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.

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.

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.

Orf Virus in Humans: Case Series and Clinical Review.

Ecthyma contagiosum (orf), a worldwide cause of the hand pustule, is caused by orf virus, a member of the genus Parapoxvirus, which causes an epitheliotropic zoonotic infection that spreads from ruminants (even-toed ungulate mammals such as sheep or goats) to humans. Similar members within the poxvirus family can cause a clinically identical viral pustule, which is spread to humans from the respective animal host reservoirs. These entities are impossible to clinically differentiate in the absence of social history or specific polymerase chain reaction studies, though their frequency does vary based on location across the globe.Although its 1-cm solitary hand pustule often is easily diagnosed by the experienced dermatologist, the goal of this review is to expand the understanding of the presentation, differential diagnosis, and treatment of this condition. We present 5 clinical cases of orf. Special care also has been taken to expand on our report of the unique associated cultural and social elements that the expert diagnostician should obtain to determine etiology.Early and rapid diagnosis of this classic condition are critical to prevent unnecessary biopsies or extensive testing, and determination of etiology can be important to prevent reinfection or spread to other humans by the same infected animal.

Solitary Subungual Orf.

Orf-ecthyma contagiosum-is an endemic cutaneous disease caused by parapoxvirus that is transmitted via direct contact with contagious animals. The lesions are located frequently on the hands and fingers. Subungual presentation of orf is very rare. We report a case of solitary subungual orf. Suspicious subungual nodular lesions may be cases of orf, especially in endemic areas. Orf disease should be considered in the differential diagnosis of subungual nodular lesions to avoid unnecessary surgical interventions.

Orf progressiva: giant progressive and destructive infections in the immunocompromised.

Orf virus causes a self-limited infection in humans that resolves without scarring within 6-12 weeks. However, lesions in the immunocompromised can be progressive and disfiguring. The lesions frequently recur after treatment. To our knowledge, there are eleven published cases of these infections. We propose the name orf progressiva to call attention to this progressive, treatment-resistant entity. We present a 43-year-old male ranch owner with a history of renal transplantation who contracted an orf infection from his lamb. The infection recurred despite attempts at debridement, but achieved near complete resolution after treatment with imiquimod and valacyclovir. The histologic findings of orf progressiva are identical to the early stages of classic orf infection and are characterized by epithelial hyperplasia, intracytoplasmic eosinophilic inclusions, and an edematous, vascular dermis. There is no standard treatment for orf progressiva. Surgical excision has frequently resulted in rapid reoccurrence. Topical therapies such as imiquimod and cidofovir cream in combination with excision have been successful in some cases. Acyclovir or valacyclovir with imiquimod has been reported to be effective. Two patients achieved cure with imiquimod alone. We summarize these cases to prompt recognition of orf progressiva as a distinct clinical entity that requires treatment.

Orf (Ecthyma Contagiosum) Transmitted from a Camel to a Human: A Case Report.

BACKGROUND Orf, also known as ecthyma contagiosum, is a zoonotic disease caused by a parapox virus, which is endemic in goats and sheep but rare in camels. Orf is usually transmitted to humans who are in contact with infected animals. The clinical manifestation of the disease and a personal history of contact with an infected animal are sufficient to diagnose orf virus infection. CASE REPORT In this case report, we present a 42-year-old man with an unremarkable medical history who came into contact with an infected camel and developed a typical orf lesion. There were multiple erythematous, dome-shaped to round painless nodules on the right forearm of the patient. Some of them had coalesced, forming large plaques, and a few nodules had watery or yellowish discharge. The lesion was complicated by lymphadenopathy. The diagnosis of orf was made based upon clinical suspicion. The patient was treated with fusidic acid cream and observed until the lesion resolved spontaneously, leaving some post-inflammatory hyperpigmentation. We believe this is the first report of orf transmission from a camel to a human. CONCLUSIONS All physicians should consider this disease as a differential diagnosis in any patient who has a history of contact with camels. Although orf is a self-limiting condition, its early clinical recognition is critical to avoid complications, unwarranted psychological stress, and unnecessary surgical intervention.

Development of a recombinase-aided amplification assay for detection of orf virus.

Orf, caused by orf virus (ORFV), is an important zoonotic disease that infects goat and sheep, leading to huge economic losses. ORFV can also cause cutaneous lesions in people who come in close contact with the diseased animals. Although accurate diagnostic methods for ORFV infection exist, there is a need for a rapid, specific, and sensitive method for easy clinical application. Here, we successfully established a recombinase-aided amplification (RAA) assay for rapid detection of ORFV. The analytical sensitivity of the assay for ORFV detection is 1 × 101 copies per reaction. Moreover, no cross-reaction was observed with other common DNA viruses. A total of 45 archived suspected ORFV infected nasal scab skin samples were examined by RAA and SYBR Green-based real-time polymerase chain reaction (PCR). Compared with the real-time PCR assay, the kappa values of the RAA assay for ORFV detection was 0.845 (p <0.001), indicating that both assay results were fully in agreement. In conclusion, this detection assay provides a rapid, sensitive, and specific method for ORFV detection and is suitable for ORFV clinical testing.

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.

Human Infection with Orf Virus and Description of Its Whole Genome, France, 2017.

Zoonotic transmission of parapoxvirus from animals to humans has been reported; clinical manifestations are skin lesions on the fingers and hands after contact with infected animals. We report a human infection clinically suspected as being ecthyma contagiosum. The patient, a 65-year-old woman, had 3 nodules on her hands. She reported contact with a sheep during the Aïd-el-Fitr festival in France during 2017. We isolated the parapoxvirus orf virus from these nodules by using a nonconventional cell and sequenced the orf genome. We identified a novel orf virus genome and compared it with genomes of other orf viruses. More research is needed on the genus Parapoxvirus to understand worldwide distribution of and infection by orf virus, especially transmission between goats and sheep.

Feast of Sacrifice and Orf, Milan, Italy, 2015-2018.

Orf (ecthyma contagiosum) is an infection of the skin caused by a DNA virus belonging to the genus Parapoxvirus. We recently observed 7 cases of orf in Muslim men living in the metropolitan area of Milan, Italy, who acquired the infection after the Feast of Sacrifice.

Nódulo eritematoso en un niño / Erythematous nodule in a child

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