Development and evaluation of a nanozyme-based lateral flow assay strip for avian leukosis virus detection

Avian leukosis (AL) is a common neoplastic disease in poultry caused by the Avian leukosis virus (ALV). As there are no specific drugs or vaccines for preventing and treating this disease, population purification is currently primarily achieved by culling affected individuals and selecting and breeding leukemia-free chicken flocks. To address the lack of a rapid and accurate ALV detection method, this study developed a lateral flow strip detection system based on Fe-Co nanozyme-antibody probes. Owing to the efficient signal amplification property of nanozymes, the system significantly improved detection sensitivity, with a minimum detection limit of 12.5 TCID₅₀/mL for ALV and 0.20 ng/mL for its related proteins. Furthermore, this test strip was eight times more sensitive than the commercial enzyme-linked immunosorbent assay (ELISA) group-specific antigen detection kit. Specificity verification results showed that the detection test strip only produced a positive reaction to ALV and no cross-reactions with six common avian viruses, namely Newcastle disease virus (NDV), Marek's disease virus (MDV), infectious bursal disease virus (IBDV), fowlpox virus (FPV), infectious laryngotracheitis virus (ILTV), and avian influenza virus (AIV). Additionally, the strip exhibited excellent intra- and inter-batch repeatability, with the corresponding coefficient of variation (CV) being less than 10 %. Clinical sample detection data indicated that the results of the nanozyme-based test strip were consistent with those of the commercial double-antibody sandwich ELISA detection kit, achieving a coincidence rate of up to 100 %. Collectively, the results of this study provide a novel technical method characterized by high sensitivity, high specificity, and simple operation for the on-site rapid screening of ALV.