Comparative sequence analysis of major envelope protein gene (B2L) of Indian orf viruses isolated from sheep and goats

Designing a multi-epitope subunit vaccine against Orf virus using molecular docking and molecular dynamics

Orf virus (ORFV) is an acute contact, epitheliotropic, zoonotic, and double-stranded DNA virus that causes significant economic losses in the livestock industry. The objective of this study is to design an immunoinformatics-based multi-epitope subunit vaccine against ORFV. Various immunodominant cytotoxic T lymphocytes (CTL), helper T lymphocytes (HTL), and B-cell epitopes from the B2L, F1L, and 080 protein of ORFV were selected and linked by short connectors to construct a multi-epitope subunit vaccine. Immunogenicity was enhanced by adding an adjuvant β-defensin to the N-terminal of the vaccine using the EAAAK linker. The vaccine exhibited a significant degree of antigenicity and solubility, without allergenicity or toxicity. The 3D formation of the vaccine was subsequently anticipated, improved, and verified. The optimized model exhibited a lower Z-score of -4.33, indicating higher quality. Molecular docking results demonstrated that the vaccine strongly binds to TLR2 and TLR4. Molecular dynamics results indicated that the docked vaccine-TLR complexes were stable. Immune simulation analyses further confirmed that the vaccine can induce a marked increase in IgG and IgM antibody titers, and elevated levels of IFN-γ and IL-2. Finally, the optimized DNA sequence of the vaccine was cloned into the vector pET28a (+) for high expression in the E.coli expression system. Overall, the designed multi-epitope subunit vaccine is highly stable and can induce robust humoral and cellular immunity, making it a promising vaccine candidate against ORFV.

Pathogenicity and phylogenetic analysis of ovine contagious ecthyma virus isolated during a sheeppox outbreak in Morocco

Contagious ecthyma (CE), also known as ORF is a highly contagious zoonotic viral skin disease that affects humans, sheep, goats and other domesticated and wild animals. As reported here-in, the objective of this study was to investigate a suspected outbreak of both sheeppox and ORF diseases in a sheep herd during the winter of 2020 in Northwest Morocco. The affected sheep showed nodules and proliferative scabby skin lesions around the mouth and hairless area of the body. Samples of skin crust were collected for virus identification and isolation. A virus was isolated in Vero cells, lamb testis and heart cells and the cytopathic effect was characterized by cells aggregation, ballooning, and detachment. Initially, the suspensions of skin crust were positive for sheeppox virus (SPPV) by PCR. Subsequent testing of the isolated virus from skin crust of affected animals indicated that the virus was SPPV-negative and ORFV-positive by PCR. Furthermore, nucleotide sequences of the B2L aligned with reference ORFV isolates for genetic analysis. Phylogenetic analyses results confirmed that the isolated virus was ORFV and that the virus was closely related to ORFV strains isolated in Sudan and Malaysia. In conclusion, this study is the first reported detection of ORFV in Morocco, and therefore, poses as an imminent threat to the health of humans, domestic and wild animals.

Contagious ecthyma in Egypt: Clinical, virological and molecular explorations

Contagious Ecthyma (CE) is a highly contagious viral disease of sheep and goats with worldwide distribution. The present study aimed to provide a clinical description of contagious ecthyma in four sheep flocks and screen the possible genetic variation in the B2L gene of the detected isolates. Oral lesions were collected and inoculated into chorioallantoic membrane (CAM) of 11 days embryonated chicken eggs. Polymerase chain reaction and direct sequencing of the B2L gene was conducted. Infected sheep exhibited anorexia with a development of nodular lesions evolving in proliferative thick scabs around oral commissures. The inoculated CAM showed small-sized white pock lesions accompanied with thickening of CAM. The partial length of B2L gene (592 bp) was successfully amplified in samples collected from four flocks. The isolated strains belong to genotype I/I and I/II. Sequence and evolutionary analysis illustrate that B2L gene (ORF011) are highly conserved among Orf viruses isolated from different countries.

The whole genomic analysis of the Orf virus strains ORFV-SC and ORFV-SC1 from the Sichuan province and their weak pathological response in rabbits

The Orf virus (ORFV) is a member of the Parapoxvirus genus of the Poxviridae family and can cause contagious diseases in sheep, goats, and wild ungulates. In the present study, two ORFV isolates (ORFV-SC isolated from Sichuan province and ORFV-SC1 produced by 60 passages of ORFV-SC in cells) were sequenced and compared to multiple ORFVs. The two ORFV sequences had entire genome sizes of 14,0707 bp and 141,154 bp, respectively, containing 130 and 131 genes, with a G + C content of 63% for the ORFV-SC sequence and 63.9% for the ORFV-SC1 sequence. Alignment of ORFV-SC and ORFV-SC1 with five other ORFV isolates revealed that ORFV-SC, ORFV-SC1, and NA1/11 shared > 95% nucleotide identity with 109 genes. Five genes (ORF007, ORF20, ORF080, ORF112, ORF116) have low amino acids identity between ORFV-SC and ORFV-SC1. Mutations in amino acids result in changes in the secondary and tertiary structure of ORF007, ORF020, and ORF112 proteins. The phylogenetic tree based on the complete genome sequence and 37 single genes revealed that the two ORFV isolates originated from sheep. Finally, animal experiments demonstrated that ORFV-SC1 is less harmful to rabbits than ORFV-SC. The exploration of two full-length viral genome sequences provides valuable information in ORFV biology and epidemiology research. Furthermore, ORFV-SC1 demonstrated an acceptable safety profile following animal vaccination, indicating its potential as a live ORFV vaccine.

Epidemiology, clinical features, and molecular detection of orf virus in Haryana (India) and its adjoining areas

Orf is an acute, highly contagious, and economically important viral disease of small ruminants. In this study, six orf suspected outbreaks among goats and sheep were investigated from Haryana state and adjoining areas of Rajasthan state during the year 2021. The disease was diagnosed on the basis of clinical signs and molecular identification. The causative agent of the disease, orf virus (ORFV), was confirmed using polymerase chain reaction (PCR) targeting immunodominant envelope antigen (B2L) gene and confirmed by sequencing. The morbidity in goats ranged from 8.75 to 100%, whereas in sheep, it ranged from 0 to 8%. The higher mortality was observed among flocks with mixed infections of orf and peste des petits (PPR) or orf and haemonchosis as compared to other outbreaks. The phylogenetic analysis of sequenced PCR products clustered the current study strains in the same clad with Indian as well as strains from other countries with nucleotide identity more than 99%, signifying a close genetic relationship. The study highlighted the circulation of strains of a single cluster among sheep and goats in Haryana and adjoining areas. Prompt diagnosis of the disease is highly important for facilitating the implementation of control measures to minimize the losses suffered by small and marginal farmers in this region. Further detailed studies are required to delineate the molecular details of ORFV for better understanding the dynamics and molecular epidemiology of strains circulating in the country and for designing the effective vaccines against the disease which are currently lacking in the country.

