Institute for Biotechnology, São Paulo State University (Unesp), Botucatu 18607-440, Brazil.
Agrarian Sciences Institute (ICA), Vales do Jequitinhonha e Mucuri Federal University (UFVJM), Unaí 39803-371, Brazil.
Viruses. 2020 Feb 12;12(2):207. doi: 10.3390/v12020207.
Equine infectious anemia virus (EIAV) is a persistent lentivirus that causes equine infectious anemia (EIA). In Brazil, EIAV is endemic in the Pantanal region, and euthanasia is not mandatory in this area. All of the complete genomic sequences from field viruses are from North America, Asia, and Europe, and only proviral genomic sequences are available. Sequences from Brazilian EIAV are currently available only for and LTR regions. Thus, the present study aimed for the first time to sequence the entire EIAV genomic RNA in naturally infected horses from an endemic area in Brazil. RNA in plasma from naturally infected horses was used for next-generation sequencing (NGS), and gaps were filled using Sanger sequencing methodology. Complete viral genomes of EIAV from two horses were obtained and annotated (Access Number: MN560970 and MN560971). Putative genes were analyzed and compared with previously described genes, showing conservation in and genes and high variations in LTR and sequences. Amino acid changes were identified in the p26 protein, one of the most common targets used for diagnosis, and p26 molecular modelling showed surface amino acid alterations in some epitopes. Brazilian genome sequences presented 88.6% nucleotide identity with one another and 75.8 to 77.3% with main field strains, such as EIAV Liaoning, Wyoming, Ireland, and Italy isolates. Furthermore, phylogenetic analysis suggested that this Brazilian strain comprises a separate monophyletic group. These results may help to better characterize EIAV and to overcome the challenges of diagnosing and controlling EIA in endemic regions.
马传染性贫血病毒（EIAV）是一种持续性慢病毒，可引起马传染性贫血（EIA）。在巴西，EIAV 在潘塔纳尔地区流行，该地区不强制实施安乐死。所有来自北美的田间病毒的完整基因组序列、亚洲和欧洲，并且仅可获得前病毒基因组序列。目前，巴西 EIAV 的序列仅可用于 和 LTR 区域。因此，本研究首次旨在对来自巴西流行地区的自然感染马的整个 EIAV 基因组 RNA 进行测序。使用来自自然感染马的血浆 RNA 进行下一代测序（NGS），并使用 Sanger 测序方法填充间隙。获得并注释了来自两匹马的 EIAV 的完整病毒基因组（登录号：MN560970 和 MN560971）。分析了推定基因，并与先前描述的基因进行了比较，显示在 和 基因中保守，而在 LTR 和 序列中高度变异。在最常用于诊断的 p26 蛋白中鉴定出氨基酸变化，并且 p26 分子建模显示在一些表位中存在表面氨基酸改变。巴西基因组序列彼此之间具有 88.6％的核苷酸同一性，与主要田间毒株（如 EIAV 辽宁、怀俄明、爱尔兰和意大利分离株）具有 75.8％至 77.3％的同一性。此外，系统发育分析表明，该巴西株属于一个单独的单系群。这些结果可能有助于更好地表征 EIAV，并克服在流行地区诊断和控制 EIA 的挑战。
