Subclinical infection caused by a recombinant vaccine-like strain poses high risks of lumpy skin disease virus transmission.

Lumpy skin disease (LSD) is a transboundary viral infection, affecting cattle with characteristic manifestations involving multiple body systems. A distinctive characteristic of lumpy skin disease is the subclinical disease manifestation wherein animals have viremia and shed the virus through nasal and ocular discharges, while exhibiting no nodules but enlarged lymph nodes that are easily oversighted by inexperienced vets. Further research on the role of subclinically ill animals in the transmission of LSD virus (LSDV) can contribute to the development of more effective tools to control the disease worldwide. Thus, this study aims to determine the potential role of subclinical infection in virus transmission in a non-vector-borne manner. To achieve this, we inoculated animals with the recombinant vaccine-like strain (RVLS) Udmurtiya/2019 to cause clinical and subclinical LSDV infection. After the disease manifestation, we relocated the subclinically ill animals to a new clean facility followed by the introduction of another five animals to determine the role of RVLS-induced subclinical infection in the virus transmission via direct/indirect contact. After the introduction of the naïve animals to the relocated subclinically ill ones in a shared airspace, two introduced animals contracted the virus (clinically and subclinically), showing symptoms of fever, viremia, and seroconversion in one animal, while three other introduced animals remained healthy and PCR-negative until the end of the study. In general, the findings of this study suggest the importance of considering LSDV subclinical infection as a high-risk condition in disease management and outbreak investigations.

The Live Attenuated Vaccine Strain "ARRIAH" Completely Protects Goats from a Virulent Lineage IV Field Strain of Peste Des Petits Ruminants Virus.

Peste des petits ruminants (PPR) is a transboundary viral disease that affects small ruminants, such as goats and sheep, in Africa, the Middle East, and Asia, causing substantial damage to livelihoods and disrupting livestock trade. Although Russia is PPR virus (PPRV)-free, controlling PPRV in neighboring countries is the top national priority. Recent PPR outbreaks in Mongolia and other countries in the Middle East caused by a lineage IV virus represent a risk of transboundary emergence in neighboring countries, including China, Kazakhstan, and Russia. In the present study, we assessed the potency and safety of the ARRIAH live attenuated PPRV vaccine (lineage II) in Zaannen and Nubian goat breeds by challenging them with a virulent lineage IV Mongolia/2021 isolate. For comparison, two commercial vaccines of Nigeria75/1 strain were used. The ARRIAH-vaccinated animals showed an increase in body temperature of 1-1.5 °C above the physiological norm, similar to the animals vaccinated with Nigeria75/1 vaccines. In all vaccinated groups, the average rectal temperature never exceeded 39.4-39.7 °C throughout the infection period, and no clinical signs of the disease were observed, demonstrating vaccine efficacy and safety in the current experimental setting. However, the control group (mock vaccinated) challenged with Mongolia/2021 PPRV exhibited moderate-to-severe clinical signs. Overall, the findings of the present study demonstrate that the ARRIAH vaccine strain has a promising protective phenotype compared with Nigeria75/1 vaccines, suggesting its potential as an effective alternative for curbing and controlling PPR in affected countries. Although the ARRIAH vaccine against PPR is not currently endorsed by the World Organization for Animal Health due to its incomplete safety and potency profile, this study is the first step to provide experimentally validated data on the ARRIAH vaccine.

Metagenomic profiling of viral and microbial communities from the pox lesions of lumpy skin disease virus and sheeppox virus-infected hosts.

