Orf, a Human Parapoxvirus Infection.

Despite being common worldwide, parapoxvirus infections are regarded as neglected zoonoses because their incidence is either unknown or grossly overestimated. In ruminants all throughout the world, parapoxvirus produces oral lesions and infectious pustular dermatitis. The pathogen is typically spread directly via items contaminated with parapoxvirus and indirectly via a near contact with dermatological lesions that contain the virus on affected animals. Animals infected with the parapoxvirus typically exhibit no clinical symptoms, and the mode of parapoxvirus transmission is occasionally unclear. For accurate etiological diagnosis and appropriate therapy of patients affected by zoonotic infections, the significance of adopting a "One Health" approach and cross-sector collaboration between human and veterinary medicine should be emphasized. The causative pathogen of ecthyma contagiosum in general people is the orf virus, which mostly infects various animals, either pets or wildlife species. The illness primarily affects minute wild ruminants, sheep, cattle, deer, and goats, and it can spread to people through contact with infected animals or contaminated meats anywhere in the world. Taxonomically speaking, the virus belongs to the parapoxvirus genus. Thus pathogen can be detected from crusts for a very long period (several months to several years), and the virus is found to be resistant to inactivation with a hot or dry atmosphere. In immunocompetent individuals, the lesions often go away on their own with a period as long 2 months. Nevertheless, it necessitates the applying of diverse strategies, such as antiviral, immunological modulator, or modest surgical excisions in immunosuppressed patients. The interaction of the virus with various host populations aids in the development of a defense mechanism against the immune system. The parapoxvirus illness in humans is covered in this chapter. The orf illness, a significant known human parapoxvirus infection, is given specific attention.

Preparation and application of fluorescent monoclonal antibodies recognizing goat CD4+CD25+ regulatory T cells.

Regulatory T cells (Tregs) are a subset of T cells participating in a variety of diseases including mycoplasmal pneumonia, contagious ecthyma, and so on. The role of Tregs in goat contagious ecthyma is not completely understood due to the lack of species-specific antibodies. Here, we developed a combination of CD4 and CD25 fluorescence monoclonal antibodies (mAb) to recognize goat Tregs and assessed its utility in flow cytometry, immunofluorescence staining. Using immunofluorescence staining, we found that the frequency of Treg cells was positively correlated with the viral load during orf virus infection. These antibodies could serve as important tools to monitor Tregs during orf virus infection in goats. KEY POINTS: • A combination of fluorescent mAbs (C11 and D12) was prepared for the detection of goat Tregs. • C11 and D12 are effective in flow cytometry, immunofluorescence staining, and C11 has excellent species specificity. • The frequency of Treg cells was positively correlated with the viral load during orf virus infection.

Participatory epidemiology on major camel calf health and management problems in pastoral and semi-pastoral zones of Somali region, Ethiopia.

A cross-sectional study was conducted from May 2017 to March 2019. A participatory epidemiological appraisal was used to gain a rapid overview of the range of camel calf health problems and traditional management, a measure of the importance that people place on each of them, and to identify and prioritize economically important diseases in target zones. The most important constraints to camel production were identified to be the widespread prevalence of diseases such as camelpox, contagious ecthyma, calf scour, ticks, and nonspecific pneumonia; poor management and husbandry practices such as restrictive colostrum feeding, lack of concentrate and salt supplementation and inappropriate housing; shortage of feed; and scarce seasonal variation in water. Additionally, the livestock herders not only showed their knowledge of common camel calf diseases for affected organs and symptoms but also indicated the seasonality of disease occurrences with strong agreement (W = 0.899, P< 0.003) among the informants of all focus group discussions. The overall prevalence of mange, tick infestation, and bacteria-induced diarrhea in the study area was found to be 36.3%, 36%, and 74%, respectively. Sarcoptes scabie var. cameli was the only identified mite species from mange-infested calves, while Hyalomma, Rhipicephalus, and Amblyoma were the most commonly identified tick species. Similarly, the overall prevalence of diarrhea was 74% among this about 34.6% was caused by E. coli while 38.9% was affected by Salmonella and E. coli. Therefore, based on these findings, five diseases have been prioritized as the most significant calf diseases in the area (Camelpox, contagious ecthyma, and causes of pneumonia among camel calves). Improving veterinary health infrastructure and capacity, and increasing community awareness on camel health constraints are also recommended to enhance optimal camel calf rearing.

Human orf virus (family Poxviridae) infection following a lamb bite in Hungary.

