Capripoxviruses: an emerging worldwide threat to sheep, goats and cattle

Structural and sequence analysis of the RPO30 gene of sheeppox and goatpox viruses from India

Sheeppox and goatpox are transboundary viral diseases of sheep and goats that cause significant economic losses to small and marginal farmers worldwide, including India. Members of the genus Capripoxvirus (CaPV), namely Sheeppox virus (SPPV), Goatpox virus (GTPV), and Lumpy skin disease virus (LSDV), are antigenically similar, and species differentiation can only be accomplished using molecular approaches. The present study aimed to understand the molecular epidemiology and host specificity of SPPV and GTPV circulating in India through sequencing and structural analysis of the RNA polymerase subunit-30 kDa (RPO30) gene. A total of 29 field isolates from sheep (n = 19) and goats (n = 10) belonging to different geographical regions of India during the period: Year 2015 to 2023, were analyzed based on the sequence and structure of the full-length RPO30 gene/protein. Phylogenetically, all the CaPV isolates were separated into three major clusters: SPPV, GTPV, and LSDV. Multiple sequence alignment revealed a highly conserved RPO30 gene, with a stretch of 21 nucleotide deletion in all SPPV isolates. Additionally, the RPO30 gene of the Indian SPPV and GTPV isolates possessed several species-specific conserved signature residues/motifs that could act as genotyping markers. Secondary structure analysis of the RPO30 protein showed four α-helices, two loops, and three turns, similar to that of the E4L protein of vaccinia virus (VACV). All the isolates in the present study exhibited host preferences across different states of India. Therefore, in order to protect vulnerable small ruminants from poxviral infections, it is recommended to take into consideration a homologous vaccination strategy.

Platform establishment of the Cre-loxP recombination system for genetic manipulation of the Lumpy skin disease virus

Lumpy skin disease virus (LSDV) is a rapidly emerging pathogen in Asia, including China. Genetic manipulation of the LSDV is essential for the elucidation of the pathogenic mechanism and biological function of the LSDV-encoded protein. In this study, we established a platform for the Cre-loxP recombination system under a modified early-late H5 promoter of the VACV for quick construction of the recombinant LSDV virus. The recombinant virus, LSDV-EGFP-ΔTK, was purified and obtained using serial limited dilution and picking the single cells methods. Using the lentiviral package system, a Cre recombinase enzyme stable expression MDBK cell line was established to supply the Cre recombinase for the reporter gene excision. A genetically stable, safe TK gene-deleted LSDV (LSDV-ΔTK) was constructed using homologous recombination and the Cre-loxP system. It was purified using limited dilution in the MDBK-Cre cell line. Establishing the Cre-loxP recombination system will enable sequential deletion of the interested genes from the LSDV genome and genetic manipulation of the LSDV genome, providing technical support and a platform for developing the attenuated LSDV vaccine.

Identification of the murine osteoblastic cell MC3T3-E1 as a permissive cell line in response to lumpy skin disease virus

Lumpy skin disease virus (LSDV) is a rapidly emerging pathogen in China. Screening suitable cells for LSDV replication is vital for future research on pathogenic mechanisms and vaccine development. Previous comparative studies have identified that the rodent-derived BHK21 is a highly susceptible cell model to LSDV infection. Using western blot, indirect immune-fluorescence assay, flow cytometry, and transmission electron microscopy methods, this study is the first to identify the murine osteoblastic cell line MC3T3-E1 as a novel permissive cell model for LSDV infection. The establishment of MC3T3-E1 as a suitable infectious cell model enhances our understanding of the species range and cell types of the permissive cells and nonpermissive that support LSDV replication. It is helpful to accelerate future research on the pathogenesis, clinical application, and vaccine development of LSDV.

Development of membrane protein-based vaccine against lumpy skin disease virus (LSDV) using immunoinformatic tools

INTRODUCTION

Lumpy skin disease, an economically significant bovine illness, is now found in previously unheard-of geographic regions. Vaccination is one of the most important ways to stop its further spread.

AIM

Therefore, in this study, we applied advanced immunoinformatics approaches to design and develop an effective lumpy skin disease virus (LSDV) vaccine.

METHODS

The membrane glycoprotein was selected for prediction of the different B- and T-cell epitopes by using the immune epitope database. The selected B- and T-cell epitopes were combined with the appropriate linkers and adjuvant resulted in a vaccine chimera construct. Bioinformatics tools were used to predict, refine and validate the 2D, 3D structures and for molecular docking with toll-like receptor 4 using different servers. The constructed vaccine candidate was further processed on the basis of antigenicity, allergenicity, solubility, different physiochemical properties and molecular docking scores.

RESULTS

The in silico immune simulation induced significant response for immune cells. In silico cloning and codon optimization were performed to express the vaccine candidate in Escherichia coli. This study highlights a good signal for the design of a peptide-based LSDV vaccine.

CONCLUSION

Thus, the present findings may indicate that the engineered multi-epitope vaccine is structurally stable and can induce a strong immune response, which should help in developing an effective vaccine towards controlling LSDV infection.

An insight into emergence of lumpy skin disease virus: a threat to Indian cattle

Lumpy skin disease (LSD) is a highly infectious and economically devastating viral disease of cattle. It is caused by Lumpy Skin Disease Virus (LSDV) belonging to the genus Capripoxvirus and family Poxviridae. The origin of lumpy skin disease has been traced to Zambia, (an African nation) in Southern part during the year 1929. The first reported case of LSD besides Africa was from Israel, a Middle Eastern nation, thus proving inter-continental spread. Subsequently, the disease entered Middle East, Eastern Europe and Asia with numerous outbreaks in the recent years. LSD has emerged as a significant concern in the Indian sub-continent, due to outbreaks reported in countries such as Bangladesh, India, China in 2019. In the following years, other South and East Asian countries like Taipei, Nepal, Sri Lanka, Myanmar, Bhutan, Vietnam, Hong Kong, Thailand, Malaysia, Laos, Cambodia, Pakistan, Indonesia and Singapore also faced severe outbreaks. At present, LSD is considered to be an emerging disease in the Indian sub-continent due to the recent status of disease. Considering the global scenario, LSDV is changing its transmission dynamics as evidenced by a shift in its epidemiology. As a result of high morbidity and mortality rate among cattle, the current outbreaks have been a major cause of socio-economic catastrophe. This contagious viral disease has eminent repercussions as the estimated monetary damage incurred is quite high. Despite having networked surveillance and comprehensive databases, the recurring outbreaks have raised major concern among researchers. Therefore, this review offers brief insights into the emergence of LSDV by amalgamating the newest literature related to its biology, transmission, clinico-pathology, epidemiology, prevention strategies, and economic consequences. Additionally, we have also provided the epidemiological insights of the recent outbreaks with detailed state wise studies.

Duration of Immunity in Cattle to Lumpy Skin Disease Utilizing a Sheep Pox Vaccine

The transmission of lumpy skin disease (LSD) occurs through ticks, mosquitoes, and flies. The most effective way to combat LSD is to conduct large-scale vaccination, covering the entire cattle population with safe and effective vaccines, while introducing restrictions on the movement of livestock. The first and only LSD cases that occurred in Armenia happened in 2015,and they were controlled with the use of a once yearly heterologous sheep pox vaccine for cattle in high-risk areas. We have previously reported on the safety and immunogenicity of this vaccine in cattle, but information on the duration of immunity is lacking. Our aim was to determine the duration of immunity to the LSD virus (LSDV) in cattle when utilizing a heterologous sheep pox vaccine. We have evaluated antibodies in cattle blood prior to and post-vaccination (1, 6, and 11 months). We have utilized an enzyme-linked immunosorbent assay to follow the development and waning of LSDV antibodies in vaccinated cattle in two age groups: 1) young unvaccinated cattle ≤12 months of age and 2) adult cattle that had previously been vaccinated. Our results were consistent with our previous study in Armenia, showing a high level of population immunity, 80.0-83.3%, in both age groups at 1 month, with a significant (p = 0.001) drop for young cattle at 6 months. Previously vaccinated adult cattle showed a longer duration of immunity at 11 months for this heterologous sheep pox vaccine. Based on these data, we advise that young cattle receive an additional booster vaccination 4-6 months after their first vaccination, and then yearly vaccinations in high-risk areas.

