First detection of recombinant variant of African swine fever virus in the Russian Federation (brief communication)

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.