A rapid and visual detection for canine Adenovirus-2 using CRISPR-Cas13a-based SHERLOCK technology.

Abstract

Canine adenovirus type 2 (CAdV-2) is an important pathogen causing infectious tracheobronchitis (ITB) and viral enteritis in puppies, often exacerbating clinical symptoms through co-infection with other viruses. However, existing diagnostic methods for CAdV-2 exhibit notable limitations. Specifically, they are time-consuming, require additional nucleic acid purification steps, depend on expensive detection equipment, and necessitate operation by professional personnel. Collectively, these limitations prevent the achievement of rapid and accurate CAdV-2 detection in resource-limited settings. In this study, we established a novel CAdV-2 detection method by integrating CRISPR/Cas13a collateral cleavage activity with HUDSON rapid nucleic acid extraction, recombinase-aided amplification (RAA), and a lateral flow strip. This isothermal assay allows for visual, naked-eye result interpretation and achieves a sensitivity of 10copies/μL as read by lateral flow strips (corresponding to approximately 750 copies per reaction). It showed excellent specificity with no cross-reactivity observed against five other major canine viruses. When tested on 20 clinical samples, the assay demonstrated a 95 % concordance rate with the conventional simplex PCR results. The entire detection process is simple to perform, requires only basic equipment, and delivers results within 90 min. The developed CRISPR/Cas13a-based detection method exhibits significant application potential for CAdV-2 detection. This study develops a CRISPR/Cas13a-based point-of-care diagnostic tool for CAdV-2, delivering rapid, sensitive, and visual detection that significantly facilitates field-based pathogen surveillance and control efforts, while advancing the application of CRISPR diagnostics in veterinary infectious diseases.