Introduction: It has been recognized that capripoxvirus infections have a strong cutaneous tropism with the manifestation of skin lesions in the form of nodules and scabs in the respective hosts, followed by necrosis and sloughing off. Considering that the skin microbiota is a complex community of commensal bacteria, fungi and viruses that are influenced by infections leading to pathological states, there is no evidence on how the skin microbiome is affected during capripoxvirus pathogenesis. Methods: In this study, shotgun metagenomic sequencing was used to investigate the microbiome in pox lesions from hosts infected with lumpy skin disease virus and sheep pox virus. Results: The analysis revealed a high degree of variability in bacterial community structures across affected skin samples, indicating the importance of specific commensal microorganisms colonizing individual hosts. The most common and abundant bacteria found in scab samples were Fusobacterium necrophorum, Streptococcus dysgalactiae, Helcococcus ovis and Trueperella pyogenes, irrespective of host. Bacterial reads belonging to the genera Moraxella, Mannheimia, Corynebacterium, Staphylococcus and Micrococcus were identified. Discussion: This study is the first to investigate capripox virus-associated changes in the skin microbiome using whole-genome metagenomic profiling. The findings will provide a basis for further investigation into capripoxvirus pathogenesis. In addition, this study highlights the challenge of selecting an optimal bioinformatics approach for the analysis of metagenomic data in clinical and veterinary practice. For example, direct classification of reads using a kmer-based algorithm resulted in a significant number of systematic false positives, which may be attributed to the peculiarities of the algorithm and database selection. On the contrary, the process of de novo assembly requires a large number of target reads from the symbiotic microbial community. In this work, the obtained sequencing data were processed by three different approaches, including direct classification of reads based on k-mers, mapping of reads to a marker gene database, and de novo assembly and binning of metagenomic contigs. The advantages and disadvantages of these techniques and their practicality in veterinary settings are discussed in relation to the results obtained.

Genome sequence characterization of the unique recombinant vaccine-like lumpy skin disease virus strain Kurgan/2018.

In 2018, the molecular epidemiology of lumpy skin disease in Russia was characterized by a surge in novel recombinant vaccine-like strains causing outbreaks along the southern border, spreading in an easterly direction. Currently, five distinct novel recombinant vaccine-like lineages have been described, designated as clusters 2.1 to 2.5. Based on the complete genome sequence analysis of the causative lumpy skin disease virus (Kurgan/Russia/2018), obtained from an eponymous outbreak, the genome was shown to be composed of a Neethling vaccine strain virus as the dominant parental strain and KSGPO vaccine virus as its minor parental strain. These features are similar to those of Saratov/Russia/2017 and Tyumen/Russia/2018, representing clusters 2.1 and 2.4, respectively. However, Kurgan/Russia/2018 has 16 statistically significant recombination events unique to this sequence, contributing to the phylogenetic clustering of Kurgan/Russia/2018 in yet another cluster designed cluster 2.6, based on analysis involving the complete genome sequences.

Comparison of Gross Pathology between Classical and Recombinant Lumpy Skin Disease Viruses.

The pathology caused by three different isolates of lumpy skin disease virus, classical field cluster 1.2 strain Dagestan/2015, recombinant vaccine-like cluster 2.1 strain Saratov/2017, and cluster 2.2 strain Udmurtiya/2019, in cattle was compared from experimental infections. The infection of cattle was performed using intravenous administration of 2 mL of 105 TCID50/mL of each specific LSDV. Both classical and recombinant forms of LSDV cause pathological changes in the skin and lymph nodes, as well as the trachea and lungs. Due to circulatory disorders in the affected organs, multiple areas of tissue necrosis were observed, which, with the resurgence of secondary microflora, led to the development of purulent inflammation. Observed pathological changes caused by the recombinant vaccine-like strain Udmurtiya/2019 were characterized by a more pronounced manifestation of the pathoanatomical picture compared to the classical field strains Dagestan/2015 and Saratov/2017. Interestingly, Dagestan/2015 and Udmurtiya/2019 caused damage to the lymph nodes, characterized by serous inflammation and focal purulent lymphadenitis caused by purulent microflora. "Saratov/2017" did not cause pathology in the lymph nodes. All LSDVs were virulent and caused pathology, which was not distinguishable between viruses. This data set will serve as the experimentally validated basis for the comparative examination of novel LSDV strains in gross pathology.