Molecular phylogenetic analysis of bovine papular stomatitis viruses detected in Saga, Japan

In this study, we performed a molecular phylogenetic analysis of six bovine papular stomatitis virus (BPSV) field strains detected from Japanese beef calves kept on a farm in Saga prefecture, a southwest part of Japan, from 2017 to 2020. The phylogenetic analysis based on a partial B2L gene (554-nt) showed that these field strains were divided into two lineages, a lineage (A-lineage) constructed by a Saga strain and strains obtained from various regions of Japan and the world, and other lineage (B-lineage) constructed by five Saga strains and strains obtained from France, USA and Iwate prefecture (a north part of Japan). Furthermore, a Saga field strain named BPSV_SAGAbv2 and strains obtained from USA and Iwate prefecture belonged to a sub-lineage blanched from B-lineage. This is the first report elucidating molecular epidemiological characters of field BPSVs obtained from Saga prefecture. The existence of the multiple lineages was thought to be related to a history of calf introduction from various regions of Japan into Saga prefecture.

Molecular characterization and phylogenetic analysis of orf virus isolated from goats in Sokoto metropolis, Nigeria

Aim:

The aim of this study was to molecularly characterize orf virus isolated from clinical infections in goats in Sokoto metropolis.

Materials & methods:

Embryonated chicken eggs were used to isolate orf virus according to the established protocol. Viral DNA was extracted and full coding region of B2L gene was amplified by polymerase chain reaction, sequenced and blasted for identification and phylogenetically analyzed.

Results and discussion:

The B2L gene sequences of the isolate showed slight variability (96–98.7%) with the reference sequences as it clustered within the same clade with Korean, Zambian and Ethiopian strains, signifying a close genetic relationship. Unique amino acid substitutions were noted. This is the first genetic characterization of B2L gene of orf virus circulating in Nigeria.

Conclusion:

This study has provided in sight into the genetic diversity of orf virus in the study area.

Contagious ecthyma has for long been affecting the goat and sheep population in Nigeria leading to huge economic losses to livestock farmers through death and poor market value of the affected animals. Recently, increased death due to this disease has been reported in north-central Nigeria, but the nature of the disease-causing agent has not been reported yet. It is the aim of this study to understand the nature of the virus causing the disease in goats in Sokoto using molecular biology techniques so as to facilitate better vaccine design for the effective control of the disease in Nigeria.

Laboratory Diagnosis of a NZ7-like Orf Virus Infection and Pathogen Genetic Characterization, Particularly in the VEGF Gene

Orf is a widespread contagious epithelial viral disease found particularly in most sheep breeding countries in the world. Recently, an orf virus (ORFV) strain OV-HLJ05 was isolated from an outbreak in northeast China. Three genes of interest including ORFV011 (B2L), ORFV059 (F1L), and ORFV132 (VEGF) of ORFV, were recruited to identify and genetically characterize this newly isolated virus. Amino acid (aa) sequence compared with the ORFV references listed in GenBank, both B2L and F1L of OV-HLJ05 showed less microheterogeneity from their references. In contrast, the VEGF gene was included in the NZ7-VEGF like group as previously considered by Mercer in 2002. Unexpectedly, further multiple VEGF matches were made, using 34 published sequences from China and India, resulting in 27 strains of the NZ7 members. Based on Karki's report in 2020, NZ7-VEGF like viruses are emerging more and more frequently in these two countries, damaging the Asian sheep industry. Obvious heterogeneity with the NZ2, insertion of two oligopeptides TATI(L)QVVVAI(L) and SSSS(S) motif were found in the NZ7-like VEGF protein. These VEGFs are divided mainly into two types and a significant increase in the number of hydrogen bonds within the NZ7-like VEGF dimers was observed. The NZ7-like ORFV apparently favors the goat as a host and an emphasis on this in future epidemiological and pathological studies should be considered, focusing on the NZ7-like virus.

Lumpy skin disease (LSD) outbreaks in cattle in Odisha state, India in August 2019: Epidemiological features and molecular studies

Lumpy skin disease (LSD) caused by lumpy skin disease virus (LSDV) inflicts significant economic losses in cattle production with impact on livelihoods of smallholders. This study reports the first occurrence of LSD in cattle in India and analyses epidemiological and genetic characterization data from LSD outbreaks in five districts of Odisha state in August 2019. In all, 182 of 2,539 cattle were affected with an apparent morbidity rate of 7.1% and no mortality. Out of 102 samples from 60 LSD suspected and 17 asymptomatic in-contact cattle tested, 29.87% cattle were positive by capripoxvirus generic PCR and 37.66% were positive by LSDV real-time PCR. All the in-contact cattle tested were negative for LSDV. Among affected cattle, LSDV genome was detected more in scabs (79.16%) than blood (31.81%) and frozen bull semen (20.45%). Differential diagnosis by PCR was negative for pseudo-LSD, buffalopox, cowpox, pseudo-cowpox and bovine papular stomatitis. Five selected PCR and real-time PCR-positive LSDV DNA were sequenced in three genomic regions, P32 (LSDV074), F (LSDV117) and RPO30 (LSDV036). Phylogenetic analysis based on partial P32 and F gene sequences and complete RPO30 gene sequences showed that all the five Indian LSDV strains were identical and clustered with other field strains of LSDV circulating globally. However, the F and RPO30 gene sequence analyses revealed that Indian LSDV strains are genetically closer to the South African NI2490/KSGP-like strains than the strains detected in Europe, which was rather surprising. The present study established the existence of LSDV in India and involvement of LSDV field strains in the outbreaks. Additionally, we provided evidence of LSDV shedding in semen of naturally infected bulls. Further studies are required to determine the source of LSD introduction, extent of spread, modes of transmission and impact on dairy cattle production in India and effective control measures must be undertaken urgently.

