Molecular Epidemiology About White Spot Syndrome In Jiangsu Province

White Spot Syndrome firstly outbreak in Taiwan of China early 90s of last century, then spread rapidly throughout Asia and Europe, causing a great loss. With the outbreak of trends, performing short duration and high mortality.3～10 d after the onset, most of the shrimp die, some shrimp ponds can reach 100% mortality. And as pathogenic variation, with the breeding capacity increases, the farming environment has deteriorated, the difficulty of its prevention and control also increases.White spot syndrome virus of shrimp is causing a major outbreak of epidemic pathogens. It's a large double-stranded DNA virus, belonging to thread virus family (Nimaviridae), and it is the only member of the Section. So far three total WSSV genome sequences published in GenBank, respectively, plants in Thailand, China Taiwan strain, and the Chinese mainland strain. Thailand strain sequence length is 292 967bp, the Chinese mainland strain sequence length is 305 107 bp, full-length gene sequences of China Taiwan strain is 307 287 bp.During winter of 2009 to autumn of 2010, we collected a total 548 shrimp from Lianyungang, Yancheng, Taizhou, and Nanjing and Xiamen. And then detected the white spot syndrome virus by nested PCR, the results showed that 98 samples from 548 shrimp have white spot syndrome virus, and the white spot syndrome virus-positive detection rate was 17.88%. Survey shows that the incidence of white spot syndrome virus in Jiangsu province is high.From the isolated strains of white spot syndrome virus, selected 3 genes encoding membrane protein VP19, VP24, VP28and a gene encoding the nucleocapsid protein VP35, and then designed primers according to the complete gene sequences of China strain, cloned and sequenced, analyze the differences in gene sequence between those strains.Compare the differences in volatile areas in white spot syndrome virus (WSSV) isolates in Thailand (TH strain), Chinese strain (CN strain), and China Taiwan strain (TW strain), and then design primers, amplify volatile area of these strains by PCR, cloned these isolates. Compare the sequence by MEGA4.0 and CloneManager software and draw phylogenetic tree, and analyze the variable region between different strains of features, the results show that changes in volatile areas show the evolution of WSSV.