Experimentally controlled study indicates that the naturally occurring recombinant vaccine-like lumpy skin disease strain Udmurtiya/2019, detected during freezing winter in northern latitudes, is transmitted via indirect contact.

Lumpy skin disease (LSD) caused by LSD virus (LSDV), is a member of the poxvirus genus Capripoxvirus. It is classified as a notifiable disease by the World Organization for Animal Health (WOAH) based on its potential for rapid spread and global economic impact. Due to these characteristics, the mode of LSDV transmission has prompted intensive research efforts. Previous experimental studies using the virulent vaccine-derived recombinant LSDV strain Saratov/2017, demonstrated that this strain has the capacity for transmission in a vector-proof environment. This study demonstrated that a second novel recombinant vaccine-derived LSDV strain Udmurtiya/2019, can infect bulls in contact with diseased animals, in the absence of insect vectors. Bulls were housed in an insect proof animal biosafety level 3 facility, where half the animals were inoculated intravenously with the recombinant LSDV (Udmurtiya/2019), whilst the remaining five animals were mock-inoculated but kept in contact with the inoculated group. Both the infected / inoculated group (IN) and uninfected / incontact group (IC), were monitored for 41 days with continuous registration of body temperature, observations for clinical signs and collection of blood samples and nasal swabs for testing of LSDV presence using real-time PCR. Results indicated that cohabitation of animals from both groups was sufficient to transmit the virus from the IN to the IC-group, with the onset of clinical signs including pyrexia (~41°C) and classical LSD nodular skin lesions starting at 10 dpi for the IN group and 16 dpi for the IC-group. Additionally, the presence of LSDV genomes as well as anti-LSDV antibodies were detected in swabs, blood and serum samples from animals belonging to both groups. These results provides additional evidence of LSDV transmission in a controlled environment without direct contact between diseased and healthy animals, yet in the absence of vectors. Based on these observations, the question concerning a hypothetical relation between mutations in the virus genome and its mode of transmission gains more importance and requires additional investigations with direct comparisons between classical and novel recombinant LSDV strains.

Genetic characterization of sheep pox virus strains from outbreaks in Central Russia in 2018-2019.

This study investigates the phylogenomic relatedness between sheep pox viruses (SPPVs) circulating in Central Russia in 2018-2019 with the NISKHI vaccine strain used in the country, based on their complete genome sequences. The sheep pox outbreaks occurred 1 year apart in the adjacent regions of Tula and Moscow. Full genome sequences were generated by sequencing DNA directly obtained from Trizol-extracted scabs, using the DNBSEQ-400 platform (MGI Tech, China). Phylogenetic analysis indicated that the SPPV isolates from Russia clusters with previously published sequences from Srinagar in the Kashmir province of India in 2000 (SPPV-Srinagar strain) as well as SPPV A strain from Kazakhstan in 2000. The aforementioned cluster belonged to a sister clade containing the NISKHI vaccine strain, thus indicating that the recent outbreaks were not genetically linked to the widely used vaccine.

Genetic characterization and epidemiological analysis of the first lumpy skin disease virus outbreak in Mongolia, 2021.

Novel lumpy skin disease virus (LSDV) strains of recombinant origin are on the rise in South East Asia following the first emergence in 2017, and published evidence demonstrates that such genetic lineages currently dominate the circulation. Mongolia reported first LSD outbreaks in 2021 in a north-eastern region sharing borders with Russia and China. For each of 59 reported LSDV outbreaks, the number of susceptible animals ranged from 8 to 8600 with a median of 572, while the number of infected animals ranged from one to 355 with a median of 14. Phylogenetic inferences revealed a close relationship of LSDV Mongolia/2021 with recombinant vaccine-like LSDV strains from Russia, China, Taiwan, Thailand and Vietnam. These findings support the published data that the circulating strain of LSDV belongs to the dominant recombinant lineage recently established in the region.

A Recombinant Vaccine-like Strain of Lumpy Skin Disease Virus Causes Low-Level Infection of Cattle through Virus-Inoculated Feed.

