Capripoxviruses are the causative agents of sheeppox, goatpox, and lumpy skin disease (LSD) in cattle, which cause economic losses to the livestock industry in Africa and Asia. Capripoxviruses are currently controlled using several live attenuated vaccines. It was previously demonstrated that a lumpy skin disease virus (LSDV) field isolate from Warmbaths (WB) South Africa, ORF 005 (IL-10) gene-deleted virus (LSDV WB005KO), was able to protect sheep and goats against sheeppox and goatpox. Subsequently, genes encoding the protective antigens for peste des petits ruminants (PPR) and Rift Valley fever (RVF) viruses have been inserted in the LSDV WB005KO construct in three different antigen forms (native, secreted, and fusion). These three multivalent vaccine candidates were evaluated for protection against PPR using a single immunization of 104 TCID50 in sheep. The vaccine candidates with the native and secreted antigens protected sheep against PPR clinical disease and decreased viral shedding, as detected using real-time RT-PCR in oral and nasal swabs. An anamnestic antibody response, measured using PPR virus-neutralizing antibody response production, was observed in sheep following infection. The vaccine candidates with the antigens expressed in their native form were evaluated for protection against RVF using a single immunization with doses of 104 or 105 TCID50 in sheep and goats. Following RVF virus infection, sheep and goats were protected against clinical disease and no viremia was detected in serum compared to control animals, where viremia was detected one day following infection. Sheep and goats developed RVFV-neutralizing antibodies prior to infection, and the antibody responses increased following infection. These results demonstrate that an LSD virus-vectored vaccine candidate can be used in sheep and goats to protect against multiple viral infections.

An epidemiological study spanning twelve years has revealed that sheeppox disease is both widespread and endemic, predominantly surging during the winter and summer seasons. This investigation focused on sheeppox across 11 field outbreaks, involving 889 animals from non-migratory flocks across six districts in Karnataka, in the southern peninsula of India. Among these, 105 animals exhibited clinical signs suggestive of sheeppox, such as lesions on the body, and 95 cases were confirmed through PCR testing. The overall positivity rate for sheeppox stood at 10.68% (95 out of 889 animals). The incidence of sheeppox was notably higher in animals aged between 1 and 2 years and was more prevalent in females. Affected animals displayed symptoms including respiratory distress, weakness, fever, loss of appetite, depression, and various skin lesions ranging from papular to pock lesions across their bodies. There was a significant increase in total leukocyte count, while hemoglobin levels, red blood cell counts, and hematocrit values significantly decreased. On gross examination, sheeppox lesions, varying from vesicular to nodular forms, were predominantly found on hairless areas of the body. Microscopic examination of skin lesions revealed extensive changes, such as hyperkeratosis, parakeratosis, acanthosis, hydropic degeneration, and necrosis of epithelial cells, along with characteristic intracytoplasmic viral inclusions. The lungs exhibited type-II pneumocyte hyperplasia and proliferative bronchiolitis, also with intracytoplasmic inclusions. Confirmation of the sheeppox virus was achieved through PCR and subsequent sequence analysis. Phylogenetic analysis of the full-length P32 and RPO30 gene demonstrated homology with sheeppox isolates from various parts of India and neighboring countries, indicating that Indian sheeppox viruses are highly lineage-specific and correlate with the host of origin. Based on these findings, it is recommended to implement a homologous vaccination strategy, utilizing selective host/viral strains to enhance protection in susceptible animals.

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.

