Detection of a Marine Birnavirus in Wild Molluscan Shellfish Species from Japan.

Thirteen wild molluscan shellfish species collected from 8 Prefectures in Japan were surveyed for the presence of marine birnavirus (MABV) by the polymerase chain reaction (PCR) technique and culture method. Approximately 60% of bivalves and 35% of gastropods tested had detectable MABV genome, although the prevalence of positive specimens varied among species. The PCR-positive shellfish were submitted to virus isolation. The isolation rate was low, suggesting that the MABV was in a state of persistent infection in these shellfish. Seventy four % of the examined virus strains were different in a position of the nucleotide sequences of the PCR products from that of MABV strains obtained from fish.