Spatio-temporal ditribution and transmission dynamics of sheep pox and goat pox diseases in South Wollo zone north East Ethiopia

Sheep pox (SP) and goat pox diseases (GP) are highly transmittable, malignant systemic and economically significant caused by the genus Capripoxvirus. using The spatio-temporal distribution of SP and GP outbreaks in South Wollo zone from September 2013 to December 2019 was determined retrospectively using SP and GP outbreaks report Kombolcha regional laboratory. A follow up study was also conducted from December 2019 to March 2021 to estimate the transmission parameter of SP and GP outbreaks in South Wollo zone of Kutaber district, Amhara region. Tissue samples from outbreaks in Kundi and Haroye kebele of Kutaber district were taken to confirm the outbreak by conventional polymerase chain reaction (PCR). The transmission parameters were estimated using Generalized linear model (GLM) based on stochastic Susceptible Infected and Recovered (SIR) model. In South Wollo zone, 249 SGP outbreaks were reported from 2013 to 2019. The incidence differed between months, with a highest peak in October and November and a lowest peak in February. The basic reproduction ratios (R0) of the SGP disease outbreaks were 1.84 and 3 for Haroye and Kundi kebele outbreaks, respectively. The disease is distributed throughout the zone and the investigated active outbreaks had moderate transmission between animals. Hence, it needs a great effort which focuses on the application of control measures that reduce the transmission of the disease.

Molecular characterization of recombinant LSDV isolates from 2022 outbreak in Indonesia through phylogenetic networks and whole-genome SNP-based analysis

Lumpy skin disease (LSD) is a transboundary viral disease of cattle and water buffaloes caused by the LSD virus, leading to high morbidity, low mortality, and a significant economic impact. Initially endemic to Africa only, LSD has spread to the Middle East, Europe, and Asia in the past decade. The most effective control strategy for LSD is the vaccination of cattle with live-attenuated LSDV vaccines. Consequently, the emergence of two groups of LSDV strains in Asian countries, one closely related to the ancient Kenyan LSDV isolates and the second made of recombinant viruses with a backbone of Neethling-vaccine and field isolates, emphasized the need for constant molecular surveillance. This current study investigated the first outbreak of LSD in Indonesia in 2022. Molecular characterization of the isolate circulating in the country based on selected LSDV-marker genes: RPO30, GPCR, EEV glycoprotein gene, and B22R, as well as whole genome analysis using several analytical tools, indicated the Indonesia LSDV isolate as a recombinant of LSDV_Neethling_vaccine_LW_1959 and LSDV_NI-2490. The analysis clustered the Indonesia_LSDV with the previously reported LSDV recombinants circulating in East and Southeast Asia, but different from the recombinant viruses in Russia and the field isolates in South-Asian countries. Additionally, this study has demonstrated alternative accurate ways of LSDV whole genome analysis and clustering of isolates, including the recombinants, instead of whole-genome phylogenetic tree analysis. These data will strengthen our understanding of the pathogens' origin, the extent of their spread, and determination of suitable control measures required.

Unravelling the genomic origins of lumpy skin disease virus in recent outbreaks

Lumpy skin disease virus (LSDV) belongs to the genus Capripoxvirus and family Poxviridae. LSDV was endemic in most of Africa, the Middle East and Turkey, but since 2015, several outbreaks have been reported in other countries. In this study, we used whole genome sequencing approach to investigate the origin of the outbreak and understand the genomic landscape of the virus. Our study showed that the LSDV strain of 2022 outbreak exhibited many genetic variations compared to the Reference Neethling strain sequence and the previous field strains. A total of 1819 variations were found in 22 genome sequences, which includes 399 extragenic mutations, 153 insertion frameshift mutations, 234 deletion frameshift mutations, 271 Single nucleotide polymorphisms (SNPs) and 762 silent SNPs. Thirty-eight genes have more than 2 variations per gene, and these genes belong to viral-core proteins, viral binding proteins, replication, and RNA polymerase proteins. We highlight the importance of several SNPs in various genes, which may play an essential role in the pathogenesis of LSDV. Phylogenetic analysis performed on all whole genome sequences of LSDV showed two types of variants in India. One group of the variant with fewer mutations was found to lie closer to the LSDV 2019 strain from Ranchi while the other group clustered with previous Russian outbreaks from 2015. Our study highlights the importance of genomic characterization of viral outbreaks to not only monitor the frequency of mutations but also address its role in pathogenesis of LSDV as the outbreak continues.

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.

Cracking the Code of Lumpy Skin Disease: Identifying Causes, Symptoms and Treatment Options for Livestock Farmers

The novel bovine viral infection known as lumpy skin disease is common in most African and Middle Eastern countries, with a significant likelihood of disease transfer to Asia and Europe. Recent rapid disease spread in formerly disease-free zones highlights the need of understanding disease limits and distribution mechanisms. Capripox virus, the causal agent, may also cause sheeppox and Goatpox. Even though the virus is expelled through several bodily fluids and excretions, the most common causes of infection include sperm and skin sores. Thus, vulnerable hosts are mostly infected mechanically by hematophagous arthropods such as biting flies, mosquitoes, and ticks. As a result, milk production lowers, abortions, permanent or temporary sterility, hide damage, and mortality occur, contributing to a massive financial loss for countries that raise cattle. These illnesses are economically significant because they affect international trade. The spread of Capripox viruses appears to be spreading because to a lack of effectual vaccinations and poverty in rural areas. Lumpy skin disease has reached historic levels; as a consequence, vaccination remains the only viable option to keep the illness from spreading in endemic as well as newly impacted areas. This study is intended to offer a full update on existing knowledge of the disease's pathological characteristics, mechanisms of spread, transmission, control measures, and available vaccinations.

Production of recombinant lumpy skin disease virus A27L and L1R proteins for application in diagnostics and vaccine development

Vaccination using live attenuated vaccines (LAVs) is considered the most effective method for control of lumpy skin disease (LSD). However, this method is limited by safety concerns, with reports of adverse reactions following vaccination. This study evaluates A27L and L1R which are essential proteins for virus attachment and membrane fusion as recombinant sub-unit vaccines against LSD. These proteins were recombinantly expressed in Escherichia coli and purified using affinity chromatography. Purified proteins were formulated individually (A27L or L1R) and in combination (A27L and L1R) with 10% (w/w) Montanide™ Gel 01 PR adjuvant at a final antigen dose of 20 µg per protein. The safety and immunogenicity of these formulations were evaluated in rabbits in a 42-day clinical trial. Animals were vaccinated on day 0 and boost injection administered 21 days later. No reduced morbidity, increased temperature and any other clinical signs were recorded in vaccinated animals for all three vaccine formulations. The highest neutralizing antibody response was detected on day 42 post-primary vaccination for all formulations when using serum neutralising assay. The neutralisation data correlates with antibody titres quantified using a whole cell ELISA. Evaluating the combination of A27L and L1R as potential diagnostic reagents showed highest sensitivity for detection of antibodies against LSD when compared to individual proteins. This study reports the immunogenicity of recombinant A27L and L1R combination for successful application in LSD vaccine development. Furthermore, these proteins demonstrated the potential use in LSD diagnostics.

Lumpy skin disease: history, current understanding and research gaps in the context of recent geographic expansion

Lumpy skin disease is recognized as a transboundary and emerging disease of cattle, buffaloes and other wild ruminants. Being initially restricted to Africa, and since 1989 the Middle East, the unprecedented recent spread across Eurasia demonstrates how underestimated and neglected this disease is. The initial identification of the causative agent of LSD as a poxvirus called LSD virus, was well as findings on LSDV transmission and epidemiology were pioneered at Onderstepoort, South Africa, from as early as the 1940s by researchers such as Weiss, Haig and Alexander. As more data emerges from an ever-increasing number of epidemiological studies, previously emphasized research gaps are being revisited and discussed. The currently available knowledge is in agreement with the previously described South African research experience that LSDV transmission can occur by multiple routes, including indirect contact, shared water sources and arthropods. The virus population is prone to molecular evolution, generating novel phylogenetically distinct variants resulting from a diverse range of selective pressures, including recombination between field and homologous vaccine strains in cell culture that produce virulent recombinants which pose diagnostic challenges. Host restriction is not limited to livestock, with certain wild ruminants being susceptible, with unknown consequences for the epidemiology of the disease.

