Comparative analysis of scallop Chlamys farreri infected by acute viral necrosis virus( AVNV) in two areas

Acute viral necrosis virus(AVNV),which caused mass mortality of scallops Chlamys farreri,is a DNA virus. In the present study,the detection of AVNV was conducted on culture scallops from different culture modes and seeds to search appropriate culture modes and seeds which could reduce mortality of culture scallops. Ten adult scallops were sampled regularly from scallop single-cultured system( Liuqing River,Qingdao) and scallop-kelp co-cultured system( Sanggou Bay,Rongcheng) per month,both contained scallops originating from wild-seed and artificial-seed(March 2010- April 2011,total 480 scallops were sampled). The scallops were taken to the lab at low tempreture. Mantle tissue DNA was extracted and used as the template for nest-PCR to evaluate infection of AVNV. The results show ed that the infection rates of AVNV for cultured scallops from wild-seed and artificial-seed were 21.1% and 18.9% in Liuqing River, while in Sanggou Bay the infection rates were 11.1% and 5.6%. In both sampling sites,high infection rates were detected in July and August. Highest infection rate in Liuqing River reached 80%,while in Sanggou Bay that was only 40%. The present study indicated that scallop-kelp co-cultured system and artificial-seed could effectively decrease the infection rate of AVNV,which could be useful methods to control occurrence of scallop disease.