Genetic Variability of 3'-Proximal Region of Genomes of Orf Viruses Isolated From Sheep and Wild Japanese Serows (Capricornis crispus) in Japan

Orf virus is a prototype species of the genus Parapoxvirus, subfamily Chordopoxvirinae, family Poxviridae. Japanese orf viruses, infecting sheep and wild Japanese serows (Capricornis crispus), have been considered to be genetically closely related based on the sequence identities of the open reading frames (ORFs) 11, 20, and 132 in their genomes. However, since the genome size of orf viruses is about 140 kbp long, genetic variation among Japanese orf viruses remains unclear. In this study, we analyzed the sequences of ORFs 117, 119, 125, and 127 located in the 3′-proximal region of the viral genome using two strains from sheep and three strains from Japanese serows isolated from 1970 to 2007, and compared them with the corresponding sequences of reference orf viruses from other countries. Sequence analysis revealed that ORFs 125 and 127, which encode the inhibitor of apoptosis and viral interleukin (IL)-10, respectively, were highly conserved among the five Japanese orf viruses. However, high genetic variability with deletions or duplications was observed in ORFs 117 and 119, which encode granulocyte macrophage colony-stimulating factor and IL-2 inhibition factor (GIF), and inducer of cell apoptosis, respectively, in one strain from sheep and two strains from Japanese serows. Our results suggest that genetic variability exists in Japanese orf viruses even in the same host species. This is the first report of genetic variability of orf viruses in Japan.

Orf Virus VIR Antagonizes p53-Mediated Antiviral Effects to Facilitate Viral Replication

As a zoonotic disease, ovine contagious pustular dermatitis (Orf) is a serious threat to sheep as well as humans. Orf virus (ORFV) interferon resistance protein (VIR) is the principal virulence protein that encodes a dsRNA-binding protein to inhibit host antiviral response. p53 is one of the key proteins of the host antiviral innate immunity. It not only enhances type I interferon secretion but also induces apoptosis in infected cells, and plays a crucial role in the immune response against various viral infections. However, it remains to be elucidated what role p53 plays in ORFV replication and whether ORFV's own protein VIR regulates p53 expression to promote self-replication. In this study, we showed that p53 has an antiviral effect on ORFV and can inhibit ORFV replication. In addition, ORFV nonstructural protein VIR interacts with p53 and degrades p53, which inhibits p53-mediated positive regulation of downstream antiviral genes. This study provides new insight into the immune evasion mediated by ORFV and identifies VIR as an antagonistic factor for ORFV to evade the antiviral response.

Identification of strain diversity and phylogenetic analysis based on two major essential proteins of Orf viruses isolated from several clinical cases reported in Malaysia

There is a little information on the characterization of Orf virus strains that are endemic in Malaysia. The relationship between the severity of disease and the molecular genetic profile of Orf virus strains has not been fully elucidated. This study documented the first confirmed report of contagious ecthyma causing by Orf virus in goats from a selected state of eastern peninsular Malaysia. The disease causes significant debilitation due to the inability of affected animals to suckle which brings a great economic loss to the farmers. A total of 504 animals were examined individually to recognize the affected animals with Orf lesion. Skin scrapping was used to collect the scab material from the infected animals. The presence of Orf virus was confirmed by combination of methods including virus isolation on vero cells, identification by Transmission Electron Microscopy (TEM) and molecular technique using PCR and Sanger sequencing. The results showed the successful isolation of four Orf virus strains with a typical cytopathic effects on the cultured vero cells line. The morphology was confirmed to be Orf virus with a distinctive ovoid and criss cross structure. The phylogenetic analysis revealed that these isolated strains were closely related to each other and to other previously isolated Malaysian orf viruses. In addition these Orf virus strains were closely related to Orf viruses from China and India. This study provides more valuable insight in terms of genotype of Orf virus circulating in Malaysia.

Molecular characterization of Orf virus isolates from Kodai hills, Tamil Nadu, India

Aim:

The present study was carried out to find out the causative agent of exanthematous skin lesions in sheep maintained by Southern Regional Research Centre, Mannavanur, Kodai hills, Tamil Nadu.

Materials and Methods:

Polymerase chain reaction (PCR) with Orf virus (ORFV) B2L gene-specific primers was carried out by employing the total genomic DNA isolated from the scabs as the template. The ORFV isolates from Kodai hills were characterized by the use of bioinformatics tools.

Results:

The amino acid identity of ORFV isolate 1 from Kodai hills is having 98.14%, 96.29%, and 83.59% identity with reference strains of ORFV, Pseudocowpox virus, and bovine papular stomatitis virus, respectively. Phylogenetic analysis revealed that ORFV isolates from Kodai hills clustered with the other ORFV isolates from different geographical areas of India.

Conclusion:

The etiological agent of exanthematous skin lesion among sheep of Kodai hills is ORFV.

Poxviral E3L ortholog (Viral Interferon resistance gene) of orf viruses of sheep and goats indicates species-specific clustering with heterogeneity among parapoxviruses

Orf is a contagious disease posing a serious threat to animal and human health. E3L is one of the evolutionarily acquired immunomodulatory proteins present in orf virus (ORFV) and is responsible for conferring resistance to interferons among poxviruses. Genetic analysis of ORFV isolates of different geographical regions including Indian subcontinent targeting viral interferon resistance (VIR) gene (a homolog of vaccinia virus E3L gene) revealed a high percentage of identity among themselves and other ORFV isolates at both nt and aa levels as compared to low identity among parapoxviruses (PPVs). Phylogenetic analysis showed species-specific clustering among PPVs along with sub-clusters based on host species of origin among ORFVs infecting sheep and goats. Conserved amino acids in N-terminal Z-DNA binding domain and C-terminal ds RNA binding domain of VIR proteins of PPVs corresponding to ORFV VIR positions namely N37, Y41, P57, and W59 (necessary for Z-DNA binding) and E116, F127, F141, and K160 (necessary for dsRNA binding) were found. Further, the predicted protein characteristics and homology model of VIR protein of ORFV showed high structural conservation among poxviruses. This study on E3L genetic analysis of ORFV isolates may provide a better understanding of the molecular epidemiology of circulating strains in India and neighboring countries. Also, E3L deleted or mutated ORFV may be an as vaccine candidate and/or compounds blocking E3L may prove as an effective method for treating broad spectrum poxviral infections, suggesting a wider application in control of poxvirus infections.