Since 1989, lumpy skin disease of cattle (LSD) has spread out of Africa via the Middle East northwards and eastwards into Russia, the Far East and South-East Asia. It is now threatening to become a worldwide pandemic, with Australia possibly next in its path. One of the research gaps on the disease concerns its main mode of transmission, most likely via flying insect vectors such as biting flies or mosquitoes. Direct or indirect contact transmission is possible, but appears to be an inefficient route, although there is evidence to support the direct contact route for the newly detected recombinant strains first isolated in Russia. In this study, we used experimental bulls and fed them via virus-inoculated feed to evaluate the indirect contact route. To provide deeper insights, we ran two parallel experiments using the same design to discover differences that involved classical field strain Dagestan/2015 LSDV and recombinant vaccine-like Saratov/2017. Following the attempted indirect contact transmission of the virus from the inoculated feed via the alimentary canal, all bulls in the Dagestan/2015 group remained healthy and did not seroconvert by the end of the experiment, whereas for those in the Saratov/2017 recombinant virus group, of the five bulls fed on virus-inoculated feed, three remained clinically healthy, while two displayed evidence of a mild infection. These results provide support for recombinant virus transmission via the alimentary canal. In addition, of particular note, the negative control in-contact bull in this group exhibited a biphasic fever at days 10 and 20, developed lesions from day 13 onwards, and seroconverted by day 31. Two explanations are feasible here: one is the in-contact animal was somehow able to feed on some of the virus-inoculated bread left over from adjacent animals, but in the case here of the individual troughs being used, that was not likely; the other is the virus was transmitted from the virus-fed animals via an airborne route. Across the infected animals, the virus was detectable in blood from days 18 to 29 and in nasal discharge from days 20 to 42. Post-mortem and histological examinations were also indicative of LSDV infection, supporting further evidence for rapid, in F transmission of this virus. This is the first report of recombinant LSDV strain transmitting via the alimentary mode.

Phylogenetic analysis of lumpy skin disease virus isolates in Russia in 2019-2021.

Lumpy skin disease continues to pose a threat to countries in the East and Asia-Pacific regions. Although only occasional LSDV outbreaks have been reported recently in Russia, these have been mainly restricted to the Far East region of the country. An increase in the number of outbreaks in South East Asia has been attributed to recombinant vaccine-like LSDV strains. In this scenario, it is epidemiologically important to perform phylogenetic analysis to track the distribution of LSDV worldwide at the genetic level to understand routes of migration and molecular evolution patterns. In this study, we investigated the RPO30 and GPCR gene regions of LSDV isolates associated with outbreaks in 2019-2021 in Siberia and the Far East region of Russia. The inferred phylogeny confirms the recombinant origin of these sequenced isolates. Based on sequences of these selected loci, the isolates from 2019 differed from isolates detected in Russia in the past and from isolates from Asian countries, while the isolates from 2020 and 2021 exhibited a high degree of similarity to the Asian isolates. These findings indicate that recombinant LSDV strains continue to persist and additionally point to the establishment of a specific lineage of recombinant isolates in the region. Full genome sequencing is still needed to gain more information about how the circulating isolates are related to each other.

An in-depth bioinformatic analysis of the novel recombinant lumpy skin disease virus strains: from unique patterns to established lineage.

