Fig. 1. Genome-wide map showing correspondence of sequences between ASF isolates ASFV/Primorsky_2023/DP-4560.Rec and ASFV/Pig/Jiangsu/LG_China/2021 (blue color shows homology between the sequences)
Иголкин Алексей Сергеевич - канд. вет. наук, заместитель руководителя лабораторно-диагностического центра, заведующий референтной лабораторией по африканской чуме свиней
мкр. Юрьевец, г. Владимир, 600901
Alexey S. Igolkin - Cand. Sci. (Veterinary Medicine), Deputy Head of the Laboratory Diagnostic Center, Head of Reference Laboratory for African Swine Fever
Yur’evets, Vladimir 600901
Чернышев Роман Сергеевич - аспирант, ветеринарный врач референтной лаборатории по африканской чуме свиней
мкр. Юрьевец, г. Владимир, 600901
Roman S. Chernyshev - Postgraduate Student, Veterinarian, Reference Laboratory for African Swine Fever
Yur’evets, Vladimir 600901
Зиняков Николай Геннадьевич - канд. биол. наук, ведущий научный сотрудник референтной лаборатории вирусных болезней птиц
мкр. Юрьевец, г. Владимир, 600901
Nikolay G. Zinyakov - Cand. Sci. (Biology), Leading Researcher, Reference Laboratory for Avian Viral Diseases
Yur’evets, Vladimir 600901
Морозова Елизавета Олеговна - аспирант, биолог референтной лаборатории по африканской чуме свиней
мкр. Юрьевец, г. Владимир, 600901
Elizaveta O. Morozova - Postgraduate Student, Biologist, Reference Laboratory for African Swine Fever
Yur’evets, Vladimir 600901
Шотин Андрей Романович - канд. вет. наук, научный сотрудник референтной лаборатории по африканской чуме свиней
мкр. Юрьевец, г. Владимир, 600901
Andrey R. Shotin - Cand. Sci. (Veterinary Medicine), Researcher, Reference Laboratory for African Swine Fever
Yur’evets, Vladimir 600901
Груздев Константин Николаевич - д-р биол. наук, профессор, главный научный сотрудник информационно-аналитического центра
мкр. Юрьевец, г. Владимир, 600901
Konstantin N. Gruzdev - Dr. Sci. (Biology), Professor, Chief Researcher, Information and Analysis Centre
Yur’evets, Vladimir 600901
Чвала Илья Александрович - канд. вет. наук, заместитель директора по НИР
мкр. Юрьевец, г. Владимир, 600901
Ilya A. Chvala - Cand. Sci. (Veterinary Medicine), Deputy Director for Research
Yur’evets, Vladimir 600901
Мазлум Али - канд. биол. наук
г. Батон-Руж, LA 70803
Ali Mazloum - Cand. Sci. (Biology)
Baton Rouge, LA 70803
As part of extensive molecular and genetic research into African swine fever virus isolates circulating in Russia, a recombinant variant with a mosaic genome structure has been identified. The one that caused an outbreak on a pig farm in the Primorsky Krai, in 2023. The characterized strain ASFV/Primorsky_2023/DP-4560.Recdemonstrates hemadsorption, active propagation in porcine primary macrophage cell culture, 99.9917% identity with the first recombinant isolates from the People’s Republic of China, recovered in 2021. Recombination sites included 79 open reading frames homologous to genotype II isolates; 49 ones homologous to genotype I and 12 mixed ones. Testing biomaterial from dead pigs in real-time polymerase chain reaction showed no changes in sensitivity or specificity, despite significant genetic distinctions between the recombinant and genotype II isolates that are enzootic to the Russian Federation. However, in 2023, D. Zhao et al. reported on high virulence of the virus related variants as revealed by the challenge tests in domestic pigs. Given the accelerating rates of AFSV molecular evolution in the East Asian countries (China, Vietnam and the Far Eastern regions of Russia), it is required to improve control measures, general and specific prevention, national and international surveillance over the economically significant animal disease.