Estimating the Transmission Kernel for Lumpy Skin Disease Virus from Data on Outbreaks in Thailand in 2021

Nationwide outbreaks of lumpy skin disease (LSD) were observed in Thailand in 2021. A better understanding of its disease transmission is crucial. This study utilized a kernel-based approach to characterize the transmission of LSD between cattle herds. Outbreak data from the Khon Kaen and Lamphun provinces in Thailand were used to estimate transmission kernels for each province. The results showed that the majority of herd-to-herd transmission occurs over short distances. For Khon Kaen, the median transmission distance from the donor herd was estimated to be between 0.3 and 0.8 km, while for Lamphun, it ranged from 0.2 to 0.6 km. The results imply the critical role that insects may play as vectors in the transmission of LSD within the two study areas. This is the first study to estimate transmission kernels from data on LSD outbreaks in Thailand. The findings from this study offer valuable insights into the spatial transmission of this disease, which will be useful in developing prevention and control strategies.

A Real-Time Recombinase Polymerase Amplification Assay for Specific Detection of Lumpy Skin Disease Virus

Lumpy skin disease virus (LSDV) infection, accompanied by loss of hide quality, poor reproductive efficiency, consistent degenerative emaciation, and milk yield reduction of animals, causes severe economic implications in endemic zones. The heterologous attenuated goat pox (GTPV) vaccine (AV41 strain) was used in China to prevent LSDV infection. Only a few LSDV detection methods that distinguish LSDV from GTPV vaccine strains have been reported before. For simple, rapid, and specific detection of LSDV, the real-time recombinase polymerase amplification (RPA) method was established with the specific primers and probes designed according to the conserved regions of ORF132 gene sequences. The assay could be finished within 20 min at a constant temperature (39 °C). This method had a limit of detection (LOD) of 15 copies/μL for LSDV and no cross-reaction with the nucleic acids of goat pox virus, infectious bovine rhinotracheitis virus, Pasteurella multocida, and bovine healthy tissue. Furthermore, 43 clinical samples were detected by this method and the real-time PCR recommended by the World Organisation for Animal Health (WOAH), with a kappa value, was 0.94. These results demonstrated that the real-time RPA method for detecting LSDV developed in this study was characterized by high sensitivity and specificity, which has wide application value in the clinical diagnosis and detection of LSDV in China.

Development of a Real-Time qPCR Method for the Clinical Sample Detection of Capripox Virus

Capripox viruses (CaPVs), including sheep pox virus (SPV), goat pox virus (GPV), and lumpy skin disease virus (LSDV), are the cause of sheep pox (SPP), goat pox (GTP), and lumpy skin disease (LSD) in cattle. These diseases are of great economic significance to farmers, as they are endemic on farms and are a major constraint to international trade in livestock and their products. Capripoxvirus (CaPV) infections produce similar symptoms in sheep and goats, and the three viruses cannot be distinguished serologically. In this study, we developed a real-time quantitative polymerase chain reaction (qPCR) method for identifying CaPV in goats, sheep, and cattle. Clinical samples were tested and verified. The developed assay was highly specific for target viruses, including GPVSPV and LSDV, which had no cross-reaction with other viruses causing similar clinical symptoms. An artificially synthesized positive control plasmid using the CaPV 32 gene inserted into the vector pMD19-T was used as a template, and the correlation coefficient of the linear regression curve (R2) was 0.9916, the estimated amplification efficiency (E) was 96.06%, and the sensitivity (limit of detection, LOD) was 3.80 copies per reaction. Using the clinical samples as a template, the limit of detection (LOD) was 4.91 × 10-5 ng per reaction (1.60 × 10-5-2.13 × 10-3 ng, 95% confidence interval (CI)), which means that this method was one of the most sensitive detection assays for CaPVs. A total of 85 clinical samples from CaPV-infected animals (goats, sheep, and cattle) and 50 clinical samples from healthy animals were used to test and compare the diagnostic results using the Synergy Brands (SYBR) Green-based PCR method recommended by the World Organization of Animal Health (WOAH). Both diagnostic sensitivity (DSe) (95.8-100%, 95% CI) and diagnostic specificity (DSp) (92.9-100%, 95% CI) results of the real-time quantitative PCR (qPCR) and SYBR Green PCR were 100%, and the kappa value (κ) was 1.0 (1-1, 95% CI). In summary, the assay established based on TaqMan probes was advantageous in high specificity, sensitivity, and general applicability and could be a competitive candidate tool for the diagnosis of CaPV in clinically suspected animals.

Development of the isothermal recombinase polymerase amplification assays for rapid detection of the genus Capripoxvirus

Sheeppox virus (SPPV), goatpox virus (GTPV) and lumpy skin disease virus (LSDV) belong to the genus Capripoxvirus (CaPV), and are important pathogens of sheep, goat and cattle, respectively. Rapid and reliable detection of CaPV is critical to prevent its spread and promote its eradication. This study aimed to develop the recombinase polymerase amplification (RPA) assays combined with real-time fluorescence (real-time RPA) and naked-eye visible lateral flow strip (LFS RPA) for rapid detection of CaPV. Both developed RPA assays worked well at 39 °C within 20 min. They were highly specific for the detection of GTPV, SPPV and LSDV, while no cross-reactivity was observed for other non-targeted pathogens and genomic DNA of goat, sheep and cattle. The limit of detection for real-time RPA and LFS RPA were 1.0 × 102 and 1.0 × 101 copies per reaction, respectively. In the artificially contaminated samples with GTPV, the detection results of RPA assays were consistent with those of real-time PCR. For 15 clinical samples, LSDV was detected by real-time RPA, LFS RPA and real-time PCR in 13, 15 and 15 samples, respectively. The developed RPA assays were specific, sensitive, and user-friendly for the rapid detection of CaPV, and could be a better alternative method applied in low-resources settings.

Risk factors, logistic model, and vulnerability mapping of lumpy skin disease in livestock at the farm level in Indragiri Hulu District, Riau Province, Indonesia, in 2022

Background and Aim

Lumpy skin disease (LSD) is an emerging epidemic in livestock in Indonesia. It was first reported in the Indragiri Hulu Regency of Riau Province, which has more cases than the surrounding regencies. This study aimed to identify the risk factors and generate a logistic regression model and vulnerability map of LSD in the Indragiri Hulu Regency.

Materials and Methods

We used a structured questionnaire to interview the case and control farm owners to evaluate the risk factors. We evaluated 244 samples, consisting of 122 case and control farm samples each. At the cattle farm level, the risk factor data related to LSD were analyzed using descriptive statistics, bivariate analysis with Chi-square, and odds ratio, while the logistic model was derived using multivariate logistic regression analysis. Using variables, such as the number of cases and risk factor variables included in the model logistic, and the temperature, humidity, and rainfall data from the Meteorology, Climatology, and Geophysical Agency, we analyzed the vulnerability map of LSD in the regency using scoring, weighting, and overlay methods.

Results

Ten significant risk factors were associated with LSD occurrence. The LSD model obtained from the logistic regression analysis was LSD (Y) = -3.92095 + 1.13107 (number of cattle >3) + 1.50070 (grazing cattle together with other farmers' cattle) + 1.03500 (poor management of farm waste/dirt) + 2.49242 (presence of livestock collectors/traders near the farm location) + 1.40543 (introduction of new livestock) + 2.15196 (lack of vector control measures on the farm). The LSD vulnerability map indicated that the villages with high vulnerability levels were Rantau Bakung, Kuantan Babu, and Sungai Lala in the Rengat Barat, Rengat, and Sungai Lala subdistricts, respectively.

Conclusion

We found 10 significant risk factors associated with LSD occurrence. The LSD model included the number of cattle (>3), cograzing with other farmers' cattle, poor management of farm waste/dirt, the presence of livestock collectors/traders near the farm, introduction of new livestock, and lack of vector control measures on the farm. The LSD vulnerability map indicated that villages with high vulnerability levels included Rantau Bakung in the Rengat Barat subdistrict, Kuantan Babu in the Rengat subdistrict, and Sungai Lala in the Sungai Lala subdistrict.

