目的 分析2019年青岛市从3例有摩洛哥旅行史甲型肝炎(甲肝)病例中检测到的甲肝病毒(Hepatitis A virus,HA V)株基因特征和感染来源.方法 对甲肝病例进行流行病学调查,采集急性期血清标本并提取HAV核酸,采用巢式RT-PCR扩增和/或拼接HAV VP1-2A区和近全基因组核苷酸序列并构建系统进化树,分析本研究HAV与GenBank中参考株的核苷酸和氨基酸同源性以确定基因型,分析主要中和抗原表位关键氨基酸位点突变和基因重组.结果 3例甲肝病例在发病潜伏期内有摩洛哥旅行史和半生食贝类海产品史,并检测到HAV核酸.3株HAV均位于系统进化树的ⅠA基因亚型欧洲分支,且在VP1-2A区与ⅠA亚型参考株的核苷酸和氨基酸差异分别仅为0.29％-7.45％和0.00％-2.59％;病例1感染的HAV与2018年爱尔兰分离株18IRL89195近全基因组的核苷酸序列同源性最高(98.41％),仅在编码区的3D区第80位(V/L)和第372位(K/R)氨基酸不同.病例2和病例3感染的HAV近全基因组序列完全相同,与2016年法国污水分离株G22-029的核苷酸和氨基酸同源性最高,分别为99.85％和100％.未发现3株HAV存在主要中和抗原表位关键氨基酸位点突变和基因重组.结论 本研究HAV毒株属于ⅠA基因亚型,推测为境外感染且可能与半生食贝类海产品有关.
Genetic characteristics of hepatitis A virus strains detected in three hepatitis A cases with a history of travel in Morocco;Qingdao,2019
Objective To analyze genetic characteristics and sources of hepatitis A virus(HAV)strains detected in three hepatitis A cases in Qingdao in 2019 who had a history of travel in Morocco.Methods We conducted an epidemiological investigation of hepatitis A cases,collected acute serum samples,and extracted HAV nucleic acid.We used nested RT-PCR to amplify and/or splice nucleotide sequences of the HAV VP1-2A region and near-whole genome to construct phylogenetic trees.We compared nucleotide and amino acid homologies between the HAV strains and GenBank reference strains to determine genotype;we analyzed mutations at key amino acid sites of major neutralizing antigen epitopes and gene recombinations.Results The three hepatitis A cases had a history of travel to Morocco and a history of consuming half-cooked shellfish seafood during the putative incubation period;all were positive to HAV nucleic acid.The constructed phylogenetic tree showed that the three strains were located in the European branch of subgenotype ⅠA,with nucleotide and amino acid differences in VP1-2A regions of 0.29％-7.45％and 0.00％-2.59％,respectively,compared with subgenotype ⅠA reference strains.The strain from the first case had the highest near-whole genome sequence homology of 98.41％compared with the 2018 Irish strain 18IRL89195,with amino acids differing at the 80th(V/L)and 372nd(K/R)sites of the 3D coding region.Strains from the second and third cases had identical near-whole genome sequences and had the highest nucleotide and amino acid homologies at 99.85％and 100％compared with the 2016 French sewage strain,G22-029.No mutations at key amino acid sites of major neutralizing antigen epitopes or gene recombination were found in the three HAV strains.Conclusions The HAV strains in this study belong to subgenotype ⅠA,which we speculate to be from infection overseas due to consuming half-cooked shellfish seafood.
Hepatitis A virusGenotypeSubgenotypeGenetic characteristics
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