Ecological diamics of marine birnavirus in marine organisms and the environments in the Uwa Sea

本项目旨在阐明日本珍珠贝及其自然宿主的海洋伯纳病毒（MABV）的生态学，以及MABV在Uwa海的季节性发生。发现日本珍珠贝中MABV的感染情况在夏季和冬季有所变化。该病毒夏季以少量基因组和蛋白质感染血细胞，冬季向实质细胞扩散。冬季养殖牡蛎的病毒检出率明显提高。冬季海水中病毒检出率上升。Uwa海浮游植物中含有大量的Nitzchia spp，这些Nitzchia spp不能被牡蛎消化。这表明牡蛎的浮游生物饲料可能不足。MABV首先在淡水鱼Ayu中检测到，而在邻近地区的Amago鲑鱼中检测到另一种病毒IPNV。这表明海水是阿玉地区MABV的载体。本项目揭示了MABV的生态学、在珍珠贝中的感染状态、在不同寄主中的突变。

This project has aimed to clarify the ecology of marine birnavirus (MABV) in Japanese Pearl Oyster and natural hosts, and the seasonal occurrence of MABV in the Uwa Sea.The infection status of MABV in Japanese Pearl Oyster was found to change between summer and winter. The virus infected in haemocytes in summer with small amount of genome and protein, and then spread in winter into the parenchymal cells. Virus detection rate by PCR in the cultured oyster appeared to be increased in winter. Also the virus detection rate in seawater increased in winter season.The phytoplankton in the Uwa Sea contained much amount of Nitzchia spp., which could not be digested by the oyster. This suggests that the feed plankton of the oyster might be deficient.MABV was firstly detected in Ayu, fresh water fish, whereas Amago salmon in close area possessed another birnavirus, IPNV.This suggests seawater is a carrier of MABV in Ayu.This project revealed ecology of MABV, infective state in the pearl oyster, mutation in various hosts.