The genus Capripoxvirus belongs to the Poxviridae family. The sheeppox, goatpox, and lumpy skin disease viruses are three species of this genus with 96% identity in their genomes. These are financially devastating viral infections among cattle, which cause a reduction in animal products and lead to a loss in livestock industries. In the current study, the phylogenetic analysis was carried out to reveal the evolutionary relationships of Capripoxvirus species (i.e., sheeppox virus (SPPV), goatpox virus (GTPV), and lumpy skin disease virus (LSDV)) with other viruses from the Poxviridae family with >96% query coverage to find the similarity index among all members. The three viruses (i.e., SPPV, GTPV, and LSDV) joined the clade of Capripoxvirus of the Poxviridae family in the phylogenetic tree and exhibited close evolutionary relationships. The multiple sequence alignment using ClustalOmega revealed significant variations in the protein sequences of the DNA-dependent RNA polymerase of SPPV, GTPV, and LSDV. The three-dimensional structures of five selected bee peptides and DNA-directed RNA polymerase of SPPV, GTPV, and LSDV were predicted using trRosetta and I-TASSER and used for molecular docking and simulation studies. The protein-protein docking was carried out using HADDOCK server to explore the antiviral activity of peptides as honey bee proteins against SPPV, GTPV, and LSDV. In total, five peptides were docked to DNA-directed RNA polymerase of these viruses. The peptides mellitin and secapin-1 displayed the lowest binding scores (-106.9 +/- 7.2 kcal/mol and -101.4 +/- 11.3 kcal/mol, respectively) and the best patterns with stable complexes. The molecular dynamics simulation indicated that the complex of protein DNA-dependent RNA polymerase and the peptide melittin stayed firmly connected and the peptide binding to the receptor protein was stable. The findings of this study provide the evidence of bee peptides as potent antimicrobial agents against sheeppox, goatpox, and lumpy skin disease viruses with no complexity.

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.

This study aimed to investigate a sheeppox outbreak in a highly susceptible naive sheep population in Kharsit village, Gharbia Governorate, Egypt. Moreover, to compare commercial sheeppox vaccines, the Romanian strain and RM-65 vaccines, as emergency vaccination against sheeppox under field conditions. In December 2018, a sheeppox outbreak occurred in a flock of 65 sheep upon the purchase of an apparently healthy ewe from outside the village. This ewe showed a systemic disease with cutaneous lesions after a few days, thereafter more cases began to appear. Cutaneous lesions in other sheep in the flock in the form of macules, papules, and scabs were common in wool-less areas of the body, in addition to fever and respiratory disorders. Postmortem findings revealed the congestion of visceral organs with apparent gross pathology of the lung. Biopsies of cutaneous lesions and visceral organs were collected, and sheeppox was identified by histopathology and transmission electron microscopy, which showed the existence of sheeppox cells and intracytoplasmic brick-shape sheeppox virions. The Romanian strain and RM-65 vaccines were used for the emergency vaccination for two different groups of animals and the third group was left as a control group. Serum samples were collected before vaccination as well as 21 days post-vaccination, and serum protein fractionation analysis was performed for all groups. The outbreak ended after 2.5 months, the cumulative incidence was 66.2%, and the overall case fatality was 51.1%. There was significantly higher protection against sheeppox infection and mortalities among RM-65 vaccine immunized group compared to Romanian strain vaccine-immunized animals at p < 0.05. RM-65-vaccinated animals did not show sheeppox cases or mortalities, compared to Romanian strain-vaccinated animals, which had mild pox signs in 78% of animals and case fatality of 35.7%. The serum protein analysis also indicated the superior performance of the RM-65 vaccine; it increased the level of α1-globulin and β-globulin compared to the Romanian strain, which increased the level of β-globulin only. The current study shows a better performance of the tested RM-65 than the Romanian strain vaccine for emergency vaccination against sheeppox under field conditions. These findings point to the validity of emergency vaccination against sheeppox and the importance of the comparative field evaluation of vaccines; however, wide-scale studies are required for further evaluation. Future investigation of whether the Romanian strain itself or vaccine-production-related issues are responsible for these findings is required.

Goatpox, sheeppox, and peste-des-petits-ruminants (PPR) are economically important virus diseases affecting goats and sheep, which often cause coinfection/comorbidities in the field. Coinfection with these viruses leads to enhanced infection in natural scenarios in terms of morbidities and mortalities. Currently, individual live attenuated vaccines are being used to mitigate these diseases and research on combination vaccines for these diseases is encouraging. For the preparation of combination vaccines, vaccine strains of the peste-des-petits-ruminants virus (PPRV), goatpox virus (GTPV), and sheeppox virus (SPPV) are grown separately and GTPV + PPRV are mixed for vaccination of goats, and PPRV + SPPV for sheep. Growing capripox and PPRV strains in the same cells simultaneously without the titer loss will save the time and cost of production. In the current study, we have evaluated the coinfection kinetics of capripox virus and a PPRV using a candidate GTPV vaccine strain (originally caused infection in both goats and sheep in the field) and PPRV/Sungri/96 (vaccine strain) in Vero cells. At high multiplicity of infection (MOI), PPRV was excluded from coinfection by GTPV, whereas at a low multiplicity coexistence/accommodation was observed between PPRV and GTPV without loss of the titer. The results shed light on the possibility of the production of two vaccine strains in the same cells using the coinfection model economically.

