Recent advances in diagnostic approaches for orf virus

Abstract

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 Keywords Orf virus • Diagnostic approach • Conventional methods • Serological methods • Molecular methods

A solitary finger nodule with a papulovesicular hands and feet eruption: a complicated human Orf virus infection

“…In addition, different virus can be simultaneously detected. [12]. No molecular test was performed in our patients, as both clinical, epidemiological and histological features were compatible with the same diagnosis of a complicated human Orf virus infection.…”

“…According to the literature, only a limited number of patients undergo a biopsy. [12]. For ORFV detection, a number of molecular-based diagnostic methods have used, including polymerase chain reaction (PCR), real-time PCR, loop-mediated isothermal ampli cation-based assay, RPA assay, and RAA test.…”

“…Numerous duplex and multiplex PCR techniques have been developed and are being used for ORFV detection in addition to single-gene PCR. [12] A real-time method for ORFV diagnosis was developed because standard PCR procedures are nonquantitative, time-consuming and often leading to nonspeci c ampli cation. [13] Realtime quantitative PCR assays have signi cant bene ts over conventional PCRs, including high throughput, great sensitivity and speci city, and reduced time and labor requirements.…”

Human Orf with Immune-Mediated Reactions: A Systematic Review

“…Regarding Orf diagnosis in humans, according to our systematic review, it was mostly made on the basis of clinical and epidemiological history, while biopsy was performed only in a small percentage of cases [ 17 ]. However, considering the wide spectrum of immunological reactions, as well as the poor experience of many clinicians, histopathological examination and direct immunofluorescence may help in achieving a prompt diagnosis.…”

“…It is considered a type IV hypersensitivity reaction, which typically presents with targetoid lesions on the skin and sometimes on the mucosa, usually following exposure to certain infections (90% of cases), and less commonly to drugs [ 15 , 16 ]. The diagnosis in humans is usually based on the anamnesis and the clinical features [ 17 ]. However, because of the extensive clinical differential diagnosis of primary lesions and secondary immunological reactions, as well as the unfamiliarity of many physicians with this disease, especially in areas where it is uncommon, currently Orf is under-recognized, often leading to delayed diagnosis and inappropriate treatments [ 18 , 19 ].…”