Development of a colloidal gold nanoparticle-based lateral flow immunochromatographic (LFI) strip test for detecting Senecavirus A (SVA) antibodies in pigs using non-structural protein.

A rapid lateral flow immunochromatographic (LFI) strip test was developed to detect specific antibodies against the non-structural protein 3AB of Senecavirus A (SVA) in pig serum samples. Recombinant SVA 3AB non-structural protein, expressed in a baculovirus expression system and labeled with colloidal gold nanoparticles, was incorporated into the LFI strip, providing results within 15 min. When tested with 198 pig serum samples, the SVA 3AB LFI strip demonstrated a sensitivity of 97.97 % and a specificity of 90.00 % compared to the virus neutralizing assay (VNA), showing strong agreement (κ = 0.892). When compared to an in-house SVA 3AB indirect enzyme-linked immunosorbent assay (ELISA), the LFI strip exhibited a sensitivity of 98.62 % and a specificity of 86.79 %, with similarly strong concordance (κ = 0.880). The assay showed no cross-reactivity with serum samples from pigs infected with other common swine viruses. These findings suggest that the SVA 3AB LFI strip test is a high-performing, rapid, and easy-to-use diagnostic tool for detecting SVA antibodies in swine herds. It offers potential for monitoring herd immunity, supporting future SVA vaccination programs, and aiding in the control and prevention of SVA outbreaks.