Sheep and goatpox are caused by pox virus and economically very important. The study was conducted to estimate the economic losses due to sheep and goatpox, to estimate the morbidity and mortality as well as the transmission parameters. A cross sectional study was conducted in Chifra districts of Afar region from July 2020 to December 2020 using questioner survey. For the estimation of the economic impacts and the transmission parameters of the outbreak, a data was collected at the end of the outbreak through a direct face to face interview. Transmission parameters were estimated based on a final size approach. Whereas, economic impacts were estimated descriptively using different formulas based on the type of losses. The overall morbidity, mortality and case fatality of sheep and goatpox were 51.6%, 2.0%, and 3.9%, respectively. The average flock level losses due to treatment cost, mortality and abortion were 320.3, 1250 and 1195.6 Ethiopian birr (ETB), respectively. The outbreak caused a total of 63617 ETB losses in the district. The highest loss was due to mortality (28750ETB), whereas the least loss was due to treatment cost (7367ETB). The outbreak had 0.14 and 1.41 transmission rate parameters per day and basic reproduction ratio, respectively. There was a significant difference in the transmission of the infection between individual animals (p < 0.001). To limit the economic losses due to this disease, the farmers should give more attention towards this disease and a systematic control program comprising vaccination and limitation of movement of sheep and goat should be implemented to alleviate the losses due to sheep and goatpox.

Capripoxvirus diseases are listed as reportable diseases by World Organization for Animal Health (OIE). Lumpy skin disease virus (LSDV) and sheeppox virus (SPPV), which can only be distinguished by molecular analysis, cause moderately, severe, or sometimes fatal infections in cattle and sheep. Even though vaccines are the most effective way to control the infection, their effectiveness may decrease in some cases. Therefore, it is significant to explore antiviral drugs against these diseases along with the vaccine. This study aimed to investigate the antiviral efficiency of ivermectin (IVM) at different stages of in vitro replication of LSDV and SPPV. For this purpose, viral titers (TCID50/mL) of the viruses not treated with IVM (0.0 μM) and treated with non-cytotoxic concentrations of IVM (1.0 and 2.5 μM) were compared during a nine-day (216 h) post-infection period by viral titration assay. At 2.5 μM concentrations of IVM, the mean viral titer was significantly (P<0.05) reduced by approximately three logs for the replication stage of LSDV and SPPV. To evaluate the antiviral activity of IVM against LSDV and SPPV by treatment at the virus attachment and penetration stages, the titers of the virus either untreated or treated with 2,5 μM IVM were compared by virus titration assay. The number of infectious virions for LSDV and SPPV were decreased by 99.82% and 99.87% at the viral replication stage, 68.38% and 25.01% at the attachment stage, and 57.83% and 0.0% at the penetration stage, respectively. It was determined that ivermectin is statistically more effective on LSDV than SPPV at the virus attachment and penetration stages (P<0.05). This study found that the drug IVM can inhibit capripoxviruses, including LSDV and SPPV at various stages of the propagation. Moreover, this research predicted the in vitro antiviral ability of IVM against capripoxvirus infections for the first time.

An outbreak of sheeppox was investigated in a cluster of villages situated in Western Himalayan ranges of a Northern Indian state. Non-migratory sheep (n = 80) of native breeds namely Gaddi and Rampur Bushair were infected and 15 have died. The outbreak started after a few animals contracted the disease during the summer grazing period at the highland pastures from migrating flocks of sheep. This initial outbreak resulted in a further spreading of the disease into the valley. Clinical examination revealed varying degree of cutaneous papular lesions and respiratory distress. Upon necropsy, visceral lesions in the lungs, trachea and kidneys were also found. Clinical and morbid samples were found positive for sheeppox virus using group specific P32 gene and I3L gene based multiplex PCR differentiating sheeppox and goatpox viruses. Histopathological, hematological and blood biochemical analysis also supported the pathology of an acute viral infection. The causative sheeppox virus strain was isolated using lamb testicular cell culture and phylogenetic analysis, based upon P32 and RPO30 genes, showed its clustering with other Indian strains reported from neighboring states. This study demonstrated the spread of sheeppox virus to new niches by migratory sheep flocks leading to establishment of endemic infections in many new pockets of higher Western Himalayas.