Development and application of a real-time polymerase chain reaction assay to detect lumpy skin disease virus belonging to the Kenyan sheep and goat pox group

Lumpy skin disease (LSD) outbreaks in Southeast and South Asia are attributed to different lineages of LSD virus (LSDV). Variants belonging to the novel recombinant cluster 2.5 circulate in China and Thailand, while a Kenyan sheep and goat pox (KSGP) strain from cluster 1.1 circulates in India, Pakistan, and Bangladesh. The clusters representing these circulating strains are vastly different. However, if their distribution encroaches into each other's ranges, it will be impossible to differentiate between them due to the lack of suitable molecular tools. Thus, fit-for-purpose molecular tools are in demand to effectively and timeously diagnose and investigate the epidemiology of LSDVs in a region. These could significantly contribute to the phylogenetic delineation of LSDVs and the development of preventive measures against transboundary spillovers. This work aimed to develop a real-time polymerase chain reaction assay targeting open reading frame LW032, capable of specifically detecting KSGP-related isolates and recombinant LSDV strains containing the KSGP backbone. The analytical specificity was proven against the widest possible panel of recombinant vaccine-like LSDV strains known to date. The amplification efficiency was 91.08%, and the assay repeatability had a cycle threshold variation of 0.56-1.1 over five repetitions across three runs. This KSGP-specific assay is reliable and fast and is recommended for use in LSDV epidemiological studies where the accurate detection of KSGP genetic signatures is a priority, particularly in regions where KSGP-like and other lineages are circulating.

A quantitative risk assessment for the incursion of lumpy skin disease virus into Australia via long-distance windborne dispersal of arthropod vectors

Lumpy skin disease (LSD) is an infectious disease of cattle and water buffalo caused by lumpy skin disease virus (LSDV). It is primarily transmitted mechanically by biting insects. LSDV has spread from Africa to the Middle-East, the Balkans, Caucasus, Russia, Kazakhstan, China, Asia and India, suggesting that a wide variety of arthropod vectors are capable of mechanical transmission. In 2022, LSD was detected in Indonesia, heightening awareness for Australia's livestock industries. To better understand the risk of LSDV incursion to Australia we undertook a quantitative risk assessment (QRA) looking at windborne dispersal of arthropod vectors, assuming a hypothetical situation where LSD is endemic in south-east Asia and Papua New Guinea. We estimated the risk of LSDV incursion to be low, with a median incursion rate of one incursion every 403 years, based on a model where several infectious insects (i.e. a 'small batch' of 3-5) must bite a single bovine to transmit infection. The incursion risk increases substantially to one incursion every 7-8 years if a bite from a single insect is sufficient for transmission. The risk becomes negligible (one incursion every 20,706 years) if bites from many insects (i.e. a 'large batch' of 30-50 insects) are necessary. Critically, several of our parameter estimates were highly uncertain during sensitivity analyses. Thus, a key outcome of this QRA was to better prioritise surveillance activities and to understand the key research gaps associated with LSDV in the Australasian context. The current literature shows that multiple vectors are required for successful bovine-to-vector transmission of LSDV, suggesting that our estimate of one outbreak every 403 years more accurately represents the risk to Australia; however, the role of single insects in transmission has not yet been evaluated. Similarly, attempts to transmit LSDV between bovines by Culicoides have not been successful, although midges were the highest risk vector category in our model due to the high vector-to-host ratio for midges compared to other vector categories. Our findings provide further insight into the risk of LSD to Australian cattle industries and identify the Tiwi Islands and areas east of Darwin as priority regions for LSDV surveillance, especially between December and March.

Global Burden of Lumpy Skin Disease, Outbreaks, and Future Challenges

Lumpy skin disease (LSD), a current global concern, causes economic devastation in livestock industries, with cattle and water buffalo reported to have higher morbidity and lower mortality rates. LSD is caused by lumpy skin disease virus (LSDV), a member of the Poxviridae family. It is an enzootic, rapidly explorative and sometimes fatal infection, characterized by multiple raised nodules on the skin of infected animals. It was first reported in Zambia in 1929 and is considered endemic in Africa south of the Sahara desert. It has gradually spread beyond Africa into the Middle East, with periodic occurrences in Asian and East European countries. Recently, it has been spreading in most Asian countries including far East Asia and threatens incursion to LSD-free countries. Rapid and accurate diagnostic capabilities, virus identification, vaccine development, vector control, regional and international collaborations and effective biosecurity policies are important for the control, prevention, and eradication of LSD infections. This review critically evaluates the global burden of LSD, the chronological historical outbreaks of LSD, and future directions for collaborative global actions.

Poxvirus sensitivity of a novel diploid sheep embryonic heart cell line

Lumpy skin disease virus (LSDV), camelpox virus (CPV), and orf virus (ORFV) are members of the family Poxviridae. These viruses are usually isolated or produced in embryonated eggs or primary cells because continuous cell lines are less sensitive to infection. Disadvantages of the use of eggs or primary cells include limited availability, potential endogenous contaminants, and a limited ability to perform multiple passages. In this study, we developed a diploid cell culture from sheep embryonic hearts (EHs) and demonstrated its high proliferative and long-term storage capacities. In addition, we demonstrated its sensitivity to representatives of three genera of the family Poxviridae: Capripoxvirus (LSDV), Orthopoxvirus (CPV), and Parapoxvirus (ORFV). The cell culture had a doubling time of 24 h and reached 40 passages with satisfactory yield. This is comparable to that observed in primary lamb testis (LT) cells at passage 5 (P5). After infection, each poxvirus titer was 7.0-7.6 log TCID50/mL for up to five passages and approximately 6.8, 6.4, and 5.6 for the three viruses at P6-P25, P30, and P40, respectively. The sensitivity of sheep EH cells to poxvirus infection did not decrease after long-term storage in liquid nitrogen and was higher than that of primary LT cells, which are used for capripoxvirus and parapoxvirus detection and growth, and Vero cells, which are used for orthopoxvirus detection and growth. Thus, EH diploid cells are useful for poxvirus isolation and production without embryonated eggs or primary cells.

Assessment of Humoral Immune Response in Pre- and Post-Vaccinated Cattle Against Lumpy Skin Disease

Introduction

Lumpy skin disease (LSD) is viral disease affecting cattle production and productivity in Ethiopia. As a prevention method, vaccinations have been used for a long period with a questionable output due to the existence of LSD outbreaks in vaccinated herds in different parts of Ethiopia.

Methods

A longitudinal study was performed from October 2019 to April 2020 with the objective of assessing the humoral immune response of cattle with a serum neutralization test (SNT) from different management systems in central Ethiopia. In this study, theserum was collected from 113 cattle (extensive (60/113) and intensive (53/113) management systems) before and after vaccination.

Results and Discussion

From collected sera, a limited number of cattle had seroconversion before vaccination (7.08%). On the other hand, it is obvious the seroconversion rises post vaccination. Accordingly, seroconversion starts to increase after a week (8.85% at 7 dpv) post-vaccination which proceeds to significantly increase at 30 days post vaccination (dpv) (41.65% (25/60)). Furthermore, the risk factor study before and after vaccination showed intensively managed cattle with significantly higher levels of antibody titer at 7 dpv (OR = 1.17; 95% CI = 0.22, 6.2; p = 0.016) and 30 dpv (OR = 3.67; 95% CI = 1.1, 12.29; p = 0.035) compared with that of extensively managed cattle. The other animal-related risk factor that showed a significant difference was breeds and a specific age group ([4½, 7] years) at 15 dpv (OR = 6.69; 95% CI = 2.02, 22.08; p = 0.002) and 30 dpv (OR = 4.24; 95% CI = 1.22, 14.71; p = 0.023); respectively.

Conclusion

This study showed an overall lower antibody detection across the study, posing a question on the current LSD-vaccine efficacy. Therefore, a circulating strain of LSDV should be cross-checked with the vaccine strain and adaptations should be made from it.

