A novel recombinase polymerase amplification assay for rapid detection of epidemic fowl adenovirus

Real-time detection of Seneca Valley virus by one-tube RPA-CRISPR/Cas12a assay

Introduction

Senecavirus A (SVA) is a highly contagious virus that causes vesicular disease in pigs. At present, laboratory detection methods, such as virus isolation and polymerase chain reaction (PCR), required precision instruments and qualified personnel, making them unsuitable for point-of-care tests (POCT). Fortunately, the emergence of CRISPR/Cas system has provided new opportunities for fast and efficient pathogen detection.

Methods

This study successfully developed a precise and sensitive detection platform for diagnosing SVA by combining the CRISPR system with recombinase polymerase amplification (RPA).

Results

The minimum detection limit of the assay was 10 copies of the SVA genome. Meanwhile, the assay demonstrated high specificity. To validate the effectiveness of this system, we tested 85 swine clinical samples and found that the fluorescence method had a 100% coincidence rate compared to RT-qPCR.

Discussion

Overall, the RPA-CRISPR/Cas12a assay established in our study is a highly effective method for detecting SVA and holds great potential for practical applications in the resource-limited settings.

Development of a Real-Time Recombinase Polymerase Amplification Assay for the Rapid Detection of African Swine Fever Virus Genotype I and II

African swine fever (ASF) is a contagious viral disease in pigs and wild boars which poses a major threat to the pig industry. Rapid and accurate diagnosis is necessary to control ASF. Hence, we developed a rapid diagnostic method using a recombinase polymerase amplification (RPA) assay targeting the conserved sequences of CP204L (p30) thatcan rapidly detect ASF virus (ASFV) genotype strains I and II. The lower detection limit of the real-time RPA assay was 5 × 101 copies per reaction. The real-time RPA assay effectively detected ASFV isolates and clinical specimens belonging to ASFV genotypes I and II. The sensitivity and specificity of the assay were 96.8% (95% confidence interval (CI): 83.3−99.9) and 100% (95% CI: 88.4−100.0), respectively. The agreement between the real-time RPA assay and a reference commercial real-time quantitative polymerase chain reaction (qPCR) was 100%. The real-time RPA assay had a detection time of 6.0 min (95% CI: 5.7−6.2), which was significantly shorter than that of qPCR (49 min; 95% CI: 47.4−50.6; p < 0.001). Thus, the developed real-time RPA assay is a rapid and accurate diagnostic tool for detecting ASFV genotypes I and II.