广州地区2012年1、2型登革病毒基因型特征研究

Genotyping of dengue virus type 1 and 2 strains isolated in Guangzhou area,2012

目的测定广州市2012年1、2型登革病毒（DENV1、DENV2）的E基因序列，探讨其来源及基因型。方法收集广州市2012年478例登革热患者急性期血清478份，用C6／36细胞培养分离登革病毒，RT—PCR法扩增全长E基因，测定序列并绘制系统发育树，结合流行病学资料进行分子流行病学分析。结果478例患者标本中分离到DENV16株，DENV22株，测序获得E基因序列，E基因长度均为1485bp，编码495个氨基酸，DENV1碱基同源性为97．4％～99．9％，推导的氨基酸同源性为99．2％～100．0％，其同源性与2011、2006和2004年份的国内DENV1流行株接近。DENV2碱基同源性为91．3％，推导的氨基酸同源性为97．8％，其同源性与我国DENV2流行株相对较远。进化分析发现，DENV1均属于同一亚型，即亚洲型，DENV2属于两个亚型，即马来西亚／印度次大陆和东南亚型。结论推测广州市2012年DENV1和DENV2均为输入性，DENV1可能由柬埔寨和广东佛山输入，DENV2可能由孟加拉国和缅甸输入。

To analyze the Envelope （E） gene of type 1, 2 dengue virus （DENV 1, DENV 2） isolated from Guangzhou in 2012 and to investigate the infection source and virus genotype, 478 serum samples were collected from 478 patients in acute phase of dengue fever. Dengue virus was cultured and isolated by C6/36 cells. Whole length E gene was amplified by reverse transeriptase-polymerase chain reaction （RT-PCR）, and then sequenced. The phylogenetic tree was drawn by neighbor-joining method. Both data on epidemiologic and molecular studies were processed and analysed. Six strains of DENV 1 and two strains of DENV 2 were isolated from samples of the 478 patients. The E gene sequence of these strains was obtained by sequencing. Both of DENV 1 and 2 E were 1 485 bp in length, encoding 495 amino acids. Nucleotide sequence homology of six strains DENV 1 was between 97.4%-99.9%, and the deduced amino acids sequence homology was between 99.2%-100.0%, whose strains＇ homology was very close with DENV 1 virus epidemic strains in 2011, 2006 and 2004 in China. DENV 2 nucleotide se- quence homology was 91.3%, and the deduced amino acids sequence homology was 97.8%, whose strains＇ homology was rela- tively distant with DENV 2 virus epidemic strains in China. The phylogenetic analysis showed that DENV 1 belonged to one genotype （Asian） in common, and DENV 2 belonged to two genotypes （Malaysia/India subcontinent and Southeast Asia）. It＇s presumed that all strains of DENV 1 and 2 in Guangzhou in 2012 are imported. DENV 1 may originate from the Cambodia and Foshan, China. DENV 2 viruses may originate from the Bengal and Burma.