Diagnosis of Ruminant Viral Diseases with Loop-Mediated Isothermal Amplification

Infectious diseases in livestock industry are major problems for animal health, food safety, and the economy. Zoonotic diseases from farm animals are significant threat to human population as well. These are notifiable diseases listed by the World Organization for Animal Health (OIE). Rapid diagnostic methods can help keep infectious diseases under control in herds. Loop-mediated isothermal amplification (LAMP) is a simple and rapid nucleic acid amplification method that is studied widely for detection of many infectious diseases in the field. LAMP allows biosensing of target DNA or RNA under isothermal conditions with high specificity in a short period of time. An untrained user can analyze results based on color change or turbidity. Here we review LAMP assays to diagnose OIE notifiable ruminant viral diseases in literature highlighting properties of LAMP method considering what is expected from an efficient, field usable diagnostic test.

Phylogenetic and pathogenic characterization of lumpy skin disease virus circulating in China

The genomic characterization of emerging pathogens is critical for unraveling their origin and tracking their dissemination. Lumpy skin disease virus (LSDV) is a rapidly emerging pathogen in Asia including China. Although the first Lumpy skin disease (LSD) outbreak was reported in 2019, the origin, transmission, and evolutionary trajectory of LSDV in China have remained obscure. The viral genome of a circulating LSDV strain in China, abbreviated LSDV/FJ/CHA/2021, was sequenced using the next-generation sequencing technique. The morphology and cytoplasmic viral factory of these LSDV isolates were observed using transmission electron microscopy. Subsequently, the genomic characterization of this LSDV isolate was systematically analyzed for the first time using the bioinformatics software. The current study revealed that several mutations in the genome of LSDV isolates circulating in China were identified using single nucleotide polymorphisms (SNPs) analysis, an instrument to evaluate for continuous adaptive evaluation of a virus. Furthermore, phylogenomic analysis was used to identify the lineage using the whole genome sequences of 44 LSDV isolates. The result revealed that the isolates from China were closely similar to that of the LSDV isolates from Vietnam, which are divided into a monophyletic lineage sub-group I. The SNPs and Simplot analysis indicate no significant occurrence of the recombinant event on the genome of LSDV isolates in China. Notably, the live virus challenge experiment demonstrated that the pathogenic characterization of this LSDV isolate belongs to a virulent strain. Collectively, we gain the first insight into the evolutionary trajectory, spatiotemporal transmission, and pathogenic characterization of circulating LSDV in China. This study provides a unique reference for risk assessment, guiding diagnostics, and prevention in epizootic and non-epizootic areas.

The comparative study revealed that the hTERT-CSF cell line was the most susceptible cell to the Lumpy skin disease virus infection among eleven cells

Lumpy skin disease virus (LSDV) is a rapidly emerging pathogen in Asia, including China. Improving the propagation of LSDV is important for diagnostics and vaccine production. Our study identified and compared the LSDV susceptibility of eleven standard cells using western blot, indirect immune-fluorescence assay, quantitative PCR, and 50% tissue culture infectious dose. Our finding revealed that the LSDV strain could infect five cell lines and show a cytopathic effect. Furthermore, the hTERT-CSF cell line had the highest level of virus in the five cell models, followed by BHK-21, MDBK, Vero, and hTERT-ST. Hence, hTERT-CSF could be used as a candidate cell line for basic and applied research, clinical application, and LSDV vaccine development, providing a vital reference in LSDV and other viruses.

Poxvirus Infections in Dairy Farms and Transhumance Cattle Herds in Nigeria

Lumpy Skin disease (LSD) is an economically important disease in cattle caused by the LSD virus (LSDV) of the genus Capripoxvirus, while pseudocowpox (PCP) is a widely distributed zoonotic cattle disease caused by the PCP virus (PCPV) of the genus Parapoxvirus. Though both viral pox infections are reportedly present in Nigeria, similarities in their clinical presentation and limited access to laboratories often lead to misdiagnosis in the field. This study investigated suspected LSD outbreaks in organized and transhumance cattle herds in Nigeria in 2020. A total of 42 scab/skin biopsy samples were collected from 16 outbreaks of suspected LSD in five northern States of Nigeria. The samples were analyzed using a high-resolution multiplex melting (HRM) assay to differentiate poxviruses belonging to Orthopoxvirus, Capripoxvirus, and Parapoxvirus genera. LSDV was characterized using four gene segments, namely the RNA polymerase 30 kDa subunit (RPO30), G-protein-coupled receptor (GPCR), the extracellular enveloped virus (EEV) glycoprotein and CaPV homolog of the variola virus B22R. Likewise, the partial B2L gene of PCPV was also analyzed. Nineteen samples (45.2%) were positive according to the HRM assay for LSDV, and five (11.9%) were co-infected with LSDV and PCPV. The multiple sequence alignments of the GPCR, EEV, and B22R showed 100% similarity among the Nigerian LSDV samples, unlike the RPO30 phylogeny, which showed two clusters. Some of the Nigerian LSDVs clustered within LSDV SG II were with commonly circulating LSDV field isolates in Africa, the Middle East, and Europe, while the remaining Nigerian LSDVs produced a unique sub-group. The B2L sequences of Nigerian PCPVs were 100% identical and clustered within the PCPV group containing cattle/Reindeer isolates, close to PCPVs from Zambia and Botswana. The results show the diversity of Nigerian LSDV strains. This paper also reports the first documented co-infection of LSDV and PCPV in Nigeria.

Cross-Protection of an Inactivated and a Live-Attenuated Lumpy Skin Disease Virus Vaccine against Sheeppox Virus Infections in Sheep

Sheeppox virus (SPPV) (genus Capripoxvirus, family Poxviridae) infections are a highly virulent and contagious disease of sheep with a high morbidity and mortality, especially in naïve populations and young animals. For the control of SPPV, homologous and heterologous live-attenuated vaccines are commercially available. In our study, we compared a commercially available live-attenuated lumpy skin disease virus (LSDV) vaccine strain (Lumpyvax) with our recently developed inactivated LSDV vaccine candidate regarding their protective efficacy against SPPV in sheep. Both vaccines were proven to be safe in sheep, and neither clinical signs nor viremia could be detected after vaccination and challenge infection. However, the local replication of the challenge virus in the nasal mucosa of previously vaccinated animals was observed. Because of the advantages of an inactivated vaccine and its heterologous protection efficacy against SPPV in sheep, our inactivated LSDV vaccine candidate is a promising additional tool for the prevention and control of SPPV outbreaks in the future.

The emergence of novel Iranian variants in sheeppox and goatpox viral envelope proteins with remarkably altered putative binding affinities with the host receptor

The outbreak of Sheep and goat pox (SGP) viral infections have increasingly been reported despite vaccinating the majority of sheep populations in Iran. The objective of this study was to predict the impacts of the SGP P32/envelope variations on the binding with host receptors as a candidate tool to assess this outbreak. The targeted gene was amplified in a total of 101 viral samples, and the PCR products were subjected to Sanger sequencing. The polymorphism and phylogenetic interactions of the identified variants were assessed. Molecular docking was performed between the identified P32 variants and the host receptor and the effects of these variants were evaluated. Eighteen variations were identified in the investigated P32 gene with variable silent and missense effects on the envelope protein. Five groups (G1-G5) of amino acid variations were identified. While there were no amino acid variations in the G1 (wild-type) viral protein, G2, G3, G4, and G5 proteins had seven, nine, twelve, and fourteen SNPs, respectively. Based on the observed amino acid substitutions, multiple distinct phylogenetic places were occupied from the identified viral groups. Dramatic alterations were identified between G2, G4, and G5 variants with their proteoglycan receptor, while the highest binding was revealed between goatpox G5 variant with the same receptor. It was suggested that the higher severity of goatpox viral infection originated from its higher affinity to bind with its cognate receptor. This firm binding may be explained by the observed higher severity of the SGP cases from which G5 samples were isolated.

Generation and application of immortalized sertoli cell line from sheep testis

Primary sheep testicular Sertoli cells (STSCs) are ideal for investigating the molecular and pathogenic processes of capripoxvirus. However, the high cost of isolation and culture of primary STSCs, time-consuming operation, and short lifespan greatly limit their real-world application. In our study, the primary STSCs were isolated and immortalized by transfection of a lentiviral recombinant plasmid containing simian virus 40 (SV40) large T antigen. Androgen-binding protein (ABP) and vimentin (VIM) protein expression, SV40 large T antigen activity, proliferation assays, and apoptosis analysis results showed that immortalized large T antigen STSCs (TSTSCs) still had the same physiological characteristics and biological functions as primary STSCs. Moreover, immortalized TSTSCs had strong anti-apoptosis ability, extended lifespan, and enhanced proliferative activity compared to primary STSCs, which had not transformed in vitro and showed any signs of malignancy phenotype in nude mice. Besides, immortalized TSTSCs were susceptible to goatpox virus (GTPV), lumpy skin disease virus (LSDV), and Orf virus (ORFV). In conclusion, immortalized TSTSCs are useful in vitro models to study GTPV, LSDV, and ORFV in a wide range of ways, suggesting that it can be safely used in virus isolation, vaccine and drug screening studies in future.

