The recent description and characterization of several novel and unique lumpy skin disease virus (LSDV) strains have revealed the inadequacy of current techniques for differentiating between vaccine- and wild-type viruses. The lack of reliable sequencing targets for promptly distinguishing circulating recombinant vaccine-like strains (RVLSs) highlights the need to develop a single and simple differentiation tool. In this study, we analyzed the available LSDV whole-genome sequences and identified a 705-bp region in open reading frame (ORF) LW134. Based on a single run of nucleotide sequencing and phylogenetic analysis, the region with 13 informative single nucleotide polymorphisms (SNPs) was capable of accurately segregating the novel RVLSs into the same five clusters previously confirmed by whole-genome sequencing. In addition, archived RVLSs from Russia were analyzed for further characterization using the newly described single PCR and sequencing assay. The ORF LW134 assay identified one archived RVLS as a novel cluster distinct from the previously described five clusters, while clustering the remaining samples into previously designated lineages, demonstrating the reliability of the assay. The novel PCR and sequencing assays described in this study have great potential for accurately delineating the molecular and evolutionary affiliation of circulating RVLSs.

Having spanned thousands of kilometers from Africa through Europe, the Middle East, Central Asia through to the south eastern part of Eurasia in the recent decade, lumpy skin disease virus has now become entrenched in China, Thailand, Vietnam, and South Korea. In light of discovered findings on recombination, cluster 2.5 lineage strains are now dominant and continue to spread throughout Southeast Asia. To gain a better picture of the phylogenetic landscape in the field, whole genome sequencing of 11 LSDV isolates from Russia and Mongolia collected from 2021 to 2023 has been attempted to see the dynamics of recombination signals, as was shown for LSDV circulating in 2017–2019 in Russia and Kazakhstan. Deep sequencing performed direct from skin nodules along with data retrieved from Genbank provides the most recent update on molecular epidemiology of LSDV and demonstrates that no more mosaic variant of LSDV has been observed, and cluster 2.5 lineage is now the dominant lineage currently on the rise in the region with its own patterns of monophyletic evolution. These discoveries may help future investigations aimed at epidemiological surveillance and virus tracking in the context of currently identified lineages worldwide.

Sheeppox (SPP) is a transboundary infectious disease that affects sheep and goats, leading to significant losses in countries with extensive small ruminant breeding programs. While sporadic SPP outbreaks have been observed in the Russian Northern Caucasus and the Far East, the number of SPP outbreaks in the Russian Central and Far East regions has increased recently. However, there is a lack of epidemiological data on SPP virus (SPPV) in the Northern latitudes. In this study, we conducted epidemiological and genetic analyses of SPP outbreaks in Russia from 2013 to 2021 using whole-genome sequences of five selected isolates. The epidemiological data revealed an elevated risk of SPP outbreaks during the summer months, although outbreaks were not limited to this period. A phylogenetic analysis of the whole-genome sequences of selected SPPVs obtained directly from clinical samples revealed a unique cluster of SPPV isolates circulating in Central Russia, which was related to previous isolates from the European part of Russia. In contrast, SPPVs obtained from the Russian Far East showed genetic similarity to isolates detected in Southeast Asia. The whole-genome sequences demonstrated that the reported outbreaks were not related to the NISKHI vaccine strain, which was used to combat lumpy skin disease and SPP in Russia. Based on the study findings and GenBank data, we propose a novel cluster designation system for SPPV genomic sequences.

Lumpy skin disease (LSD) is an emerging transboundary and highly infectious viral disease mainly affecting cattle. The fact that it was initially confined to Africa and then spread beyond its geographical range to other regions, including the Middle East, Turkey, Europe, the Balkans, Russia and Asia, is an indication of the underestimation and neglect of this disease. Vaccination is considered the most effective way to control the spread of LSDV, when combined with other control measures. LSD is now on the rise in Southeast Asia, where the circulating virus belongs to recombinant lineage 2.5. In this study, we evaluated the efficacy of an attenuated LSDV strain belonging to the Neethling cluster 1.1 by challenge with a virulent recombinant vaccine-like LSDV isolate “Mongolia/2021” belonging to cluster 2.5. Some of the vaccinated animals showed an increase in body temperature of 1–1.5 °C above the physiological norm, without clinical signs, local reactions, vaccine-induced viremia or generalization, demonstrating the efficacy and safety of the vaccine strain against a recombinant strain. Furthermore, all the vaccinated animals showed strong immune responses, indicating a high level of immunogenicity. However, the control group challenged with “Mongolia/2021” LSD showed moderate to severe clinical signs seen in an outbreak, with high levels of virus shedding in blood samples and nasal swabs. Overall, the results of the present study demonstrate that the attenuated LSDV Neethling strain vaccine has a promising protective phenotype against the circulating strains, suggesting its potential as an effective tool for the containment and control of LSD in affected countries from Southeast Asia.

Sheep pox (SPP) constitutes a global animal health scourge, despite the numerous efforts targeting the eradication of the disease implemented in affected countries. An efficient control and eradication strategy incorporates the use of live attenuated vaccines, which in turn requires a method for differentiation between vaccinated and infected sheep. The NISKHI live attenuated SPP vaccine (LAV) is abundantly used in Russia, Kazakhstan and other Central Asian countries. This study describes the development and evaluation of a real-time PCR with a high-resolution melting assay, capable of differentiating the NISKHI vaccine virus from circulating virulent field strains. The RNA polymerase subunit RPO132 gene contains a unique single nucleotide polymorphism (SNP) capable of altering the melting curves of amplicons from LAV and virulent field isolates circulating in the region. The melting temperature (Tm) of field isolates ranged from 75.47 °C ± 0.04 to 75.86 °C ± 0.08, while the vaccine strain averaged 76.46 °C ± 0.12. Subsequent evaluation of this assay demonstrated that the recent SPP outbreaks in central Russia may be attributed to virulent field isolates. This robust assay was proven to consistently and differentially detect the NISKHI LAV strain when analyzing clinical samples from affected sheep.

Studying the agents of bovine viral diarrhea (BVD) is an important task given the high probability of new isolate introduction into the Russian Federation, as well as the need to take into account the genotype and subgenotype of the virus circulating in a herd when developing vaccines and diagnostic kits for the infection. During the work performed, 6 BVD virus isolates were recovered and identified. The recovery of these isolates in the lamb testicle cell subculture revealed that Bashkiria/2019, Kirov/2020 and Samara/2020 isolates belong to non-cytopathic bovine viral diarrhea virus biotypes, Chelyabinsk/2021 isolate demonstrated the characteristic cytopathic effect in the monolayer and was classified as a cytopathic variant of thevirus, the adaptation of Belgorod/2021 and Udmurtiya/2020 isolates to this cell system was not possible. The study also identified the species of the recovered isolates. Based on the analysis of the nucleotide sequence of genome 5’-untranslated region (5’-UTR) fragment, these isolates were classified as belonging to three genotypes of the virus. The phylogenetic analysis showed that Chelyabinsk/2021 and Udmurtiya/2020 isolates belong togenotype2 and demonstrate, respectively, 98% and99% homology with reference 890 strain of BVD virus. The recovered Bashkiria/2019, Samara/2020, Kirov/2020 isolates were classified as belonging to subtypes 1i, 1f and1b ofgenotype1, and Belgorod/2021 solate represents genotype 3 of the virus. The findings from the study confirm the presence of all three genotypes of bovine viral diarrhea virus in the Russian Federation and reiterate the need for the development of specific prevention and diagnosis tools for the disease.