A comprehensive high-throughput detection strategy: an indirect ELISA for serodetection of the novel aMPV/C in ducks

Abstract

Avian metapneumovirus subtype C (aMPV/C), a re-emerging and widespread epidemic in China, causes hydrosalpinx fluid syndrome (HFS) in laying ducks, resulting in significant economic losses to the poultry industry. In the absence of any licensed vaccines or antiviral drugs for aMPV/C, accurate diagnosis and timely eradication of the infected ducks remain the primary control measures, underscoring the urgent need for reliable and effective detection methods. In this study, the purified whole novel aMPV/C was used to develop an indirect enzyme-linked immunosorbent assay (iELISA) for the detection of aMPV/C antibodies in ducks. The cut-off value of the iELISA was determined to be 0.258. No cross-reactivity was observed with duck sera positive for antibodies against H5 AIV, NDV, DTMUV, BTV, DHAV-3, DPV, EDSV, MDPV, or GPV, demonstrating good specificity. Both intra-assay and inter-assay coefficients of variation were less than 10%, and the detection sensitivity of the iELISA reached a serum dilution of 1:102400. A total of 216 clinical serum samples from three duck breeds were tested via the established iELISA, of which 129 (59.7%) were positive. The concordance rate between the iELISA and an indirect immunofluorescence assay (IFA) was 100% (53/53). Overall, this cost-effective iELISA provides a reliable tool for the detection of aMPV/C antibodies in clinical diagnostics and epidemiological surveillance.