An Extensive Examination of the Warning Signs, Symptoms, Diagnosis, Available Therapies, and Prognosis for Lumpy Skin Disease

The lumpy skin disease virus (LSDV) infects cattle and buffalo and causes lumpy skin disease (LSD). It affects the lymph nodes of the sick animals, causing them to enlarge and appear as lumps (cutaneous nodules) that are 2–5 cm in diameter on their heads, necks, limbs, udders, genitalia, and perinea. A high temperature, a sharp drop in milk supply, discharge from the eyes and nose, salivation, a loss of appetite, depression, damaged hides, and emaciation are further warning signs and symptoms. As per the Food and Agriculture Organization (FAO), the incubation period, or the time between an infection and symptoms, is approximately 28 days. Infected animals can transfer the virus by direct contact with the vectors, direct virus secretion from mouth or nose, shared feeding and watering troughs, and even artificial insemination. The World Organization for Animal Health (WOAH) and the FAO both warn that the spread of illnesses could lead to serious economic losses. This illness reduces cow’s milk production because oral ulcers make the animal weak and lead them to lose their appetite. There are many diagnostics available for LSDV. However, very few tests yield accurate findings. The best methods for preventing and controlling the lumpy skin condition include vaccination and movement restrictions. As a specific cure is not available, the only available treatment for this illness is supportive care for cattle. Recently, India has developed a homologous, live-attenuated vaccine, Lumpi-ProVacInd, which is specifically intended to protect animals against the LSD virus. This study’s primary goal is to accumulate data on symptoms, the most accurate method of diagnosis, treatments, and controls to stop infections from spreading as well as to explore future possibilities for the management of LSDV.

Duration of Immunity Induced after Vaccination of Cattle with a Live Attenuated or Inactivated Lumpy Skin Disease Virus Vaccine

Vaccines have proven themselves as an efficient way to control and eradicate lumpy skin disease (LSD). In addition to the safety and efficacy aspects, it is important to know the duration for which the vaccines confer protective immunity, as this impacts the design of an efficient control and eradication program. We evaluated the duration of immunity induced by a live attenuated vaccine (LSDV LAV) and an inactivated vaccine (LSDV Inac), both based on LSDV. Cattle were vaccinated and challenged after 6, 12 and 18 months for LSDV LAV or after 6 and 12 months for the LSDV Inac. The LSDV LAV elicited a strong immune response and protection for up to 18 months, as no clinical signs or viremia could be observed after a viral LSDV challenge in any of the vaccinated animals. A good immune response and protection were similarly seen for the LSDV Inac after 6 months. However, two animals developed clinical signs and viremia when challenged after 12 months. In conclusion, our data support the annual booster vaccination when using the live attenuated vaccine, as recommended by the manufacturer, which could potentially even be prolonged. In contrast, a bi-annual vaccination seems necessary when using the inactivated vaccine.

Insights into the Prognostic Role of Serum Interleukin-6 and Hematobiochemical Alterations in Cattle during Recent Outbreaks of Lumpy Skin Disease in Lodhran District, Pakistan

Lumpy skin disease (LSD) is a highly infectious disease of cattle caused by a virus of the Poxviridae family, genus Capripoxvirus. The present study was designed to determine the prognostic ability of serum IL-6 in LSD using a binary logistic regression model at baseline sampling. A 17-day cohort study was conducted on a recent outbreak of LSD among cattle in the Lodhran District of Punjab, Pakistan. Infected cattle were divided into two categories based on their clinical status on day 17 as recovered (n = 33) or unrecovered (n = 17). Nodular lesions and scab specimens (n = 50) were used for the isolation of the lumpy skin disease virus and were confirmed by PCR. In recovered animals, hematological results showed marked leukocytosis, eosinophilia, lymphocytosis, neutrophilia, and monocytopenia. However, marked erythrocytosis, leukopenia, and thrombocytopenia were observed in the unrecovered animals at the final sampling point of the study. Serum levels of total protein, albumin, and glucose were significantly higher in the recovered animals. Meanwhile, aspartate aminotransferase, alkaline phosphatase, lactate dehydrogenase, creatinine phosphokinase, total bilirubin, and direct bilirubin were found considerably higher in the unrecovered group. Receiver-operating characteristic curve analysis for serum IL-6 at baseline predicts the extended clinical conditions at the cut-off value of 85.16 pg/mL (55% specificity, 94% sensitivity, area under the curve 0.8039, respectively). In conclusion, the disease-induced hematological and biochemical alterations were significantly ameliorated in the recovered animals. In addition, the study revealed that serum IL-6 can be used as a valid marker for predicting the clinical worsening of LSD in cattle.

The Characterization and Differentiation of Recombinant Lumpy Skin Disease Isolates Using a Region within ORF134

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.

Seroprevalence and associated risk factors of pox infection among sheep and goats in selected districts of Afar region, Ethiopia

Background

Sheep and goat pox virus infection is highly devastating viral disease of small ruminants that cause severe production losses in sheep and goats in Ethiopia and also limits international trade. A cross-sectional study was employed with the objective to estimate the seroprevalence of pox infection and to assess associated risk factors during the study period, February to April, 2020. A total of 384 serum samples were collected from apparently healthy sheep and goats. Serum neutralization test was used to detect the presence of antibodies against pox virus at national veterinary institute. Descriptive statistics, univariable and Multivariable logistic analyses were used in this study.

Results

The overall animal level seroprevalence of sheep and goat pox virus was found to be 15.36% (n = 59/384) and species level prevalence rate was found to be 14.5% (n = 16/110) in sheep and 15.69% (n = 43/274) in goats in the study areas. Among the associated factors considered in this study, sex (P = 0.010), age (P = 0.012) and herd size (P = 0.029) were found to be statistically associated with seropositivity of pox infection in multivariable logistic regression. The odds of seropositivity in female animals were 3.9 times more likely to develop pox infection than male animals (AOR = 2.2; 95% CI = 1.203-4.015%) and the odds of young animals were 2.14 times more likely to be seropositive to pox infection than old aged animals (AOR = 2.14; 95% CI = 1.169-3.633%). Moreover, the odds of large-sized flocks of animals were 3.10 times more likely to be seropositive to pox disease than small-sized flocks (AOR = 3.10; 95% CI = 1.30-4.42%).

Conclusion

This study finding revealed that sheep and goat pox virus is prevalent and widespread diseases of small ruminant in afar region. Therefore, further study should be carried out to estimate region wise magnitude of the disease and control measures should be put in place to minimize the economic losses associated with this disease.

Improved safety profile of inactivated Neethling strain of the Lumpy Skin Disease Vaccine

The Lumpy Skin Disease Virus (LSDV) Neethling vaccine strains have been used for decades for prophylactic immunization of domestic ruminants against the disease. Commercial products against Lumpy skin disease are supplied as live attenuated vaccines and often are associated with adverse reactions warranting studies towards development of safe and efficacious vaccine alternatives. The present study was designed to investigate the ability of Montanide™ Gel 01 PR adjuvanted inactivated Neethling vaccine strain of the lumpy skin disease to induce immune response in rabbits. Complete virus inactivation was achieved following treatment of live vaccine strain with binary ethyleneimine (BEI) at 2 mM final concentration. Inactivated virus antigen, formulated with Montanide™ Gel 01 was injected at 1,00E + 05 and 1,00E + 06 TCID₅₀ per dose in rabbits. The second injection with same vaccine dosages was administered 21 days after the primary vaccination. Rabbits that received a 1,00E + 05 TCID₅₀/dose of inactivated LSDV vaccine formulation induced maximum neutralizing antibody titres on day 13 post second vaccinations. Rabbits vaccinated and prime boosted with the 1,00E + 06 TCID₅₀/dose of inactivated LSDV vaccine formulation, induced neutralizing antibody titres on day 14 after first vaccination. The maximum antibody titres for the 1,00E + 06 TCID₅₀/dose of the inactivated LSDV vaccine formulation was obtained on day 35 post vaccination. The 1,00E + 06 TCID₅₀ dose of the inactivated LSDV vaccine Montanide™ Gel-01 PR formulation induced higher neutralizing antibodies. The Montanide^TM Gel-01 PR offers safer profile to oil adjuvants and can be developed further to protect target animals against LSDV in non-endemic areas.