Human orf disease (called ecthyma contagiosum or contagious/infectious pustular dermatitis in animals) was confirmed on the fingers of both hands of a 24-year-old female, after feeding diseased lambs with a nursing bottle in April 2023. In addition to skin symptoms, she had low-grade fever (37.6°C) and swollen lymph nodes in both axilla. The presence of orf virus (genus Parapoxvirus, family Poxviridae) was confirmed, and this strain, Baja/2023/HUN (OR372161-OR372163), was found to have > 98% nucleotide sequence identity to sheep-origin orf viruses in four tested genome regions (ORF011/B2L, ORF019, ORF020/VIR, and ORF056). This is the first report of a human case of infection with the neglected zoonotic orf virus in Hungary.

Use of a local anaesthetic and antiseptic wound formulation for the treatment of lambs naturally infected with Orf virus.

Contagious ecthyma (CE) is a worldwide highly contagious zoonotic viral skin disease of sheep and goats. Treatment for Orf virus (ORFV) infection usually involves topical and oral antibiotics. An anaesthetic and antiseptic topical gel (Multisolfen® or Tri-Solfen®; MS®, Medical Ethics, Australia) has been documented as an efficacious therapy for lesions from mucosal and epithelial viral infections in ruminants. The present study tested a new treatment protocol of MS® for CE therapy on-farm in 150 lambs naturally infected with ORFV. Lambs were divided into three cohorts of 50 lambs each (C, D and E). Cohort C was treated with MS® 3 times with an interval of 3 days between treatments, cohort D was treated daily with hypochlorous acid, whilst cohort E served as untreated controls. The lambs were examined clinically every two days, weight measured weekly, with whole blood and sterile swabs from ORFV lesions collected for haematological analysis and specific ORFV PCR. Cohort C presented fewer lambs displaying ORFV-associated lesions than other cohorts at different times of the experiment. Further, lesions treated with MS® were milder compared with other cohorts. However, following cessation of therapy, most of the lambs again developed ORFV-associated lesions. No differences between cohorts were observed in weight, haematological and PCR results. These findings suggest that topical treatment with MS® is effective for CE in field conditions, especially in the first stages of the clinical course, although treatment with MS® may need to be extended a minimum of 4 weeks.

Development of an indirect ELISA against Orf virus using two recombinant antigens, partial B2L and F1L.

Orf is a highly contagious viral disease affecting goats and sheep. It is caused by Orf virus (ORFV) and has caused severe economic losses to the global goat industry, including in China. In this study, an indirect ELISA method for recombinant proteins based on truncated dominant antigenic epitopes of B2L and F1L genes of ORFV was established. A series of conditions and its performance were comprehensively evaluated. The optimized ELISA reaction conditions were: the optimal coating amount of antigen was 0.25 µg/mL, 5% skim milk powder was closed for 1 h, the optimal dilution of serum was 1:200, the optimal incubation time of the rabbit anti-goat IgG was 1:8000, the optimal color development time of TMB was 15 mins, and the threshold value of negative-positive was 0.358. The method specifically detects anti-ORFV antibodies and does not cross-react with positive sera for other common goat pathogenic bacteria antiserum. ORFV-positive sera were still positive after 1:512 dilution, with intra-batch coefficient of variation (CV) between 7.1% and 9.5% and inter-batch CV between 5.0% and 7.6%; 51% (92/180) of immunized goat serum samples were tested positive and 14.44% (14/63) of non-immunized goat serum samples were positive. The results show that the indirect ELISA antibody assay established in this study has good specificity, sensitivity and reproducibility, and provides a technical tool for clinical ORFV serum antibody detection and epidemiological investigation.

Detection and genetic characterization of orf virus from sheep and goats in Nigeria.

Orf is a contagious, viral epitheliotropic disease of small ruminants. We investigated the molecular epidemiology of orf virus (ORFV) in breeds of small ruminants to determine the evolutionary diversity in Nigeria. Out of 54 small ruminants screened, the number of animals that were positive for ORFV in the three locations were 25. The distribution of positive animals by location were FCT 45.0% (n = 9/20), Oyo State 42.9% (6/14), and Plateau State 50.0% (n = 10/20). ORFV sequences from this study clustered with viruses detected in Taiwan, Iran, USA, and France. Our findings highlight the risk of transmission across geographic boundaries in Nigeria and West Africa, and reinforces the need for increased surveillance to prevent and control spread. Comprehensive characterization of ORFV in small ruminants as well as in humans in Nigeria is required to better elucidate the epidemiological dynamics and the virus evolution.

An evaluation of the ecological niche of Orf virus (Poxviridae): Challenges of distinguishing broad niches from no niches.

