The purpose of the study was to analyze alphavirus isolates collected in Uganda and Tanzania in the period preceding their global spread dating back to the middle of the last century. We supposed that analysis of their genomes could help to learn more about the specific features and the direction of molecular evolution of alphaviruses in the modern world. Archival samples of Chikungunya (CHIKV) and Semliki Forest (SFV) viruses were revived by cultivation in the Vero E6 cells. Isolates were identified by RT-PCR followed by sequencing. Whole genome sequences were obtained by NGS and used for phylogenetic analysis. The presence of two representatives of the Alphavirus genus, namely, CHIKV and SFV, was observed in the studied archival CHIKV sample. Only SFV was found in the archival sample from 1942. All isolates were capable of highly efficient replication in the C6/36, Vero E6, 293, and SPEV cell cultures showing the development of cytopathological effects and were able to produce pathomorphological changes typical of these alphaviruses in mice. Whole genome sequences have been obtained for these viruses and analyzed. Studied isolates clustered with the typical African CHIKV and SFV strains. These isolates may be attributed to the oldest known SFV and CHIKV strains dating back to 1942 and 1953 preserved in laboratory collections. The archival CHIKV isolate was genotyped as an ECSA variant, the modern representatives of which are associated with the global spread of CHIKV in recent decades. Semliki Forest and Chikungunya virus isolates were revived from archival laboratory samples presumably dating back to 1942 and 1953, and their virological characterization was carried out, followed by genotyping and phylogenetic analysis of their whole-genome sequences.

该研究的目的是分析在乌干达和坦桑尼亚收集的甲病毒分离株，这些分离株是在其全球传播之前的时期（可追溯到上世纪中叶）。我们认为对其基因组的分析有助于更多地了解现代世界甲病毒的具体特征和分子进化方向。基孔肯雅热 (CHIKV) 和塞姆利基森林 (SFV) 病毒的档案样本通过在 Vero E6 细胞中培养而得以复活。通过 RT-PCR 和测序鉴定分离株。通过NGS获得全基因组序列并用于系统发育分析。在所研究的 CHIKV 档案样本中观察到存在两种甲病毒属的代表，即 CHIKV 和 SFV。1942 年的档案样本中仅发现了 SFV。所有分离株均能够在 C6/36、Vero E6、293 和 SPEV 细胞培养物中高效复制，显示细胞病理学效应的发展，并能够产生这些细胞典型的病理形态学变化小鼠体内的甲病毒。已经获得了这些病毒的全基因组序列并进行了分析。研究了与典型非洲 CHIKV 和 SFV 毒株聚集在一起的分离株。这些分离株可能是实验室收藏中保存的最古老的 SFV 和 CHIKV 毒株，可追溯到 1942 年和 1953 年。存档的 CHIKV 分离株被基因分型为 ECSA 变种，其现代代表与近几十年来 CHIKV 的全球传播有关。塞姆利基森林病毒和基孔肯雅病毒分离株是从可能追溯到 1942 年和 1953 年的档案实验室样本中恢复的，并对其进行了病毒学表征，随后对其全基因组序列进行了基因分型和系统发育分析。