Lumpy Skin Disease: An Economically Significant Emerging Disease

Lumpy skin disease (LSD) is a severe viral disease of cattle caused by the lumpy skin disease virus (LSDV), a member of the Capripoxvirus genus of the poxviridae family. Fever and flat disk-like skin nodules on the skin characterize the disease. It can also lead to death and significant economic losses, especially in herds, that have never been exposed to the virus. Blood-feeding insects, such as specific types of flies, mosquitoes, and ticks, are thought to be the primary vectors of LSDV transmission. Most African and middle eastern countries have a high prevalence of lumpy skin disease. The disease extended to southeast Europe, the Balkans, and the Caucasus in 2015 and 2016 and is still spreading throughout Asia. The World Organization for Animal Health [WOAH] has designated LSD as a notifiable illness due to the likelihood of fast transmission. The rapid spread of disease in formerly disease-free areas emphasizes the need to know the disease epidemiology and the virus’s interaction with its host. This chapter aims to provide the latest developments in the etiology, epidemiology, diagnosis, and control of LSD.

The Development of a Real-Time PCR Assay for Specific Detection of the NISKHI Sheep Pox Vaccine Virus Strain DNA

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.

Clinical Epidemiology, Pathology, and Molecular Investigation of Lumpy Skin Disease Outbreaks in Bangladesh during 2020-2021 Indicate the Re-Emergence of an Old African Strain

Lumpy skin disease (LSD) emerged in Bangladesh in mid-2019, leading to great economic losses for cattle farmers. This study describes the recent occurrence of the LSDV in Bangladesh and examines the clinical manifestation of the disease in local cattle breeds, characteristic epidemiological features, and pathological findings in affected animals. In addition, a full-genome sequencing of two local LSDV isolates was carried out. A total of 565 animals from 88 households were investigated, and 165 samples (skin lesions, saliva, nasal discharge, feces, and milk) were collected for virus detection. Pathology and immunohistochemistry were performed on nodule biopsies. Fever, nodular skin lesions, and swelling of the joints were the most common clinical manifestations. Skin lesions had a higher concentration of viral DNA compared to other sample types and were therefore selected for virus isolation and characterization. Pathology of the LSD skin nodules comprised a granulomatous reaction in the dermis and hypodermis that extended to the surrounding tissues. Development of the skin lesions started with swelling of keratinocytes with cytoplasmic vacuolation, vasculitis, panniculitis, thrombosis, and infarction. Altogether, the LSDV produced transmural, hemorrhagic, necrotizing, proliferative and ulcerative dermatitis. The LSD viral antigen was detected occasionally in the macrophages, epithelial cells, and vascular smooth muscle cells. The complete genome sequence analysis revealed that the two Bangladeshi field strains (BD-V392.1 and BD-V395.1) were distinct from the contemporary field strains and were closely related to the ancestral African Neethling strain. The findings of this study will improve the diagnosis, monitoring, and control of LSD in Bangladesh.

Epidemiological investigation of lumpy skin disease outbreaks in Bangladeshi cattle during 2019-2020

Lumpy skin disease (LSD) is an acute infectious viral disease of cattle with a wide distribution that emerged in Bangladesh in 2019, causing huge economic losses. This study was undertaken to investigate the epidemiological features of LSD emergence in nine districts of Bangladesh between December 2019 and December 2020. A total of 8215 cattle from 603 herds were investigated and LSD was diagnosed based on the characteristic clinical findings. A standard questionnaire was administered to collect herd-level data including location, herd size, number of LSD-infected cattle, number died due to LSD, farm type, season, house type, vector presence, sanitation and fly repellent use. Similarly, data on clinical signs, sex, age, animal class and breed of the LSD-infected cattle were also recorded. The herd-level attack risk (%) and mortality risk (%) were calculated based on the number of infected and dead cattle, respectively, as a proportion of total cattle. The herd-level risk factors for LSD were identified using a multivariable Poisson regression model. The most common clinical signs were skin nodules (100%), fever (97.9%) and depression with anorexia and weight loss (97.9%). Crossbred (84.9%) and female (72.2%) cattle were mostly affected by LSD. The overall LSD attack risk, mortality risk and case fatality were 26.5%, 0.26% and 0.97%, respectively. The LSD attack risk was significantly higher in small herds (risk ratio: [RR] 1.39; 95% CI: 1.27; 1.53) than large herds. In addition, significantly higher LSD attack risk was observed in semi-intensive management systems (RR = 1.29; 95% CI: 1.01; 1.64) than intensive management systems. Moreover, it was also significantly higher in hut (RR = 1.81; 95% CI: 1.12; 2.92), temporary (RR = 1.62; 95% CI: 1.21; 2.17) and tin-shed houses (RR = 1.29; 95% CI: 1.11; 1.51) than in semi-building houses. To the best of our knowledge, this is the first detailed epidemiological study of LSD emergence in South Asia. Female crossbred cattle in small herds under semi-intensive management should be prioritized for LSD surveillance and vaccination to prevent further outbreaks and control the impact of the disease in Bangladesh.

Lumpy Skin Disease Outbreaks in Africa, Europe, and Asia (2005-2022): Multiple Change Point Analysis and Time Series Forecast

LSD is an important transboundary disease affecting the cattle industry worldwide. The objectives of this study were to determine trends and significant change points, and to forecast the number of LSD outbreak reports in Africa, Europe, and Asia. LSD outbreak report data (January 2005 to January 2022) from the World Organization for Animal Health were analyzed. We determined statistically significant change points in the data using binary segmentation, and forecast the number of LSD reports using auto-regressive moving average (ARIMA) and neural network auto-regressive (NNAR) models. Four significant change points were identified for each continent. The year between the third and fourth change points (2016-2019) in the African data was the period with the highest mean of number of LSD reports. All change points of LSD outbreaks in Europe corresponded with massive outbreaks during 2015-2017. Asia had the highest number of LSD reports in 2019 after the third detected change point in 2018. For the next three years (2022-2024), both ARIMA and NNAR forecast a rise in the number of LSD reports in Africa and a steady number in Europe. However, ARIMA predicts a stable number of outbreaks in Asia, whereas NNAR predicts an increase in 2023-2024. This study provides information that contributes to a better understanding of the epidemiology of LSD.

[Determination of the optimal immunizing dose of heterologous goat pox virus vaccine (Poxviridae: <I>Chordopoxvirinae: Capripoxvirus</I>) against lumpy skin disease]

INTRODUCTION

Lumpy skin disease (LSD), sheep pox and goat pox are dangerous diseases of domestic ruminants. Representatives of the genus of capripoxviruses are antigenically similar and can be used as a vaccine for three infections, as in the case of representatives of the genus of orthopoxviruses, which includes viruses of smallpox, monkeypox, and cowpox, that all belong to a single family Poxviridae.

MATERIALS AND METHODS

In this study, the vaccine strain G20-LKV of the goat pox virus and the virulent strain RIBSP2019/K of the LSD virus were used. The experiments were carried out on clinically healthy cattle of the Kazakh White-headed breed, aged six to eight months. Virological and serological research methods were used in the work.

RESULTS

All immunized animals that received different doses of the vaccine showed resistance to the infection challenge, without showing any clinical signs of the disease. In animals that received the lowest doses of the vaccine 15,000, 30,000 and 40,000 TCID50, no adverse events, skin and temperature reactions were observed at the injection site. Those vaccinated with high doses of the vaccine had a local reaction in the form of swelling at the site of vaccine administration. Control animals infected with a virulent virus showed clinical signs of the cattle lumpy skin disease .

CONCLUSION

The vaccine, prepared based on the "G20-LKV" strain of the goat virus, is protective for cattle against infection with a virulent LSD virus at immunizing doses from 15,000 to 80,000 TCID50, which are dependent on the LSD epizootic situation in particular region.

