Full-length genomic sequences of new subtype 1g hepatitis E virus strains obtained from four patients with imported or autochthonous acute hepatitis E in Japan
Full-length genomic sequences of new subtype 1g hepatitis E virus strains obtained from four patients with imported or autochthonous acute hepatitis E in Japan
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DOI：
10.1016/j.meegid.2017.10.007
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发表时间：
2017-11-01
影响因子：
3.2
通讯作者：
Okamoto, Hiroaki
中科院分区：
文献类型：
--
作者：
Nishizawa, Tsutomu;Primadharsini, Putu Prathiwi;Okamoto, Hiroaki
戊型肝炎病毒（HEV）在世界范围内引起人类急性或慢性肝炎，并可通过粪-口途径传播。从日本输入（来自巴基斯坦或印度）或本地急性戊型肝炎患者中获得的4株HEV（HE-JA 14 -2173、HE-JA 15 -1335、HE-JA 15 -1920和HE-JA 16 -0610）与尼泊尔和蒙古的基因型1 HEV株在部分ORF 2序列内的未指定亚型最密切相关。为了研究基因型1的一个假定的新亚型（1g）是否可以分配，全长基因组序列测定的四个戊型肝炎病毒株。它们在整个基因组上的核苷酸同源性为95.4-99.2%，与已报道的亚型1a-1f的HEV株的核苷酸同源性为6.3-11.7%，与未指定亚型的蒙古1型HEV株（MNE 15 -072）的核苷酸同源性仅为0.6-4.7%。系统进化分析表明，该4株戊型肝炎病毒与MNE 15 -072形成一个聚类，自举值为100%。虽然1a和1f亚型之间的p-距离为0.048-0.083，但这5株病毒与1a-1f亚型的1型HEV株的核苷酸p-距离值较高，为0.068-0.138。BLAST检索显示，至少在其他五个国家（包括法国、以色列、荷兰、葡萄牙和英国）存在1g亚型HEV的候选成员，在294-867个核苷酸的共同序列内与HE-JA 16 -0610株具有95.4-99.6%的同一性。这些结果支持在基因型1内分配一个新的亚型1g，并表明亚型1g菌株的全球分布。在欧洲发现的1g亚型菌株可以从亚洲进口。需要进一步的研究来证实HEV亚型1g的全球分布。
Hepatitis E virus (HEV) causes acute or chronic hepatitis in humans worldwide and can be transmitted via the fecal-oral route. Four HEV strains (HE-JA14-2173, HE-JA15-1335, HE-JA15-1920 and HE-JA16-0610) obtained from patients with imported (from Pakistan or India) or autochthonous acute hepatitis E in Japan were most closely related to the Nepalese and Mongolian genotype 1 HEV strains of unassigned subtype within the partial ORF2 sequence. To investigate whether a putative novel subtype (1g) of genotype 1 can be assigned, full-length genomic sequences were determined for the four HEV strains. They shared 95.4-99.2% nucleotide identity over the entire genome, and differed by 6.3-11.7% from the reported HEV strains of subtypes 1a-1f and by only 0.6-4.7% from a Mongolian genotype 1 HEV strain (MNE15-072) of unassigned subtype. A phylogenetic analysis showed that the four HEV strains obtained in the present study formed a cluster with MNE15-072, with a bootstrap value of 100%. Although the p-distance between subtypes 1a and 1f was 0.048-0.083, these five strains showed a higher nucleotide p-distance value of 0.068-0.138 with the genotype 1 HEV strains of subtypes 1a-1f. A BLAST search revealed the presence of candidate members of subtype 1g HEV in at least five other countries, including France, Israel, the Netherlands, Portugal, and the UK, sharing identities of 95.4-99.6% with the HE-JA16-0610 strain within the common sequence of 294-867 nucleotides. These results support the assignment of a new subtype 1g within genotype 1 and suggest a global distribution of subtype 1g strains. Subtype 1g strains found in Europe can be imported from Asia. Further studies are needed to confirm the global distribution of HEV subtype 1g.