Comparison of the sensitivity of three cell cultures to ORFV

Background

Contagious ecthyma (CE) appears in the countries and regions containing goat and sheep farms, and it is considered a global epidemic. CE not only severely endangers the healthy development of the sheep and goat industries but also threatens human health. For viral infectious diseases, fast and effective isolation and culture of the pathogen is critical for CE diagnosis, and for disease prevention and control. Therefore, the sensitivity of bovine Sertoli cells to ORFV was estimate in this study.

Results

The sensitivities of bovine Sertoli cells, primary neonatal bovine testicular cells, and Madin-Darby bovine kidney (MDBK) cell line to ORFV were compared. Our results showed that the isolated bovine Sertoli cells were sensitive to inoculated ORFV, and viral titers were approximately 1 log higher than those in primary neonatal bovine testicular cells and in MDBK cell lines.

Conclusion

Appropriately sensitive cells for the highly efficient isolation and culture of the ORFV were obtained. Culture of ORFV using the Sertoli cells showed good consistency and stability and also avoided the risk of other pathogens presenting during viral culture using a primary cell line. In addition, using these passaged bovine Sertoli cells to proliferate ORFV may simplify the CE diagnosis process, thereby reducing detection time and cost. Hence, this test has important practical significance for the diagnosis of CE and the research on the pathogenic mechanism of ORFV.

Detection and phylogenetic analysis of Orf virus in Kashmir Himalayas

Orf virus (ORFV) is a zoonotic pathogen that primarily infects sheep and goats, and is responsible for significant economic losses. ORFV is endemic in all the major sheep and goat rearing areas of the world including Indian subcontinent. However, the nature of ORFV circulating among sheep and goat in Kashmir Himalayas has not yet been characterized. In the present study, we describe natural outbreaks of ORFV in sheep and goats of Kashmir Himalayas. We detected the presence of ORFV in the scab lesion by PCR amplification of the major envelope protein (B2L) gene. We sequenced the virus interferon resistance (VIR) gene and determined their phylogenetic relationship with that of the published reference sequences. Phylogenetic analysis based on VIR gene revealed that the ORFV isolates from Kashmir Himalayas separated into main two clusters. The sheep isolates showed genetic homology with the sheep strains reported from Greece and Italy, whereas the goat-specific strain show homology with the goat strains reported from China. This study demonstrates the presence of ORFV infection in sheep and goats, and report first phylogenetic analysis of the ORFV strains prevalent in the Kashmir Himalayas.

Phylogenetic Analysis of ORF Viruses From Five Contagious Ecthyma Outbreaks in Argentinian Goats

Orf virus (ORFV) is the etiological agent of Contagious Ecthyma (CE) disease that mainly affects sheep, goats, wild ruminants, and humans with a worldwide distribution. To date, only two strains from Argentinian sheep have been characterized at the molecular level and there is little information on ORFV strains circulating in Argentina. Here we describe and analyze five outbreaks of CE in goats in three geographic regions of the country: Northwest, Center, and Southwest. The phylogenetic analysis based on four molecular markers of ORFV (orf011 partial sequence and orf020, orf109, and orf127 complete sequence genes) revealed that there are different strains circulating in Argentina and pointed out the importance of knowing the health status of animals traded between farms.

Phylogenetic analysis of Orf virus associated with contagious ecthyma (orf) outbreak in Tellicherry goats (Capra hircus)

Orf virus (ORFV) is a member of genus Parapoxvirus that causes contagious ecthyma in goats. A pox-like disease was investigated in Tellicherry goats (31 female) maintained at a semi-organized farm. History revealed recent introduction of Tellicherry goats for breeding purpose and housing of the new entrants in to a farm already having a mild form of pox-like disease. Newly introduced and stressed Tellicherry goats developed severe form of infection with 100% morbidity. Affected goats showed lesions around lips (100%), commissure (53%) and oral cavity (65%); exanthematic dermatitis was evident in 94% of the affected goats followed by ulceration (47%) and nodular lesions (24%). Scab samples were collected from affected goats to confirm the clinical diagnosis. Genus Parapoxvirus was confirmed by the amplification of specific 594 bp and 235 bp amplicons. Further, Orf virus specific amplicon of size 1,206 bp was also amplified for the confirmation. Sequence analysis of PCR amplicons showed close resemblance of the outbreak strain with reported Indian Orf virus isolates. Based on the homology of the outer envelope protein B2L gene sequence of Orf virus, the source of infection to the Tellicherry goats was traced to the local goat. Although Orf virus is zoonotic; however, no occupational transmission was noticed in the present outbreak.

Genetic diversity of Orf virus isolated from sheep in Uruguay

Orf virus (ORFV) is the etiological agent of contagious ecthyma, a disease widely spread in the world that occasionally causes zoonotic infections. This work is the first molecular characterization of ORFV in Uruguay, where we analyzed twenty-one sheep samples, eighteen of which were recovered from thirteen ORFV outbreaks that occurred during 2004 to 2011 as well as three strains from a national vaccine. Phylogenetic analysis and the derived amino acid sequences from the B2L gene suggest that the Uruguayan virus do not form a unique cluster, with most of them displaying similarities with worldwide ORFV isolates as well as our vaccine strains.

Molecular identification and investigations of contagious ecthyma (Orf virus) in small ruminants, North west Ethiopia

Background

Orf virus, the prototype of parapoxvirus, is the main causative agent of contagious ecthyma. Little is known about the status of the disease in Ethiopia and this study was aimed at determining its status using PCR as a confirmatory tool.

Methods

a total of 400 randomly selected sheep and goat was screened for the identification of the virus using amplification of B2L gene and transfection of mammalian cells (VERO cells).

Results

Out of 400 animals screened for infection of the virus, 48 animals were found positive to PCR and revealed an overall incidence of 12%. Different epidemiological parameters were considered to look at the association with incidence of the disease and of which, only species of the animal(sheep), non-vaccinated and non-treated animals, nursing animals, poor body condition animals, extensively managed animals, animals having mouth lesion, and study areas having outbreak history showed higher prevalence. A univariate logistic regression analysis showed statistically significant difference in all variables (P < 0.05). Whereas, age and sex of animals showed no significant difference (P < 0.05).

