Development and evaluation of an indirect ELISA based on recombinant structural protein VP2 to detect antibodies against duck hepatitis A virus

An indirect enzyme-linked immunosorbent assay (I-ELISA) based on the VP2 protein of duck hepatitis A virus type 3 (DHAV-3) was established in this study. The optimal dilutions of antigen, serum and goat anti-duck IgG conjugate were 1:1600 (2.23 μg/mL), 1:160 and 1:2000, respectively. The optimal blocking buffer was 1% skim milk. The cut-off value for the method was 0.25, and the analytical sensitivity of the method was 1:5120. The results of specific evaluation showed that except for DHAV-1, DHAV-3 antisera did not cross-react with any other common duck-sensitive pathogens, indicating that this method can be used to detect DHAV-3 and DHAV-1 antibodies. The coefficients of variation (CVs) were lower than 10 %. The coincidence rate between the VP2-DHAV-3-ELISA and the neutralization test was 93.3 %. In summary, the I-ELISA method based on VP2 protein has high sensitivity, specificity, and coincidence rate compared with the neutralization test and has advantages in serum monitoring. The I-ELISA method based on VP2 protein provides a simple and rapid method for the detection of anti-DHAV antibodies and the epidemiological monitoring of DHAV.