DAO 50:211-217 (2002)  -  doi:10.3354/dao050211

Detection of marine birnavirus in the Japanese pearl oyster Pinctada fucata and seawater from different depths

Shin-Ichi Kitamura1, Yuji Tomaru2, ZenĀ¹ichiro Kawabata3, Satoru Suzuki1,*

1Center for Marine Environmental Studies, Ehime University, Matsuyama 790-8577, Japan
2National Research Institute of Fisheries and Environment of Inland Sea, Ohno, Hiroshima 739-0452, Japan
3Center for Ecological Research, Kyoto University, Otsu 520-2113, Japan
*Corresponding author. E-mail:

ABSTRACT: This study examines the seasonal changes of marine birnavirus (MABV) in seawater and the Japanese pearl oyster Pinctada fucata reared at different depths (2 and 15 m). Oysters and seawater were collected in 1998, and a 2-step PCR was carried out to detect MABV. Virus isolation was performed on the PCR-positive samples in the oyster. The detection rate of the MABV genome in the oyster was low during June, but increased after July at both 2 and 15 m depths. MABV was not isolated until after September, when isolation rates of 10 to 28.6% were recorded. The results suggest that growth of MABV in the oyster is similar at 2 and 15 m depth. In contrast, the MABV genome in seawater was present through the year at 15 m depth, but was not detected in summer at 2 m. This suggests that the virus is destroyed by UV and/or other factors at 2 m in summer, but is stable in deeper waters.

KEY WORDS: Birnavirus · Japanese pearl oyster · Uwa Sea · Seawater · Depth

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