В рамках проведения комплексных молекулярно-генетических исследований изолятов вируса африканской чумы свиней, циркулирующих в России, идентифицирован рекомбинантный вариант с мозаичной структурой генома, вызвавший вспышку заболевания на территории свинокомплекса Приморского края в 2023 г. Охарактеризованный штамм ASFV/Primorsky_2023/DP-4560.Rec обладал феноменом «гемадсорбции», высокой репродукционной активностью в первичных культурах клеток макрофагов свиней, 99,9917%-й идентичностью с первыми рекомбинантными изолятами из Китайской Народной Республики, выявленными в 2021 г. Сайты рекомбинации включали 79 открытых рамок считывания, гомологичных изолятам генотипа II, 49 – генотипу I и 12 смешанных. Исследование методом полимеразной цепной реакции в режиме реального времени биологического материала, ото[
In 2023, African swine fever situation (ASF) in Russia was unfavourable. The ASF outbreaks were detected in populations of wild boars and domestic pigs both in backyards and on commercial pig farms in a number of subjects of the Russian Federation.
As part of the research project implemented by the Federal Centre for Animal Health, ASF virus isolate (ASFV/Primorsky_2023/DP-4560.Rec), recovered from an outbreak reported on a commercial pig farm in the Primorsky Krai (in May 2023; Settlement Pervomayskoye, Raion Mikhailovsky), was subjected to a comprehensive sequencing and phylogenetic analysis.
The obtained results were compared with the data from the open sources describing isolates recovered in 2018–2023 in the Primorsky Krai and other subjects of the Russian Federation. As reference samples we used sequences of ASFV genotypes I and II strains from the GenBank international database (i.e. OURT 88/3 – No. AM712240.1 strain and Georgia 2007/1 – No. FR682468.2 strain, respectively), as well as sequences of recombinant isolates (genotypes I and II) detected during ASF outbreaks in 2021–2022 in domestic pigs in the Provinces of Hainan, Inner Mongolia and Jiangsu (China) [
During the research, we identified ASF virus that is able to accumulate in porcine bone marrow cell culture at a titer of (8.2 ± 0.23) lg HAD50/cm3, demonstrating the phenomenon of hemadsorption.
Genome-wide sequencing of ASFV/Primorsky_2023/DP-4560.Rec and ASFV/Pig/Jiangsu/LG_China/2021 (recombinant variant registered in China in 2021) isolates demonstrated 99.9917% homology (Fig. 1).
Results of the genome-wide comparison of phylogenetic trees given in Figure 2 clearly demonstrate correspondence of the studied virus from the Primorsky Krai to a separate clade of recombinant isolates from China (2021–2022).
Formation of the recombination sites (79 open reading frames (ORF) belong to genotype II, 49 to genotype I, 12 are mixed) in the genome of ASFV/Primorsky_2023/DP-4560.Rec strain are shown in Figure 3.
The recombinant variant described by D. Zhao et al. in 2023 was characterized as highly virulent for domestic pigs [
In 2023, the recombinant virus variant, similar to the previous ones, was detected in the northern provinces of Vietnam [
Currently, the Federal Centre for Animal Health researchers are studying biological properties of ASFV/Primorsky_2023/DP-4560.Rec isolate, testing its properties in susceptible animals as well. Primary data suggest that the genome changes do not affect sensitivity and specificity of real-time polymerase chain reaction, which is widely used to diagnose the disease. The results of further and ongoing experiments will be reported additionally.
Fig. 1. Genome-wide map showing correspondence of sequences between ASF isolates ASFV/Primorsky_2023/DP-4560.Rec and ASFV/Pig/Jiangsu/LG_China/2021 (blue color shows homology between the sequences)
Fig. 2. Phylogenetic tree of ASFV/Primorsky_2023/DP-4560.Rec (●) and other ASF virus strains
Fig. 3. Map of the annotated ORFs in ASFV/Primorsky_2023/DP-4560.Rec strain (ORFs with a high percentage of identity to genotype II sequence are given in purple; ORFs similar to genotype I are given in green; genes having sequence identical with genotype II, but mutations identical to genotype I are given in orange)
The data obtained re-confirm ASF transboundary nature, demonstrate vulnerability of the global pig industry and set up new requirements for vaccines being developed against this disease.
The authors declare that there are no conflicts of interest present.