Conclusion

The result of the present finding showed high incidence of Orf virus in the region as confirmed through PCR.

First isolation and genetic characterization of pseudocowpox virus from cattle in Japan

Background

Pseudocowpox virus (PCPV) infects cattle worldwide with zoonotic potential but has not been isolated in Japan. Thus, the epidemiological status of PCPV infection in cattle is undetermined.

Results

In May 2016, a cattle in a farm in Yamaguchi Prefecture showed white vesicles and hyperemia in the mucosa under the tongue surface, but not on the teats and coronary cushions. A parapoxvirus was isolated from the oral lesion swab and was genetically characterized based on the full-length sequence of B2L gene encoding viral envelope. Phylogenetic analysis showed that the isolated virus was classified into PCPV.

Conclusion

This case indicates its potential spread in Japan. This is the first report of isolation of PCPV in Japan.

Electronic supplementary material

The online version of this article (10.1186/s12985-017-0840-3) contains supplementary material, which is available to authorized users.

The whole genomic analysis of orf virus strain HN3/12 isolated from Henan province, central China

Background

The Orf virus (ORFV) is the causative agent of orf, a globally-occurring, acute, pustular, contagious disease affecting sheep, goats and humans with a worldwide distribution. Currently, the genomic analysis of four ORFV strains from the Fujian province in southern China and a NA1/11 strain isolated from the Jilin province in northeast China have been reported. However, little is known about the genomic information of ORFV strains from central China.

Results

From a recent outbreak in a sheep herd in the Henan province of central China, a novel ORFV strain (HN3/12) was isolated and cultured in ovine fetal turbinate (OFTu) cells. The strain was identified as HN3/12 and verified by PCR based on the DNA sequences of 011 and 059 genes. The whole genomic sequence of this isolate was determined by Next Generation Sequencing technology. To determine the genetic characteristics of the HN3/12 strain, phylogenetic analysis of the 011 and 059 genes and amino acid sequence alignment of the HN3/12 strain were performed and compared with reference parapoxvirus strains.

Conclusions

The HN3/12 genome is 136,643 bp in length, contains 63.67% G + C and encodes 132 putative genes. Phylogenetic analysis of the 011 and 059 nucleotide sequences showed that this viral strain was similar to the NA1/11 isolate. The homology analysis indicates that HN3/12 has 93% to 98% identity with published ORFV strains at amino acid level. When open reading frames (ORFs) were aligned among the HN3/12 and four Fujian ORFV strains, most of them have identities greater than 90% and only a few less than 60%. The availability of the whole genomic sequence of HN3/12 aids in our understanding of, and provides new insights into, the genetic diversity of ORFV.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-017-1178-1) contains supplementary material, which is available to authorized users.

Identification and phylogenetic analysis of contagious ecthyma virus from camels (<i>Camelus dromedarius</i>) in Iran

Contagious ecthyma is a highly contagious disease affecting domestic and wild ruminants such as sheep, goats and camels. The identification and characterisation of a parapoxvirus (PPV) infecting camels is described here. The virus was detected in dromedary camels (Camelus dromedarius) from Kerman and Shiraz in Iran. PPV-specific amplification by polymerase chain reaction (PCR) further confirmed that the disease was associated with PPV infection. Phylogenetic analysis of ORF011 (B2L) gene sequences showed 99.79% and 82.13% similarity of the PPV identified in this study with the Jodhpur isolate and the bovine papular stomatitis virus (BPSV) isolates (CE41), respectively. Moreover, phylogenetic analysis of the ORF045 gene indicated that the Shiraz sample was in all probability closely related to VR634 and to F00.120R and PCPV776. In conclusion, the results suggest that camel PPV (CPPV) is a likely cause of contagious ecthyma in dromedary camels in Iran.

Functional characterization of recombinant major envelope protein (rB2L) of orf virus

Orf, or contagious ecthyma, a highly contagious transboundary disease of sheep and goats, is caused by a double-stranded DNA virus (ORFV) belonging to the genus Parapoxvirus of the family Poxviridae. The ORFV genome encodes the major envelope proteins B2L and F1L, which have been found to be highly immunogenic and have multiple functional characteristics. In order to investigate the functional properties of the B2L protein, in this study, the B2L gene of ORFV strain 59/05, encoding recombinant mature B2L (aa ₁M-D₃₃₄), was produced as a fusion protein in Escherichia coli. The functional characteristics of purified rB2L fusion protein (~60 kDa) were evaluated in vivo and in vitro, showing that this protein had lipase and immunomodulatory activities. Immunization trials involving laboratory animals (mice, rabbits and guinea pigs) using either constant or graded doses of rB2L fusion protein with or without adjuvants (FCA, alum) as well as co-administration with candidate rErns-Ag protein of classical swine fever virus (CSFV) indicated that the rB2L protein is immunogenic and has immunomodulatory properties. This study shows the potential utility of the rB2L protein as a safe and novel adjuvant in veterinary vaccine formulations.

Unique Presentation of Orf Virus Infection in a Thermal-Burn Patient After Receiving an Autologous Skin Graft

We describe a burn patient who developed skin lesions on her skin-graft harvest and skin-graft recipient (burn) sites. Orf virus infection was confirmed by a combination of diagnostic assays, including molecular tests, immunohistochemical analysis, pathologic analysis, and electron microscopy. DNA sequence analysis grouped this orf virus isolate among isolates from India. Although no definitive source of infection was determined from this case, this is the first reported case of orf virus infection in a skin graft harvest. Skin graft recipients with exposures to animals may be at risk for this viral infection.

Development of a lateral flow immunochromatographic assay for the rapid diagnosis of Orf virus infections

A rapid and simple lateral-flow immunochromatographic assay (LFIA) was developed for the specific detection of Orf virus (ORFV) using two distinct monoclonal antibodies (MAbs: 5A5 and 6F2) against the ORFV ORF011 protein. The MAb 5A5 was conjugated with colloidal gold, and the MAb 6F2 and goat anti-mouse IgG were sprayed onto a nitrocellulose membrane in strips at positions designated test (T) and control (C), respectively. The results showed that samples of ORFV complexed with colloidal gold-conjugated MAb 5A5, were captured by MAb 6F2 at the T line resulting in the appearance of a purple band. When samples did not contain ORFV or when they contained a quantity of ORFV below the detection limit of the test, only the C line was visible. The analysis of sensitivity of the test demonstrated that the lowest detected quantity of ORFV was 2.03×10(3.0) TCID50/ml. Storage at room temperature for 6 months did not result in the loss of performance of the LFIA test. Using loop-mediated isothermal amplification (LAMP) as a reference test, the relative specificity and sensitivity of the LFIA test were determined to be 100% and 92.1%, respectively. Based on these results, the LFIA test developed may be a suitable tool for rapid on-site testing for ORFV infection.

