Comparison Of Titers Of Four Strains Of Duck Tembusu Virus In Different Cells And Analysis Of Whole-genome Sequencing Of Strain SX

Duck tembusu virus (DTMUV) is a novel infectious agent that caused severe eggdrop in duck and huge economic loss in duck-breeding industry. Afterphysicochemical properties and biological characteristics of the pathogen showed, thepathogen, belonging to the Flaviviridae, flavivirus genus, Ntaya virus, is envelopedpositive strand RNA virus. The complete genome is composed of11kb nucleotides (nt)with a single long open reading frame. It codes3structural proteins and7nonstructural proteins. In the begaining, the outbreaks happened in Jiangsu, Zhejiang, andShanghai. Then, spread rapidly to all of the southeast provinces of China, includingShandong, Beijing, Hebei, Fujian, Anhui, Guangdong, Guangxi and so on. Thedisease continued to transmit until winter, all the ducks raised in China were under ahuge threat by this unknown pathogen. To illustrate the molecular characteristics andgenome profiles of DTMUV, and help for the prediction and controlment of thedisease, we carried out a series of analysis of duck Tembusu virus.1. In this study, we do some research of this virus isolated from Shandong at2013showed that the virus identified as duck tembusu virus, namely SX. The deathrate of duckling which infected this virus is100%.2. In this study, we compared the adaptation of the isolate and several otherstrains in different host cells(CEF, DEF, DF1, BHK-21, VERO, MDCK), the resultssuggested that all strains are suitable for DEF, BHK-21. But in VERO cells, it mustblind3generation to adapt to this cell, and generate obvious CPE.In DF1cell culture,though no obvious CPE viewed, the RT-PCR method can detect viral nucleic acid.The new isolate SX is more adaptability to DEF, BHK-21, VERO cell than otherstrains. All strain can't apply to CEF and MDCK cells.3. Sequence analysis of the whole genome of SX showed that our strain shared a highest similarity with the DTMUV isolated at the same periods in other places;thepolyprotein shared more than88.7%nucleotides identity and more than99.2%aminoacid identity with these isolates, and shared56.9%to72.1%nucleotides identity withflavivirus group. Based on E, NS1genes of genetic evolution relationship analysis,We found that the E gene and NS1gene of DTMUV highly correlated with Tembusuvirus isolated form mosquito in Malaysia and Sitiawan virus isolated form commoditychicken in Malaysia, with amino acid identities more than93%.