Contagious ecthyma is a skin disease, caused by Orf virus, creating great economic threats to livestock farming worldwide. Zoonotic potential of this disease has gained recent attention owing to the re-emergence of disease in several parts of the world. Increased public health concern emphasizes the need for a predictive understanding of the geographic distributional potential of Orf virus. Here, we mapped the current distribution using occurrence records, and estimated the ecological niche in both geographical and environmental spaces. Twenty modeling experiments, resulting from two- and three-partition models, were performed to choose the candidate models that best represent the geographic distributional potential of Orf virus. For all of our models, it was possible to reject the null hypothesis of predictive performance no better than random expectations. However, statistical significance must be accompanied by sufficiently good predictive performance if a model is to be useful. In our case, omission of known distribution of the virus was noticed in all Maxent models, indicating inferior quality of our models. This conclusion was further confirmed by the independent final evaluation, using occurrence records sourced from the Centre for Agriculture and Bioscience International. Minimum volume ellipsoid (MVE) models indicated the broad range of environmental conditions under which Orf virus infections are found. The excluded climatic conditions from MVEs could not be considered as unsuitable owing to the broad distribution of Orf virus. These results suggest two possibilities: that the niche models fail to identify niche limits that constrain the virus, or that the virus has no detectable niche, as it can be found throughout the geographic distributions of its hosts. This potential limitation of component-based pathogen-only ENMs is discussed in detail.

The Global Evolutionary History of Orf Virus in Sheep and Goats Revealed by Whole Genomes Data.

Orf virus (ORFV) belongs to the genus Parapoxvirus (Poxviridae family). It is the causative agent of contagious ecthyma (CE) that is an economically detrimental disease affecting small ruminants globally. Contagious ecthyma outbreaks are usually reported in intensive breeding of sheep and goats but they have also been reported in wildlife species. Notably, ORFV can infect humans, leading to a zoonotic disease. This study aims to elucidate the global evolutionary history of ORFV genomes in sheep and goats, including the first genomes from Central America in the analyses. In comparison to the last study on ORFV whole genomes, the database now includes 11 more sheep and goat genomes, representing an increase of 42%. The analysis of such a broader database made it possible to obtain a fine molecular dating of the coalescent time for ORFV S and G genomes, further highlighting the genetic structuring between sheep and goat genomes and corroborating their emergence in the latter half of 20th century.

Finger nodules with a papulovesicular hands and feet eruption: a complicated human Orf virus infection.

BACKGROUND: Orf virus (ORFV) is the pathogen responsible for Orf, a zoonotic viral infection that can be spread to humans from sheep and goats. Here, we present a case of human Orf complicated by an immune-related reaction, to raise awareness of this under-recognized disease avoiding unnecessary investigations and overtreatment. CASE REPORT: A 51-year-old woman with no previous medical history presented with a one-week history of three asymptomatic swelling nodules with a grey necrotic center and red outer halo on her index finger. At physical examination there was also a pruritic papulovesicular eruption on her hands and feet. She reported a recent contact with a goat which had a similar nodular lesion in its mouth. A biopsy of the lesions was performed and a diagnosis of Orf complicated by widespread erythema multiforme was made based on the clinical and histopathological features. The lesions spontaneously resolved within the next 2 weeks. CONCLUSIONS: Orf is not very prevalent in our region, so we performed a biopsy of the lesion to guide us toward a diagnosis. However, we should remember that the diagnosis of ecthyma relies on clinical evaluation and epidemiological criteria.

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.

ORFV entry into host cells via clathrin-mediated endocytosis and macropinocytosis.

Orf virus (ORFV), also known as infectious pustular virus, leads to an acute contagious zoonotic infectious disease. ORFV can directly contact and infect epithelial cells of skin and mucosa, causing damage to tissue cells. So far, the pathway of ORFV entry into cells is unclear. Therefore, finding the internalization pathway of ORFV will help to elucidate the cellular and molecular mechanisms of ORFV infection and invasion, which in turn will provide a certain reference for the prevention and treatment of ORFV. In the present study, chemical inhibitors were used to analyze the mechanism of ORFV entry into target cells. The results showed that the inhibitor of clathrin-mediated endocytosis could inhibit ORFV entry into cells. However, the inhibitor of caveolae-mediated endocytosis cannot inhibit ORFV entry into cells. In addition, inhibition of macropinocytosis pathway also significantly reduced ORFV internalization. Furthermore, the inhibitors of acidification and dynamin also prevented ORFV entry. However, results demonstrated that inhibitors inhibited ORFV entry but did not inhibit ORFV binding. Notably, extracellular trypsin promoted ORFV entry into cells directly, even when the endocytic pathway was inhibited. In conclusion, ORFV enters into its target cells by clathrin-mediated endocytosis and macropinocytosis, while caveolae-dependent endocytosis has little effects on this process. In addition, the entry into target cells by ORFV required an acid environment and the effect of dynamin. Meanwhile, we emphasize that broad-spectrum antiviral inhibitors and extracellular enzyme inhibitors are likely to be effective strategies for the prevention and treatment of ORFV infection.

