Genetic positioning of aquabirnavirus isolates from cultured Japanese eel Anguilla japonica in Korea

Aquabirnavirus is an epizootic virus in Japanese eel Anguilla japonica farms in Korea, although its origin is unclear. In the present study, nucleotide sequences of the VP2/NS junction region of 9 Korean aquabirnaviruses from cultured eel in various areas of Korea during 2000-2009 were analyzed to evaluate their genetic relatedness to worldwide isolates. The nucleotide sequences showed more than 94.2% identity among the 9 Korean eel isolates, 71.2% identity among 16 Korean isolates from freshwater and marine fish, and 71.1% identity among 25 worldwide isolates. All 9 isolates in this study were phylogenetically classified into genogroup II, including isolates from Denmark, Spain, Taiwan and Japan, and were discrete from salmonid and marine fish isolates (genogroup I and VII) in Korea. These results suggest that the Korean eel isolates have most likely been introduced from outside the country and not from coastal areas of Korea.