Development of a novel real-time PCR assay targeting p54 gene for rapid detection of African swine fever virus (ASFV) strains circulating in Vietnam.

African swine fever (ASF) continues to cause outbreaks throughout regions of Africa, Europe and Asia. The disease can cause severe morbidity and mortality resulting in serious economic losses. Since there is no vaccine available to control ASF, early detection is critical to contain and control the disease. The aim of this study was to develop a novel real-time PCR assay based on highly conserved ASFV gene E183L (p54). The limit of detection of the assay, VNUA-p54 real-time PCR, was 2.63 copies/reaction and 2 Log10 HAD50 /ml. The VNUA-p54 real-time PCR was able to detect fifteen different ASFV reference strains representing p72 genotypes I, II and V. The assay was specific and did not amplify other swine viruses including CSFV, FMDV, PRRSV and PEDV. The diagnostic sensitivity of the real-time PCR assay was evaluated using 200 field clinical specimens collected from swine farms located in different provinces in Vietnam. The VNUA-p54 real-time PCR assay is an additional tool for ASF diagnostics and can be used in combination with other p72 based ASFV real-time PCR assays as a rapid confirmatory assay.