Isolation and Identification of Shandong Strain of Duck Tembusu Virus
In order to identify the prevalence status and variation of duck Tembusu virus(DTMUV)in Shandong Province,the clinical samples delivered from Tai'an,Jining and Zibo during the second half of 2018 to the first half of 2019 were detected for DTMUV,and virus isolation and identification were carried out towards the positive samples,then the whole genome sequences of the isolates were analyzed. The results showed that 8 out of 102 samples were positive,with the detection rate of 7.8%,from which,3 strains of DTMUV were isolated;the full lengths of all the three strains were all 10 993 bp,the amino acid homology of they ranged from 99.2% to 99.3%,and the homology between the isolates and 24 reference strains ranged from 95.8% to 99.9%,all the isolates fell into Chinese strain I;compared to the reference strains,the homologies of nucleocapsid protein C,envelope protein E and non-structural protein NS1 of the isolates were lower,which were 86.1% to 99.2%,95% to 99.4% and 92.3% to 99.7%,respectively,and with different number of amino acid mutation sites,but major protein structures and potential glycosylation sites had no difference. It was concluded that DTMUV was still prevalent in some regions in Shandong Province,which should be further concerned and studied,although its genetic structure and pathogenicity remained unchanged compared to the classical strains.