Molecular characterization of orf virus from sheep and goats in Ethiopia, 2008-2013

Background

Orf is a contagious disease of sheep, goats and wild ungulates caused by orf virus (ORFV) a member of the genus Parapoxvirus, Poxviridae family. Although orf is endemic in Ethiopia, little attention has been given so far as it is not a notifiable disease by the World Organization for Animal Health. In this work, we have investigated orf outbreaks representing five different geographical locations of Ethiopia, in Amba Giorgis, Gondar zuria, Adet, Debre zeit and Adami Tulu, between 2008 and 2013.

Results

The viral isolation and the sequence analysis of the A32L and the B2L genes of eighteen representative isolates confirmed that sampled animals were infected by ORFVs.

The phylogenetic study and the comparative analysis of the deduced amino acid profile suggests that there were two main clusters of ORFV isolates which were responsible for the investigated outbreaks. Additionally the analysis of these two genes showed limited variability to ORFVs encountered elsewhere. This is the first report on the genetic characterization of the ORFV isolates from sheep and goats in Ethiopia.

Conclusion

The molecular characterization of Ethiopian ORFV isolates highlighted the circulation of two main clusters causing orf disease in sheep and goats. The use of laboratory based methods and a constant monitoring of Ethiopian ORFV isolates is needed to better understand the dynamic of ORFV circulating in the country and facilitate the implementation of control measures.

Electronic supplementary material

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Isolation and phylogenetic analysis of caprine Orf virus in Malaysia

Orf virus is a DNA virus that causes contiguous ecthyma in goat and sheep. Infection of animals with this virus cause high mortality in young animals resulting in huge economic losses. In this study, we investigated an outbreak of Orf in a goat farm in Malaysia. Samples were collected from infected animals and viral isolation was done using both LT and MDCK cell lines. Molecular detection was done by conventional PCR for specific primers; B2L and F1L genes and phylogenetic analysis was done on the sequence data obtained. Cytopathic effects (CPE) were observed in both cell lines after 3 days of inoculation and were 50 % by the sixth day. PCR showed positive bands for both B2L and F1L genes and phylogenetic analysis showed that the Malaysian strain had close homology to the Chinese and Indian Orf virus isolates. This study gives more insight into the existing Orf viral strains in Malaysia and their relationship with other strains globally.

Phylogenetic analysis of three orf virus strains isolated from different districts in Shandong Province, East China

Orf virus (ORFV) is the causative agent of contagious ecthyma, which is a zoonotic disease that affects sheep, goats, wild small ruminants and humans. Shandong Province in East China is one of the main producing areas in China for sheep and goats. Here, we conducted epidemiological surveys in different areas in this Province, isolated three orf virus strains, SDLC, SDTA and SDJN, from goat flocks and then analyzed the genetic evolution of these strains. The ORFV011, ORFV059, ORFV109, ORFV110 and ORFV127 genes of these three strains were amplified, sequenced and analyzed. Phylogenetic analysis showed that ORFV011 of the SDLC and SDTA strains cluster together with the Gansu, Liaoning, Shanxi, Nantou, Hoping and FJ-YX strains, while SDJN clusters with the FJ-GS and FJ-GO strains. ORFV059 of the SDLC and SDTA strains cluster together with the FJ-YX strain, while SDJN clusters with the FJ-GS and FJ-GO strains. ORFV059 and ORFV127 of these three strains were similar to those of the OV-SA00 strain. The results suggested that SDLC, SDTA and SDJN originated from Fujian Province and formed a complex group of viruses in Shandong Province. As the role of ORFV127 gene responsible for the immune evasion of ORFV, the pathogenesis of these three virus strains may similar to that of OV-SA00. These three strains first isolated in Shandong Province are novel ORFV strains, and the data reported here will be helpful for further research about ORFV and its comprehensive prevention and control.

Phylogenetic analysis of eight sudanese camel contagious ecthyma viruses based on B2L gene sequence

BACKGROUND

Camel contagious ecthyma (CCE) is an important viral disease of camelids caused by a poxvirus of the genus parapoxvirus (PPV) of the family Poxviridae. The disease has been reported in west and east of the Sudan causing economical losses. However, the PPVs that cause the disease in camels of the Sudan have not yet subjected to genetic characterization. At present, the PPV that cause CCE cannot be properly classified because only few isolates that have been genetically analyzed.

METHODS AND RESULTS

PCR was used to amplify the B2L gene of the PPV directly from clinical specimens collected from dromedary camels affected with contagious ecthyma in the Sudan between 1993 and 2013. PCR products were sequenced and subjected to genetic analysis. The results provided evidence for close relationships and genetic variation of the camel PPV (CPPV) represented by the circulation of both Pseudocowpox virus (PCPV) and Orf virus (ORFV) strains among dromedary camels in the Sudan. Based on the B2L gene sequence the available CPPV isolates can be divided into two genetic clades or lineages; the Asian lineage represented by isolates from Saudi Arabia, Bahrain and India and the African lineage comprising isolates from the Sudan.

CONCLUSION

The camel parapoxvirus is genetically diverse involving predominantly viruses close to PCPV in addition to ORFVs, and can be divided into two genetically distant lineages. Based on sequences of the B2L gene it is not possible to suggest that the viruses that cause CCE form a monophylogenetic group or species within the PPV phylogeny.

Isolation and molecular characterization of Orf virus from natural outbreaks in goats of Assam

Outbreaks of contagious ecthyma (caused by a Parapox virus) in goats were investigated in 6 districts of Assam, a north eastern state of India. Diagnosis of the disease was carried out employing both standard virological as well as molecular methods. Four representative isolates from different places were selected for phylogenetic analysis. The major envelop protein (B2L) of Orf virus was targeted for molecular analysis. The sequencing and phylogenetic analysis of the selected sequences at nucleotide level revealed that the Orf virus isolates were closely related to each other (97.6-100 %) and showed highest similarity to the Orf virus isolate 82/04 (98.4 %), reported from Shahjahanpur, India. The data will provide an insight in transmission of the virus from northern to North eastern part of the country.

