Development and validation of a point-of-care molecular assay for sacbrood virus (SBV) diagnosis in apiaries

Sacbrood virus (SBV) is a significant pathogen affecting honeybee health, leading to substantial economic losses in apiculture. Although traditional methods, like reverse transcription quantitative polymerase chain reaction, offer accurate detection and quantification of SBV, they have limitations for use in field settings, such as apiaries. Here, we developed and evaluated the XQ SBV Dx Kit as a diagnostic tool for the XQ Station point-of-care (POC) RT-qPCR device, which integrates nucleic acid extraction, gene amplification, and detection for on-site molecular diagnosis. Diagnostic performance was assessed using clinical samples infected with SBV and was compared with that of standard laboratory-based RT-qPCR. The limit of detection (LOD) for both methods was 10² copies per reaction, with the XQ SBV Dx Kit consistently demonstrating superior sensitivity, detecting 83.3 % of replicates at 10¹ copies per reaction compared to 58.3 % with RT-qPCR. Specificity testing against 11 other honeybee pathogens confirmed the absence of cross-reactivity, highlighting the diagnostic precision of the XQ SBV Dx Kit. Clinical evaluation revealed 98.4 % sensitivity and 97.0 % specificity, validating its reliability for field applications. Overall, the XQ SBV Dx Kit is an essential advancement in honeybee health management, offering practical and timely solutions for supporting sustainable apicultural practices.