BACKGROUND: Since the first description of lumpy skin disease virus (LSDV) in Africa in the 1920's, it has brazenly spread beyond Africa into the Middle East, Europe and most recently Asia. In 2017 the first atypical LSDV recombinant strain was reported in Russia, composed of both a live-attenuated Neethling vaccine strain and Kenyan vaccine strain. An increase in LSDV research enabled a public release of numerous full genome sequences of unique recombinant LSDV strains from Kazakhstan, Russia, China and Vietnam. Prior to the recombinant strain first described in China in 2019, every new recombinant strain was genetically unique and each of these recombinants clustered in a monophyletic lineage. In this work, we provide the complete genome sequences of two novel recombinant strains of LSDV from Russia and attempt to gain more insight into genomic composition of all the recombinant strains currently available. This analysis will provide new insight into the global molecular epidemiology of LSDV. RESULTS: By sequencing and analyzing two novel recombinant strains Khabarovsk/2020 and Tomsk/2020, this study investigates the differences and similarities of all five the available recombinant LSDV lineages from different countries based on the SNPs inherited from the aforementioned parental strains. A total of seven recombinant strains: LSDV/Russia/Saratov/2017, LSDV/Russia/Udmurtya/2019, LSDV/KZ-Kostanay/Kazakhstan/2018, LSDV/Russia/Tyumen/2019, LSDV/GD01/China/2020 Khabarovsk/2020 and Tomsk/2020 were examined. It was observed that strains isolated prior to 2020 were composed of unique combinations of open reading frames, whilst from 2020 onwards all circulating strains in Russia and South-Eastern Asia belonged to a single lineage radiating out in the region. The first representative of this lineage is LSDV/GD01/China/2020. Interestingly, the other four unique recombinant strains as well as the newly established lineage, exhibit consistent patterns of targeted selection pointing to regions constantly selected for during the recombination-driven processes. CONCLUSION: This study highlights the inexplicable emergence of novel recombinant strains to be unique introductions of sibling viruses, with the most recent recombinant lineage establishing as the dominant strain across the south eastern Asian countries as evidenced by full genome sequence data. Overall, these findings indicate that LSDVs are subjected to accelerated evolutionary changes due to recombination in the face of homologous live attenuated vaccines as well as the slow genetic drift commonly observed in capripoxviruses curculatign in the field with hardly any genetic changes over decades.

The changing epidemiology of lumpy skin disease in Russia since the first introduction from 2015 to 2020.

Lumpy skin disease (LSD) is an economically important transboundary disease affecting cattle, causing large economic losses such as decreased production and trade restrictions. LSD has been a historically neglected disease since it previously caused disease limited to the African continent. Currently, the epidemiology of LSD virus is based on how the disease is transmitted in tropical and sub-tropical climates. The understanding of its epidemiology in hemiboreal climates is not well understood and needs urgent attention to expand the current knowledge. In this study, the epidemiological findings on LSD in Russia over a 6-year period are summarized and discussed. A total of 471 outbreaks were identified spanning over a 9000 km range. The outbreaks of LSD occur primarily in small holder farms (backyard) compared to commercial farms between mid-May through mid-November including weather conditions with snow and freezing temperatures that preclude vector activity. Mortality and morbidity varied across the 6 years ranging from 1.19% to 61.8% and 0% to 50%, respectively, with a tendency to decline from 2015 to 2020. The geographic pattern of spread was assessed by means of directionality, indicating a northward movement from 2015 to 2016, with a consequent East turn in 2017 through Siberia to the Far East by 2020. All cases occurred along the border with Kazakhstan. Mathematical modelling showed that the disease tended to form statistically verified annual spatiotemporal clusters in 2016-2018, whereas in 2019 and 2020 such segregation was not evident. The trend of spread was mainly either from south to north or from south to a north-east direction.

Molecular characterization of a novel recombinant lumpy skin disease virus isolated during an outbreak in Tyumen, Russia, in 2019.

Lumpy skin disease virus causes a debilitating pox disease of domesticated cattle and water buffalos. In the last decade, LSDV has spread from Africa into the Middle East, Europe and most recently Asia. As of 2017, atypical outbreaks caused by novel LSDV strains were reported in Russia, followed by China and Vietnam between 2018 and 2020. In this work, we describe another unique recombinant LSDV strain recovered from Tyumen, Russia in 2019. Typing of the virus using currently available qPCR protocols produced inconclusive results and subsequently the complete genome of the isolate was determined. The consensus genome contained statistically significant signals of possible recombination events between parental strains KSGPO-240/Kenya/1958 and the live attenuated vaccine LW/1958. The novel strain carries 25 unique breakpoints different from the known recombinant strains. Additionally, the findings reiterate the importance of complete genome sequencing when analysing outbreak samples caused in particular by mosaic LSDV, in contrast to only performing specified qPCRs.