Genetic Analysis of Orf Virus (ORFV) Strains Isolated from Goats in China: Insights into Epidemiological Characteristics and Evolutionary Patterns.

Contagious ecthyma (CE) is an acute infectious zoonosis caused by orf virus (ORFV) that mainly infects sheep and goats and causes obvious lesions and low market value of livestock, resulting in huge economic losses for farmers. In this study, two strains of ORFV were isolated from Shaanxi Province and Yunnan Province in China, named FX and LX. The two ORFVs were located in the major clades of domestic strains respectively, and exhibited distinct sequence homology. We analyzed the genetic data of core genes (B2L, F1L, VIR, ORF109) and variable genes (GIF, ORF125 and vIL-10) of ORFV to investigate its epidemiological and evolutionary characteristics. The sequences from 2007 to 2018 constituted the majority of the viral population, predominantly concentrated in India and China. Most genes were clustered into SA00-like type and IA82-like type, and the hotspots in East and South Asia were identified in the ORFV transmission trajectories. For these genes, VIR had the highest substitution rate of 4.85 × 10-4, both VIR and vIL-10 suffered the positive selection pressure during ORFV evolution. Many motifs associated with viral survival were distributed among ORFVs. In addition, some possible viral epitopes have been predicted, which still require validation in vivo and in vitro. This work gives more insight into the prevalence and phylogenetic relationships of existing orf viruses and facilitate better vaccine design.

The orf virus 129 protein can inhibit immune responses by interacting with host complement C1q binding protein in goat turbinate bone cells.

OBJECTIVE: Contagious ecthyma is a severe and highly contagious disease caused by an orf virus (ORFV). The virus is responsible for substantial economic losses in the goat industry and threatens humans. We previously determined the role of ORFV129 protein, one of the five ankyrin-repeat proteins coded by the orf genome, in suppressing the transcription of pro-inflammatory cytokines IL-6, IL-1ß and IFN-γ. In the present study, we identified 14 cellular proteins (complement C1q binding protein [C1QBP], MCM7, EIF5A, PKM, SLC6A, TSPAN6, ATP6AP2, GPS1, MMADHC, HSPB6, SLC35B1, MTF1, P3H4, and IL15RA) that interact with ORFV129 using a yeast two-hybrid system in goat turbinate bone cells (GFTCs). The interaction between ORFV129 and (C1QBP), an immune-related protein, was confirmed using immunofluorescence co-localization and co-immunoprecipitation assays. C1QBP overexpression inhibited ORFV replication, whereas the knockdown of C1QBP promoted ORFV replication in GFTCs. Furthermore, ORFV or ORFV129 increased C1QBP expression in GFTCs, indicated that ORFV129-C1QBP interaction might contribute to the ORFV-induced host immune process. In addition, our research showed that ORFV increased the expression of ORFV129, cytokine IL-6, IL-1ß and IFN-γ. C1QBP overexpression induced IFN-γ production and reduced IL-6 and IL-1ß production. Conversely, C1QBP knockdown induced IL-1ß production and reduced IFN-γ and IL-1ß production. Moreover, augmentation of ORFV129 expression enhanced the inhibition of the secretion of cytokines IL-6, IL-1ß, and IFN-γ induced by the altered expression of C1QBP. These findings suggest different downstream pathways might be involved in regulating different cytokines induced by ORFV129 expression in GFTCs.

Host range, severity and trans boundary transmission of Orf virus (ORFV).

