Fu Fumei, Deng Qiaomu, Li Qiuhong, Zhu Weiyu, Guo Jinhan, Wei Ping
Institute for Poultry Science and Health, Guangxi University, Nanning, China.
Front Vet Sci. 2022 May 26;9:901292. doi: 10.3389/fvets.2022.901292. eCollection 2022.
Avian hepatitis E virus (HEV) is a major pathogen associated with hepatitis splenomegaly syndrome in chickens and has been reported in China. Phylogenetic trees, Bayesian analysis, positive selection sites screening, and recombination analysis were first used to comprehend the global avian HEVs. All the avian HEV strains, including a new isolate named GX20A1 got from Donglan Black chicken in Guangxi, China, were uniformly defined into four genotypes, and GX20A1, belongs to Genotype 3. The topology of the phylogenetic tree based on the sequences of a 339-bp fragment (coding the helicase) in open reading frame (ORF) 1 of the avian HEVs was consistent with that based on the full-genome sequence. The estimated evolution rate of avian HEVs is 2.73 × 10 substitution/site/year (95% confidence interval (): 8.01 × 10-4.91 × 10), and the estimated genetic diversity of the strains experienced a declining phase from 2010 to 2017 and stabilized after 2017. It was further found that the Genotype 3 HEVs, including isolates from Hungary and China, likely originated in the 1930s. Notably, GX20A1 was gathered in the same branch with a Genotype 3 Guangdong isolate CaHEV-GDSZ01, which appeared earlier than GX20A1. In addition, two positive selection sites were identified, one for each of ORF1 and ORF2. Overall, the study revealed that avian HEVs were uniformly defined into four genotypes, and a 339-bp fragment in ORF1 of the viral genome could be used for the classification. A Genotype 3 isolate GX20A1 was first found from Donglan Black chicken and most likely originated from Guangdong.
禽戊型肝炎病毒（HEV）是与鸡的肝炎脾肿大综合征相关的主要病原体，在中国已有报道。系统发育树、贝叶斯分析、正选择位点筛选和重组分析首次被用于了解全球禽HEV。所有禽HEV毒株，包括从中国广西东兰乌鸡中获得的名为GX20A1的新分离株，均被统一分为四个基因型，GX20A1属于基因型3。基于禽HEV开放阅读框（ORF）1中339bp片段（编码解旋酶）序列构建的系统发育树拓扑结构与基于全基因组序列构建的拓扑结构一致。禽HEV的估计进化速率为2.73×10-3替换/位点/年（95%置信区间：8.01×10-4-4.91×10-3），菌株的估计遗传多样性在2010年至2017年经历了下降阶段，并在2017年后趋于稳定。进一步发现，包括来自匈牙利和中国的分离株在内的基因型3 HEV可能起源于20世纪30年代。值得注意的是，GX20A1与一个基因型3广东分离株CaHEV-GDSZ01聚集在同一分支，该分离株出现时间早于GX20A1。此外，还鉴定出两个正选择位点，ORF1和ORF2各一个。总体而言，该研究表明禽HEV可统一分为四个基因型，病毒基因组ORF1中的339bp片段可用于分类。首次从东兰乌鸡中发现基因型3分离株GX20A1，最有可能起源于广东。