Overwintering of recombinant lumpy skin disease virus in northern latitudes, Russia.

Lumpy skin disease is an emerging transboundary infection demonstrating a great range expansion worldwide recently. With many knowledge gaps, there is a lack of understanding how lumpy skin disease virus (LSDV), including naturally occurring vaccine-like LSDV, is capable of surviving under different climatic conditions. In this study, we describe a recombinant vaccine-like LSDV from an outbreak in Saratov region of Russia in 2019, where the first recombinant Saratov/2017 was documented. Although the two isolates were two years apart, Saratov/2019 seems to be clonally derived from Saratov/2017 with accrual of mutations characteristic of circulating under selective conditions. The obtained findings demonstrate the persistence of LSDV during winter and successful overwintering in in cold climate, necessitating an objective need for deeper research into LSDV biology.

Estimating evolutionary changes between highly passaged and original parental lumpy skin disease virus strains.

Research into the phylogenetic relationships of lumpy skin disease virus (LSDV) strains was long overlooked, partially due to its original restricted distribution to sub-Saharan Africa. However, recent incursions into northern latitudes, and a rapid spread causing major economic losses worldwide, have intensified additional research on the disease and the causative virus. This study delineates the phylogeny of LSDV in the context of full genome sequences of strains recovered in the field, as well as strains highly passaged in cell culture. We sequenced the oldest known field strain to date (isolate LSDV/Haden/RSA/1954 [South Africa] recovered from an outbreak in 1954), a recent field isolate (LSDV/280-KZN/RSA/2018 [South Africa] sequenced directly from blood during an outbreak in 2018) and strain LSDV/Russia/Dagestan-75 (a high-passaged cell culture strain derived from the field strain, LSDV/Russia/Dagestan/2015 [Russia]). Sequence analysis placed the field strain LSDV/Haden/RSA/1954 in the same cluster (cluster 1.1) with attenuated Neethling-type commercial vaccine viruses, with eight SNP differences, discrediting the previously held hypothesis that cluster 1.1 vaccine strains were derived from cluster 1.2 field viruses via the process of attenuation between them. In contrast, the recent LSDV/280-KZN/RSA/2018 isolate grouped with other recent field isolates in cluster 1.2, providing evidence that cluster 1.1 strains were displaced by cluster 1.2 strains in South Africa. Based on the field isolates between 1954 and 2018, the substitution rate of 7.4 × 10-6 substitutions/site/year was established, with mutations occurring in either synonymous sites or intergenic regions. This is the first evolutionary metric recorded for LSDV. Comparing the genome sequences of high-passage strains of LSDV showed that propagation in vitro without animal host selective pressure generates mainly non-synonymous SNPs in virus-replication genes. These results improve our understanding of LSDV evolution and demonstrate that the population dynamics of circulating isolates is not constant, with LSDV associated with different genetic clusters dominating the landscape during specific periods in time.

Enzymatic Activity and Microbial Diversity of Sod-Podzolic Soil Microbiota Using 16S rRNA Amplicon Sequencing following Antibiotic Exposure.

Antibiotic contamination of the environment negatively affects soil fertility by disrupting natural microbial communities. Currently, the study of the effect of antibacterial drugs on soils typical in Russia, which are of great importance for agriculture, is insufficient. Despite a rapid increase in the number of metagenomic studies, this article is the first publication devoted to the microbial diversity of sod-podzolic soil and its relationship with enzymatic activity. In the present study, we use 16S rRNA metagenomic sequencing to analyze microbiota dynamics and to examine soil enzymatic activities after antibiotic treatment with benzylpenicillin, oxytetracycline, and tylosin. We found that, following treatment, urease activity was reduced regardless of the antibiotic used while nitrification activity showed no statistically significant changes (p > 0.05). Oxytetracycline and tylosin produced no effect on catalase activity but benzylpenicillin caused an increase. Benzylpenicillin and oxytetracycline increased cellulolytic activity whereas tylosin had no significant effect (p > 0.05). Microbiome profiling through 16S rRNA gene sequencing demonstrated antibiotic administration and exhibited no significant impact on bacterial abundance and species diversity (p > 0.05), thus pointing to the resilience of the soil microbial community. Oxytetracycline, benzylpenicillin, and tylosin are likely to negatively affect the enzymatic profiles in sod-podzolic soil but with a negligible influence on the bacterial composition.