Temporal dysregulation of genes in Lamb testis cell during sheeppox virus infection

The present study was aimed to elucidate the host-virus interactions using RNA-Seq analysis at 1h and 8h of post-infection of SPPV in LTC. The differentially expressed genes (DEGs) and the underlying mechanisms linked to the host immune responses were obtained. The protein-protein interaction (PPI) network analysis and Ingenuity pathway analysis (IPA) illustrated the interaction between the DEGs and their involvement in cell signalling responses. Highly connected hubs viz. AURKA, CHEK1, CCNB2, CDC6, and MAPK14 were identified through PPI network analysis. IPA analysis showed that IL-6 and ERK5 mediated signalling pathways were highly enriched at both time points. The TP53 gene was identified to be the leading upstream regulator that directly responded to SPPV infection, resulting in downregulation at both time points. The study provides an overview of how the lamb testis genes and their underlying mechanisms link to growth and immune response during SPPV infection.

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 epidemiology of lumpy skin disease outbreak in Odisha, India

Lumpy skin disease virus (LSDV) is the causative agent of lumpy skin disease (LSD) which is a member of Capripoxvirus. It is an economically critical transboundary disease affecting cattle. This study records an LSD outbreak in Ganjam district of Odisha, India during August 2020. The epidemiological data were analysed and LSDV was genetically characterized. Out of the 452 animals clinically examined (59 farms), 63 animals were clinically affected with LSD, with a total morbidity rate of 13.93%. The morbidity rates in the surveyed villages (n = 10) varied from 5.55 to 21.62%. The multivariable logistic regression analysis showed that grazing of animals (P = 0.013; OR: 2.04; 95% CI: 1.16-3.57) and age of cows > 3 years old (P = 0.001; OR: 2.90; 95% CI: 1.65- 5.07) were potential risk factors for the presence of LSD. Out of the 53 clinically suspected animals' samples, 18 samples (33.96%) were found positive for both the P32 and F genes of Capripoxvirus by PCR. Phylogenetic analysis of the P32 gene of LSDV (MW147486) showed 100% similarity with other isolates from India, Bangladesh, Egypt and Saudi Arabia. Additionally, phylogenetic analysis of the F gene of LSDV (MW147485) revealed a similarity of 97.99%, with Odisha India (MT074110) isolate and located in the same cluster with other Indian isolates.

Seroprevalence and Associated Risk Factors of Lumpy Skin Disease of Cattle in Selected Districts of Afar Region, Ethiopia

Background

Lumpy skin disease (LSD) is one of Ethiopia's most economically significant transboundary livestock illnesses. The disease has a significant economic impact on pastoral household livestock owners, who rely significantly on their cattle as a source of income.

Methods

A cross-sectional study was undertaken in selected districts of Afar region from November 2018 to May 2019 primarily intended to estimate the prevalence of lumpy skin disease serologically in local Afar cattle as well as identify potential associated factors. A multistage sampling method was employed to select study districts, peasant association, herd size and study units. A total of 384 sera were processed using serum neutralization test (SNT) method to detect antibodies against lumpy skin disease virus. Relevant data were refined and further analyzed using stata version 14.

Results

In the study districts, the overall animal level seroprevalence was found to be 7.6% (N = 29/384; 95% confidence interval: 4.90-10.20) and the overall herd level prevalence was found to be 20.8% (n = 15/72; 95% confidence interval: 11.42-30.18). Only district was shown to be statistically significant (P = 0.004) in terms of LSD occurrence among the relevant factors studied. Cattle in Chifra district were 20.18 times more likely to contract LSD infection than cattle in Dubti district, when Asayita district was used as the reference group.

Conclusion

The present study finding confirmed the presence of the disease in the study districts of afar region and coordinated intervention set to be in place.

A highly adaptable platform powered by CRISPR-Cas12a to diagnose lumpy skin disease in cattle

Lumpy skin disease (LSD) in cattle, a transboundary viral disease of cattle once restricted to Africa, has been spreading to many European and Asian countries in the past decade with huge economic losses. This emerging worldwide threat to cattle warrants the development of diagnostic methods for accurate disease screening of suspected samples to effectively control the spread of LSD. In this study, we integrated pre-amplification and three kinds of sensor systems with CRISPR and therefore established an LSD diagnosis platform with highly adaptable and ultra-sensitive advantages. It was the first CRISPR-powered platform that could identify lumpy skin disease virus from vaccine strains of goat pox virus and sheep pox virus. Its limit of detection (LOD) was one copy/reaction after introducing PCR or recombinase-aided amplification (RAA). Moreover, this platform achieved a satisfactory overall agreement in clinical diagnoses of 50 samples and its reproducibility and accuracy were superior to other qPCR methods we tested. The whole diagnostic procedure, from DNA extraction to the results, could complete in 5 h with a total cost of 1.7-9.6 $/test. Overall, this CRISPR-powered platform provided a novel diagnostic tool for portable, ultra-sensitive, rapid, and highly adaptable disease screening of LSD and may be an effective method to control this transboundary disease's spread.

Isolation and molecular characterization of lumpy skin disease virus from hard ticks, Rhipicephalus (Boophilus) annulatus in Egypt

BACKGROUND

Lumpy skin disease (LSD), a disease of cattle and buffaloes, has recently become widely prevalent in Egypt. The aim of this study was to ascertain the potential role of Rhipicephalus (Boophilus) annulatus ticks in the transmission of this disease. Samples collected from suspected lumpy skin disease virus (LSDV) infected cows that had previously been vaccinated with the Romanian sheep pox virus (SPPV) in various Egyptian governorates were obtained between May to November over two consecutive years, namely 2018 and 2019. Ticks were morphologically identified and the partial cytochrome oxidase subunit I gene (COI) were sequenced, revealing that they were closely related to R. (Boophilus) annulatus. The G-protein-coupled chemokine receptor (GPCR) gene of the LSDV was used to test hard ticks.

RESULTS

Two positive samples from Kafr El-Sheikh province and one positive sample from Al-Behera province were reported. BLAST analysis revealed that the positive samples were closely related to the Kazakhstani Kubash/KAZ/16 strain (accession number MN642592). Phylogenetic analysis revealed that the GPCR gene of the LSDV recently circulating in Egypt belongs to a global cluster of field LSDV with a nucleotide identity of 98-100%. LSDV isolation was successfully performed four days after inoculation using 9 to 11-day-old embryonated chicken eggs showing characteristic focal white pock lesions dispersed on the choriallantoic membrane after three blind passages. Intracytoplasmic inclusion bodies, cell rupture, vacuoles in cells, and virus particles ovoid in shape were demonstrated by electron microscopy.

CONCLUSION

In this study the role of hard ticks in the transmission of the LSDV to susceptible animals in Egypt was revealed and confirmed by various methods.

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.

A field study evaluating the humoral immune response in Mongolian sheep vaccinated against sheeppox virus

Sheeppox is a transboundary disease of small ruminants caused by infection with the capripoxvirus sheeppox virus. Sheeppox is found in Africa, the Middle East and Asia and is characterized by fever, multifocal cutaneous raised lesions and death. Vaccination with live attenuated capripoxvirus (CPPV) strains is an effective and widely used strategy to contol sheeppox outbreaks; however, there are few reports of post-vaccination field surveillance studies. This study used a commercially available enzyme-linked immunosorbent assay (ELISA) to examine quantitative and temporal features of the humoral response of sheep vaccinated with a live-attenuated CPPV strain in Mongolia. Four hundred samples were tested using the ELISA commercial kit, and a subset of 45 samples were also tested with a virus neutralization test (VNT). There was substantial agreement between the VNT and ELISA tests. Antibodies to CPPV were detected between 40 and 262 days post-vaccination. There was no significant difference between serological status (positive/negative) and sex or age; however, an inverse correlation was found between the length of time since vaccination and serological status. Animals between 90 and 180 days post-vaccination were more likely to be positive than animals greater than 180 days post-vaccination. Our results show that a commercial CPPV ELISA kit is a robust and reliable assay for post-CPPV vaccination surveillance in resource-restricted settings and provide temporal parameters to be considered when planning sheeppox post-vaccination monitoring programmes.