Laboratory of Viral Hepatitis, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Rio de Janeiro, Brazil.
Laboratory of Viral Hepatitis, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Rio de Janeiro, Brazil.
Infect Genet Evol. 2024 Nov;125:105671. doi: 10.1016/j.meegid.2024.105671. Epub 2024 Sep 17.
Hepatitis D virus (HDV) is currently classified into 8 genotypes (1 to 8) and several subgenotypes, with distinct distribution worldwide. However, due to the scarcity of complete genome sequences in databases, this classification is constantly being updated and tends to be regularly revisited in upcoming years as more sequence data becomes available. Aiming to increase knowledge about the genetic variability of HDV, this study presents the full-length genomes of 11 HDV samples collected in Brazil in endemic and non-endemic regions, including the first complete genomes of the genotypes 5 and 8 obtained outside Africa. We also determined the co-infecting HBV genotypes to investigate their prevalence among the HDV-infected individuals throughout the country. Whole genome sequencing confirmed our previous findings based on a partial fragment of the HDV genome, in which HDV subgenoypes 3c (9/11; 81.8 %), 5b (1/11; 9.1 %) and one HDV-8 sequence (1/11; 9.1 %) were detected. As previously observed, HDV-8 formed a distinct branch apart from subgenotypes 8a and 8b, a monophyletic clade representing a novel HDV-8 subgenotype, designated as 8c. Among HDV-3 samples, the main co-infecting HBV genotype found was HBV-F (4/8; 50 %), reflecting the higher incidence of this native South American genotype in the endemic Amazon Basin. Both samples infected with HDV-5 and HDV-8 were coinfected with HBV genotype E, also a genotype with African origin. Our findings based on complete genome sequence of HDV corroborated our results based on a partial region of the HDV genome of a novel HDV-8 subgenotype and reinforced the need to use full-length genomes to properly subdivide genotypes with very low intragroup genetic variability, such as HDV-3. The provision of these complete genomes is expected to contribute to the enrichment of sequence databases for future molecular and evolutionary investigations of HDV.
丁型肝炎病毒 (HDV) 目前分为 8 个基因型 (1 至 8) 和几个亚型，在全球范围内分布广泛。然而，由于数据库中完整基因组序列的稀缺，这种分类不断更新，并且随着更多序列数据的出现，在未来几年内，这种分类往往会定期重新审视。本研究旨在增加对 HDV 遗传变异性的了解，呈现了在巴西流行和非流行地区收集的 11 个 HDV 样本的全长基因组，包括在非洲以外获得的基因型 5 和 8 的首个完整基因组。我们还确定了共同感染的 HBV 基因型，以调查它们在全国 HDV 感染者中的流行情况。全基因组测序证实了我们之前基于 HDV 基因组部分片段的发现，其中 HDV 亚基因型 3c (9/11; 81.8%)、5b (1/11; 9.1%)和一个 HDV-8 序列 (1/11; 9.1%)被检测到。与之前观察到的一样，HDV-8 与亚基因型 8a 和 8b 形成了一个独特的分支，是一个代表新的 HDV-8 亚基因型的单系分支，被指定为 8c。在 HDV-3 样本中，发现的主要共同感染的 HBV 基因型是 HBV-F (4/8; 50%)，反映了这种本土南美洲基因型在流行的亚马逊流域的较高发病率。感染 HDV-5 和 HDV-8 的两个样本都与 HBV 基因型 E 共同感染，这也是一种起源于非洲的基因型。我们基于 HDV 全长基因组序列的发现与我们基于 HDV 基因组部分区域的发现相符，证实了需要使用全长基因组来正确细分具有非常低组内遗传变异性的基因型，如 HDV-3。这些完整基因组的提供有望为未来 HDV 的分子和进化研究丰富序列数据库做出贡献。
