Mazloum Ali, van Schalkwyk Antoinette, Shotin Andrey, Zinyakov Nikolay, Igolkin Alexey, Chernishev Roman, Debeljak Zoran, Korennoy Fedor, Sprygin Alexander V
Reference Laboratory for African Swine Fever Virus, FGBI "Federal Centre for Animal Health" (FGBI "ARRIAH"), Vladimir, Russia.
Agricultural Research Council - Onderstepoort Veterinary Institute, Pretoria, South Africa.
Front Vet Sci. 2023 Jan 5;9:1019808. doi: 10.3389/fvets.2022.1019808. eCollection 2022.
Since the first report of outbreaks of African swine fever (ASF) in Georgia in 2007, the disease has expanded into Europe, Russia, and Asia, spreading rapidly contact with infected animals including domestic pigs and wild boars. The vast expansion of this Genotype II African swine fever virus (ASFV) across wide-ranging territories and hosts inevitably led to the acquisition of novel mutations. These mutations could be used to track the molecular epidemiology of ASFV, provided that they are unique to strains restricted within a certain area. Whilst whole-genome sequencing remains the gold standard for examining evolutionary changes, sequencing of a single locus with significant variation and resolution power could be used as a rapid and cost-effective alternative to characterize multiple isolates from a single or related outbreak.
ASFVs obtained during active ASF outbreaks in the Russian region of Kaliningrad between 2017 and 2019 were examined. Since all of the viruses belonged to Genotype II and no clear differentiation based on central variable region (CVR) sequencing was observed, the whole-genome sequences of nine ASFV isolates from this region were determined. To obtain insights into the molecular evolution of these isolates, their sequences were compared to isolates from Europe, Asia, and Africa.
Phylogenetic analysis based on the whole-genome sequences clustered the new isolates as a sister lineage to isolates from Poland and Germany. This suggests a possible shared origin followed by the addition of novel mutations restricted to isolates from this region. This status as a sister lineage was mirrored when analyzing polymorphisms in MGF-505-5R and MGF-110-7L, whilst a polymorphism unique to sequences from Kaliningrad was identified at locus K145R. This newly identified mutation was able to distinguish the isolates obtained from Kaliningrad with sequences of Genotype II ASFVs available on GenBank.
The findings of this study suggest that ASFVs circulating in Kaliningrad have recently obtained this mutation providing an additional marker to the mutations previously described.
自2007年格鲁吉亚首次报告非洲猪瘟（ASF）疫情以来，该病已蔓延至欧洲、俄罗斯和亚洲，通过与包括家猪和野猪在内的受感染动物接触而迅速传播。这种II型非洲猪瘟病毒（ASFV）在广泛的地域和宿主中大规模传播，不可避免地导致了新突变的出现。只要这些突变是特定区域内毒株所特有的，就可用于追踪ASFV的分子流行病学。虽然全基因组测序仍是研究进化变化的金标准，但对具有显著变异和分辨能力的单个位点进行测序，可作为一种快速且经济高效的替代方法，用于鉴定来自单次或相关疫情的多个分离株。
对2017年至2019年俄罗斯加里宁格勒地区ASF疫情活跃期间获得的ASFV进行了检测。由于所有病毒均属于II型，且基于中央可变区（CVR）测序未观察到明显差异，因此确定了该地区9株ASFV分离株的全基因组序列。为深入了解这些分离株的分子进化情况，将其序列与来自欧洲、亚洲和非洲的分离株进行了比较。
基于全基因组序列的系统发育分析将新分离株聚类为波兰和德国分离株的姐妹谱系。这表明可能存在共同起源，随后出现了仅限于该地区分离株的新突变。在分析MGF-505-5R和MGF-110-7L的多态性时，这种姐妹谱系的地位得到了体现，同时在K145R位点发现了加里宁格勒序列特有的多态性。这一新发现的突变能够将从加里宁格勒获得的分离株与GenBank上可用的II型ASFV序列区分开来。
本研究结果表明，在加里宁格勒传播的ASFV最近获得了这一突变，为先前描述的突变提供了一个额外的标记。
