Aquabirnavirus and an opportunistic pathogenic virus in eukaryotic marine organisms. This virus has a broad host range in wild and cultured fish and shellfish. In this study, the distribution of MABV in seawater from different areas was examined by PCR of the VP2/Ns junction region of the MABV genome. We have detected the MABV genome in three marine water columns; off the coast of Japan, in the Pacific Ocean and in the Mediterranean Sea, suggesting that MABV is widely distributed. The MABV genome was also detected in samples of zooplankton from the Pacific Ocean. A high nucleotide sequence similarity (more than 98.5%) was observed among the PCR products from MABV genomes. Such a prevalent distribution of genetically similar MABV suggests that birnavirus is one of the components of the RNA pool in ocean environments.