Suppression of influenza virus infection by the orf virus isolated in Taiwan

Orf virus (ORFV), a member of parapoxvirus, is an enveloped virus with genome of double-stranded DNA. ORFV causes contagious pustular dermatitis or contagious ecthyma in sheep and goats worldwide. In general, detection of viral DNA and observing ORFV virion in tissues of afflicted animals are two methods commonly used for diagnosis of orf infection; however, isolation of the ORFV in cell culture using virus-containing tissue as inoculum is known to be difficult. In this work, the ORFV (Hoping strain) isolated in central Taiwan was successfully grown in cell culture. We further examined the biochemical characteristic of our isolate, including viral genotyping, viral mRNA and protein expression. By electron microscopy, one unique form of viral particle from ORFV infected cellular lysate was demonstrated in the negative-stained field. Moreover, immunomodulating and anti-influenza virus properties of this ORFV were investigated. ORFV stimulated human monocytes (THP-1) secreting proinflammatory cytokines IL-8 and TNF-α. And, pre-treatment of ORFV-infected cell medium prevents A549 cells from subsequent type A influenza virus (IAV) infection. Similarly, mice infected with ORFV via both intramuscular and subcutaneous routes at two days prior to IAV infection significantly decreased the replication of IAV. In summary, the results of a current study indicated our Hoping strain harbors the immune modulator property; with such a bio-adjuvanticity, we further proved that pre-exposure of ORFV protects animals from subsequent IAV infection.

Development and comparative evaluation of loop mediated isothermal amplification (LAMP) assay for simple visual detection of orf virus in sheep and goats

A loop-mediated isothermal amplification (LAMP) assay targeting DNA Pol gene was optimized and evaluated for the rapid detection of orf virus in clinical samples. The LAMP assay was found to be specific and sensitive. The detection rate of LAMP (89.3%) was better than PCR (67.9%) and comparable to real-time PCR (91.1%) in clinical samples by gel electrophoresis and visual detection methods. This LAMP assay is simple and does not rely upon any special equipment and could be employed in clinical diagnosis and epidemiological survey of orf infection.

Identification, phylogenetic evolutionary analysis of GDQY orf virus isolated from Qingyuan City, Guangdong Province, southern China

Infection with the orf virus (ORFV) leads to contagious ecthyma, also called contagious pustular dermatitis, which usually affects sheep, goats and other small ruminants. It has a great distribution throughout the world and has also been reported to infect humans. Though many strains have been isolated from differing parts of mainland China, rarely has any strain been reported from the southern provinces of China. We studied a case of orf virus infection that occurred at Qingyuan City, Guangdong Province in southern China. An orf virus strain, GDQY, was successfully isolated and identified through cell culture techniques and transmission electron microscopy. Complete genes of ORFV011, ORFV059, ORFV106 and ORFV107 were amplified for the sequence analysis based on their nucleotide or amino acid level. In order to discuss the genetic variation, precise sequences were used to compare to other reference strains isolated from different districts or countries. Phylogenetic trees based on those strains were built up and evolutionary distances were calculated based on the alignment of their complete sequences. The typical structure of the orf virus was observed in cell-culture suspensions inoculated with GDQY, and the full-length of four genes was amplified and sequenced. Phylogenetic analysis indicated that GDQY is homologous to FJ-DS and CQ/WZ on ORFV011 nucleotides. ORFV059 may be more variable than ORFV011 based on the comparison between GDQY and other isolates. Genetic studies of ORFV106 and 107 are reported for the first time in the presented study.

Human infection with ORF virus from goats in China, 2012

Orf virus, which belongs to the Parapoxvirus genus, induces a zoonotic infectious disease characterized by acute, highly vascularized cutaneous pustular lesions in sheep and goats. A number of Orf outbreaks have been reported in sheep and goats in recent years, but no reports have described an Orf virus strain from humans in China. In this study, we diagnosed Orf virus infection in two people, a mother and son, in the Gansu province of China. The human Orf virus was isolated and its phylogenetic characterization was analyzed based on a complete B2L gene. The results are useful for developing prospective programs to control Orf virus infections in both goats and humans.

TaqMan based real-time duplex PCR for simultaneous detection and quantitation of capripox and orf virus genomes in clinical samples

A rapid and sensitive TaqMan based real-time duplex PCR (drt-PCR) assay for simultaneous detection, differentiation and quantitation of Capripoxvirus (CaPV) and Orf virus (ORFV) DNA, was optimized targeting the highly conserved DNA polymerase genes of these virus genomes. Two pairs of oligonucleotide primers and two hybridization probes labeled with Cy5/BHQ1 and Hex/BHQ1 for CaPV and ORFV, respectively, were used in the drt-PCR assay. The assay was found to be specific only to targeted viruses and did not react with buffalopox virus (BPXV), camelpox virus (CMLV) (Orthopoxviruses) and cDNA of Peste des petits ruminants virus and bluetongue virus, the other common viruses of sheep and goats. The detection limit of the assay was 20 copies for each of the standard plasmid and 35fg of viral genomic DNA for CaPV and ORFV, respectively, in a single and mixed virus population. Both intra-(0.49-4.6% and 0.7-3.7%) and inter-(0.6-2.35% and 0.27-2.1%) assay variations of drt-PCR for CaPV and ORFV DNA were within the acceptable limits, implying high reproducibility and repeatability of the assay. Further, the diagnostic specificity and the sensitivity of the assay was assessed using known virus isolates of sheeppox virus (SPPV), goatpox virus (GTPV) and ORFV and the clinical specimens from sheep and goats. The developed drt-PCR assay was able to detect, differentiate, quantify simultaneously and also to identity mixed infections of CaPV and ORFV in sheep and goats.