Contagious ecthyma in small ruminants is a zoonotic disease caused by Orf virus (ORFV) in the genus Parapoxvirus that can be deadly to its natural hosts. It causes significant losses worldwide, and commonly infects humans. However, the literature about its comparative severity in sheep and goat hosts is misleading; and while contagious ecthyma has been shown to occur in camels and transmit to humans, there is confusion as to whether ORFV is responsible. Camels are important from a 'One Health' perspective as they have been implicated as a reservoir host for the virus causing Middle East Respiratory Syndrome (MERS), which has a case fatality rate of 35% in humans. We compared ORFV gene sequences and mortality data from the West Bank in Palestine, where ORFV has not been reported previously, with data from the region. Surprisingly, we found that infections of camels that had been attributed to ORFV were more closely related to a different member of the genus Parapoxvirus. Two Middle East ORFVs isolated from humans were unrelated and sat alongside sheep and goat derived sequences on two distinct ORFV lineages of a maximum likelihood B2L gene tree. One of the viral lineages bifurcated to produce a monophyletic group of goat-derived ORFVs characterized uniquely by a glycine at amino acid reside 249. We found that serine is the ancestral allele shared between ORFV infections of sheep and also two closely related Parapoxviruses (PCPV and CCEV), indicating that the glycine allele represents a more recent shift in virus host range adaptation to goats. Furthermore, and contrary to some reports that ORFV is more severe in goats than in sheep, we observed median mortality of up to 24.5% in sheep, but none in goats. We also identified trans-boundary spread of ORFV between the West Bank and Israel.

Orf Nodule with Erythema Multiforme during a Monkeypox Outbreak, France, 2022.

A 26-year-old patient in France who worked as a butcher sought care initially for erythema multiforme. Clinical examination revealed a nodule with a crusty center, which upon investigation appeared to be an orf nodule. Diagnosis was confirmed by PCR. The patient was not isolated and had a favorable outcome after basic wound care.

Recent advances in diagnostic approaches for orf virus.

Orf virus (ORFV), the prototype species of the Parapoxvirus genus, is an important zoonotic virus, causing great economic losses in livestock production. At present, there are no effective drugs for orf treatment. Therefore, it is crucial to develop accurate and rapid diagnostic approaches for ORFV. Over decades, various diagnostic methods have been established, including conventional methods such as virus isolation and electron microscopy; serological methods such as virus neutralization test (VNT), immunohistochemistry (IHC) assay, immunofluorescence assay (IFA), and enzyme-linked immunosorbent assay (ELISA); and molecular methods such as polymerase chain reaction (PCR), real-time PCR, loop-mediated isothermal amplification (LAMP), recombinase polymerase amplification (RPA), and recombinase-aided amplification (RAA) assay. This review provides an overview of currently available diagnostic approaches for ORFV and discusses their advantages and limitations and future perspectives, which would be significantly helpful for ORFV early diagnosis and surveillance to prevent outbreak of orf. KEY POINTS: • Orf virus emerged and reemerged in past years • Rapid and efficient diagnostic approaches are needed and critical for ORFV detection • Novel and sensitive diagnostic methods are required for ORFV detection.

Deletion of gene OV132 attenuates Orf virus more effectively than gene OV112.

Orf virus (ORFV), a Parapoxvirus in Poxviridae, infects sheep and goats resulting in contagious pustular dermatitis. ORFV is regarded as a promising viral vector candidate for vaccine development and oncolytic virotherapy. Owing to their potential clinical application, safety concerns have become increasingly important. Deletion of either the OV132 (encoding vascular endothelial growth factor, VEGF) or OV112 (encoding the chemokine binding protein, CBP) genes reduced ORFV infectivity, which has been independently demonstrated in the NZ2 and NZ7 strains, respectively. This study revealed that the VEGF and CBP gene sequences of the local strain (TW/Hoping) shared a similarity of 47.01% with NZ2 and 90.56% with NZ7. Due to the high sequence divergence of these two immunoregulatory genes among orf viral strains, their contribution to the pathogenicity of Taiwanese ORFV isolates was comparatively characterized. Initially, two ORFV recombinants were generated, in which either the VEGF or CBP gene was deleted and replaced with the reporter gene EGFP. In vitro assays indicated that both the VEGF-deletion mutant ORFV-VEGFΔ-EGFP and the CBP deletion mutant ORFV-CBPΔ-EGFP were attenuated in cells. In particular, ORFV-VEGFΔ-EGFP significantly reduced plaque size and virus yield compared to ORFV-CBPΔ-EGFP and the wild-type control. Similarly, in vivo analysis revealed no virus yield in the goat skin biopsy infected by ORFV-VEGFΔ-EGFP, and significantly reduced the virus yield of ORFV-CBPΔ-EGFP relative to the wild-type control. These results confirmed the loss of virulence of both deletion mutants in the Hoping strain, whereas the VEGF-deletion mutant was more attenuated than the CBP deletion strain in both cell and goat models. KEY POINTS: • VEGF and CBP genes are crucial in ORFV pathogenesis in the TW/Hoping strain • The VEGF-deletion mutant virus was severely attenuated in both cell culture and animal models • Deletion mutant viruses are advantageous vectors for the development of vaccines and therapeutic regimens.