济南市两株输入性登革热3型病例病毒基因组全序列测定及分析OA北大核心CSTPCD

This study was aimed at identifying the serotypes and genotypes of two dengue fever virus strains isolated from two imported cases of dengue fever in Jinan city;obtaining their whole genome sequences;and analyzing their molecular evolu-tionary characteristics.Whole blood samples from two suspected positive cases of dengue fever in Jinan city were collected,and the subtypes were identified by real-time PCR.Serum samples were collected to detect dengue virus IgM and IgG antibodies,and NS1 antigen,though the colloidal gold method.Viral whole genome fragments were amplified and sequenced,and com-pared against reference sequences of viruses isolated in China and other countries.Phylogenetic trees were constructed in Mega 7.0 software,and gene recombination analysis was performed in RDP4 software.The viruses isolated from whole blood samples were identified as dengue virus type Ⅲ.Colloidal gold tests indicated that the suspected dengue fever cases were positive for NS1 and negative for IgG.The two complete genomes were sequenced and found to be 10 707 nt and 10 706 nt.The two se-quences differed in only 6 nucleotides.On the basis of phylogenetic analysis,these two virus strains were grouped into Dengue virus type 3 genotype 1,and were found to have high homology and close relationships with the 2017 Bangladesh genome.Sur-veillance of imported cases should be strengthened to prevent and control dengue fever epidemics.