Study On Biological Characteristics And Genome Analysis Of Duck Tembusu Virus FSD1Strain

The first outbreak of duck Tembusu virus (DTMUV) disease occurred in China in2010. Itsemergence and rapid spread have caused great economic loss for the duck industry, so thedisease is one of the major duck diseases in China. In this papar, biological characteristics,genome sequencing and evolution analysis of DTMUV FSD1strain were studied.The FSD1strain of DTMUV was isolated from infected ducks in Shandong province in2012. Biological characteristics indicated that this virus failed to cause red blood cellagglutination in chicken, duck, goose, pigeon and pig. Furthermore, this virus was sensitiveto chloroform, acid and heat. Under an electron microscope, the virus was found that it wasround or oval in shape with a diameter size of about50nm. The virus could grow well inDEF cell not in CEF cell after the strain was subjected to blind passage of three generations.Animal regression test results in young ducks showed that the typical symptoms and lesionsof this disease could be manifested as before.The whole genome of this virus was sequenced and analyaed, the results indicated that thewhole genome of FSD1was10,990nt in length, with an open reading frame (ORF) of10,230nt in length encoding a polyprotein3,410amino acids. The5' untranslated region (UTR) was142nt in length and the3' UTR was618nt in length. The polyprotein contained ten proteins,including three structural proteins (C, PrM and E) and non-structural proteins (NS1, NS2A,NS2B, NS3, NS4A, NS4B and NS5). Comprehensive forecast analysis showed that E Proteinof FSD1had18glycosylation sites. The E protein space structure simulation results showedthe E protein contained three functional areas: the first two ?a nd ?areas were partlydiscontinuous, but ?th area was successional in structure.Homology analysis results showed that FSD1had highest homologies with duck Tembusu viruses,followed by Bagaza virus. In terms of E genotyping, FSD1isolate belonged to ?b genotype. E geneticevolutionary tree of amino acids found all new domestic duck tembusu isolates and Bagaza isolates had thenearer genetic distance, in a larger branches, which was consistent with amino acid homology analysisresults of the whole genome.