Advances in Classical Swine Fever Virus molecular detection and characterization using the E2 gene as a diagnostic target

Abstract

Classical Swine Fever (CSF) is a transboundary viral disease that continues to cause significant economic losses to the swine industry in various countries. Efforts to control this disease are crucially dependent on the availability of rapid, highly sensitive diagnostic methods capable of providing reliable epidemiological data. Classical Swine Fever Virus (CSFV) is a single-stranded, positive-polarity RNA virus with a single open reading frame, in which the E2 gene encodes the main structural glycoprotein that plays a crucial role in the infection process, antigenic properties, and induction of the host immune response. These characteristics make the E2 gene the most widely used molecular target for CSFV detection and characterization. This review article aims to comprehensively examine the latest developments in CSFV molecular detection and characterization methods, with an emphasis on the use of the E2 gene as a diagnostic target. Various E2 gene-based molecular approaches, ranging from conventional RT-PCR, real-time PCR, isothermal amplification methods, to sequencing, are discussed based on their working principles, sensitivity and specificity levels, and their application in clinical diagnosis and field surveillance activities. Furthermore, the function of the E2 gene in phylogenetic analysis, strain origin tracing, and monitoring of CSFV genetic diversity was also reviewed, particularly in the context of outbreak dynamics and evaluating the effectiveness of vaccination programs. The review results indicate that the E2 gene has a balanced combination of sequence conservation and genetic variation, making it effective for both virus detection and characterization. However, several challenges remain, including sequence mutations, limited diagnostic facilities, and the need for method standardization. Therefore, the integration of the latest molecular technologies, the application of multi-target approaches, and the harmonization of E2 gene-based diagnostic protocols are expected to improve control success and support sustainable CSF eradication efforts.