Comparative and retrospective molecular analysis of Parapoxvirus (PPV) isolates

Species members of the genus Parapoxvirus (PPV) within the family Poxviridae cause contagious pustular dermatitis in small ruminants (Orf virus, ORFV) and mostly mild localized inflammation in cattle (bovine papular stomatitis virus, BPSV and pseudocowpox virus, PCPV). All PPVs are known to be zoonotic, leading to circumscribed skin lesions in humans, historically known as milker's nodules. Human PPV isolates are often ill defined concerning their allocation to an animal origin. Here we present a comparative molecular analysis of a unique collection of 21 historic and recent human and animal PPV cell culture isolates (and two PPV DNA samples). Cell culture PPV propagation was restricted to primary ruminant fibroblasts and was strictly kept at low passages to avoid genomic changes by in vitro influences. For molecular arrangement of the isolate DNAs and their attribution to established PPV species DNA fragments of the PPVs were generated by two different discriminating PCR protocols, targeting the major part of the open reading frame (ORF) 011 (B2L gene) and the complete ORF 032. Multiple sequence alignments and phylogenetic analysis of both genes resulted in affiliation to the known PPV species. The sequences from the ORF 032 allowed discrimination of the isolate DNAs at a higher resolution. Human PPV isolates could be clearly assigned to the PPV species belonging to the reported or assumed animal host of transmission. For the first time, a whole PPV genome sequence comparison of a human biopsy derived virus (B029) and its ovine counterpart (B015) originating from a defined Orf outbreak in Germany is provided, revealing their well conserved relationship. Thus human PPVs can be molecularly retraced to the PPV species indicating the animal of transmission. After transmission to the human host, molecular conservation of the animal's virus peculiarities indicative for a PPV species became evident.

Comparison and phylogenetic analysis based on the B2L gene of orf virus from goats and sheep in China during 2009-2011

As a zoonotic infectious disease, orf outbreaks have been reported in China in recent years. However, molecular epidemiology analysis has not been performed for Chinese orf virus (ORFV) strains. Here, we have identified 13 ORFVs from goats and sheep in China between 2009 and 2011. Thirty-four complete B2L sequences were used to construct a phylogenetic tree to elucidate the molecular epidemiology of ORFV in China. Nucleotide sequences of B2L genes of clinical samples and attenuated vaccine strains were aligned and compared. Three genotypes were found by molecular epidemiology analysis. Amino acid substitutions were dispersed among B2 polypeptides from wild and attenuated ORFV strains.

Heterogeneity among orf virus isolates from goats in Fujian Province, Southern China

Orf virus is a parapoxvirus that causes recurring contagious ecthyma or orf disease in goat, sheep and other wild and domestic ruminants. Infected animals show signs of pustular lesions on the mouth and muzzle and develop scabs over the lesions. Although the infection is usually cleared within 1–2 months, delayed growth and associated secondary infections could still impact the herds. Orf virus can also infect humans, causing lesions similar to the animals in pathological histology. Prior infection of orf virus apparently offers little protective immunity against future infections. Several gene products of orf virus have been identified as responsible for immunomodulatory functions. In our recent study of orf virus isolates from an area along the Minjiang River in northern Fujian Province, we found a high heterogeneity among isolates from 10 farms within a 120-kilometer distance. Only two isolates from locations within 1 km to each other had same viral genes. There is no correlation between the geographical distance between the corresponding collection sites and the phylogenetic distance in ORFV011 or ORV059 genes for any two isolates. This finding suggests that there are diverse populations of orf virus present in the environment. This may in part contribute to the phenomenon of recurring outbreaks and heighten the need for better surveillance.

Multiplex PCR for simultaneous detection and differentiation of sheeppox, goatpox and orf viruses from clinical samples of sheep and goats

A multiplex polymerase chain reaction (mPCR) was developed and evaluated for detection of pox viral infections simultaneously using clinical samples from sheep and goats. Specific primers for three pox viruses of sheep and goats including sheeppox virus (SPPV), goatpox virus (GTPV) and orf virus (ORFV) were designed targeting conserved sequences of the DNA binding phosphoprotein (I3L) coding gene of Capripoxvirus (CaPV) and the DNA polymerase (E9L) gene of parapoxvirus for identification of these viruses. The mPCR assay was found to be sensitive for detecting as low as 350 pg of viral genomic DNA or 10(2) copies of standard plasmid of individual targets; and 10(3) copies of plasmid in a mixture of two or three viruses. The assay was specific for detecting one or more of the viruses in various combinations from clinical specimens. Two hundred and thirty five (n=235) clinical samples from sheep and goats received from different geographical regions of the country for diagnosis of pox infection were evaluated by developed uniplex and mPCR assays. The assay had improved diagnostic sensitivity and specificity over to in-use laboratory diagnostic methods and can be useful for clinical differential diagnosis of these infections in sheep and goats.

Isolation and characterization of orf viruses from Korean black goats

Five cases of orf virus infection in Korean black goats were diagnosed in our laboratory between 2010 and 2011. One orf virus (ORF/2011) was isolated from an ovine testis cell line (OA3.Ts) for use as a vaccine candidate. Sequences of the major envelope protein and orf virus interferon resistance genes were determined and compared with published reference sequences. Phylogenetic analyses revealed that orf viruses from Korean black goats were most closely related to an isolate (ORF/09/Korea) from dairy goats in Korea. This result indicates that the orf viruses might have been introduced from dairy goats into the Korean black goat population.

Comparison of a loop-mediated isothermal amplification for orf virus with quantitative real-time PCR

Background

Orf virus (ORFV) causes orf (also known as contagious ecthyma or contagious papular dermatitis), a severe infectious skin disease in goats, sheep and other ruminants. Therefore, a rapid, highly specific and accurate method for the diagnosis of ORFV infections is essential to ensure that the appropriate treatments are administered and to reduce economic losses.

Methods

A loop-mediated isothermal amplification (LAMP) assay based on the identification of the F1L gene was developed for the specific detection of ORFV infections. The sensitivity and specificity of the LAMP assay were evaluated, and the effectiveness of this method was compared with that of real-time PCR.

Results

The sensitivity of this assay was determined to be 10 copies of a standard plasmid. Furthermore, no cross-reactivity was found with either capripox virus or FMDV. The LAMP and real-time PCR assays were both able to detect intracutaneous- and cohabitation-infection samples, with a concordance of 97.83%. LAMP demonstrated a sensitivity of 89.13%.

Conclusion

The LAMP assay is a highly efficient and practical method for detecting ORFV infection. This LAMP method shows great potential for monitoring the prevalence of orf, and it could prove to be a powerful supplemental tool for current diagnostic methods.