A lumpy skin disease virus which underwent a recombination event demonstrates more aggressive growth in primary cells and cattle than the classical field isolate.

Genomic changes by recombination have been recently observed in lumpy skin disease viruses circulating in Russia. The first characterized naturally occurring recombinant lumpy skin disease virus Saratov/2017 occurred through recombination between a live attenuated virus vaccine and the Southern African lumpy skin disease virus. Understanding if recombination can increase or decrease virulence of viruses through changes in different gene regions is required to improve the understanding of capripoxvirus biology. In this study, the in vitro and in vivo growth of the recombinant Saratov/2017 and the classical field isolate Dagestan/2015 was compared. Primary lamb kidney and lamb testis cells as well as the goat ovarian cell line were used to assess virus replication. In the goat ovarian cell line, Saratov/2017 and Dagestan/2015 induced comparable cytopathic activity and virus titres. In contrast, in primary lamb kidney and lamb testis cells, Saratov/2017 grew more aggressively causing more massive rounding up of cells, detachment and agglomeration compared to Dagestan/20152015. Growth curves of Saratov/2017 and Dagestan/2015 were assessed in primary lamb testis cells using different multiplicities of infection (MOI), with Saratov/2017 demonstrating faster replication at the different MOI and time points evaluated post-infection. In cattle, Saratov/2017 demonstrated more pronounced skin reactions when titrated by skin inoculation of serially diluted virus. In both primary cells and cattle, the titre of Saratov/2017 was significantly higher compared to Dagestan/2015 (p ≤ .05). These results demonstrate recombinant Saratov/2017 exhibits more aggressive replication properties.

Performance of the currently available DIVA real-time PCR assays in classical and recombinant lumpy skin disease viruses.

The use of live homologous vaccines to protect against lumpy skin disease virus (LSDV) infection requires the use of molecular tools to differentiate between infected and vaccinated animals (DIVA). In this study, the commercial real-time PCR assays; ID Gene™ LSD DIVA Triplex kit and Bio-T kit® LSD - DIVA, as well as published assays targeting the GPCR gene (Journal of Virological Methods, 249, 48-57) and ORF008 and ORF126 (Sel'skokhozyaistvennaya Biologiya, 54, 347-358) were evaluated. These assays correctly identified classical field isolates (European lineage) and vaccine (Neethling vaccine). In contrast, when tested using vaccine-like recombinant viruses, the commercial and published assays were not able to correctly identify recombinant isolates. At the same time, the recombinant viruses were detected as either field and/or vaccine, or not detected at all depending on the assay. The different gene sequences present in recombinant viruses cause these DIVA assays to incorrectly assign recombinant viruses as either a field or vaccine virus. This observation has implications for using these assays and for identification of LSDV vaccine.

Full-length genome characterization of a novel recombinant vaccine-like lumpy skin disease virus strain detected during the climatic winter in Russia, 2019.

An uncharacteristic outbreak of lumpy skin disease was reported in the Republic of Udmurtiya, Russia, during the climatic winter of March 2019. The causative lumpy skin disease virus (LSDV_Udmurtiya_Russia_2019) was shown to be a recombinant composed of a live attenuated Neethling-type vaccine strain as the dominant parental strain and a Kenyan KSGP/NI-2490-like virus as its minor parental strain, with 24 statistically significant recombination events that are not identical to those in LSDV Saratov/2017, in which 27 events were identified.