Rapid detection of
avian influenza virus (AIV)
infection is critical for control of
avian influenza (AI) and for reducing the risk of pandemic
human influenza. A double antibody sandwich
enzyme-linked
immunosorbent assay (
DAS-ELISA) was developed for this purpose. The method employed a
monoclonal antibody (MAb) as the capture antibody and rabbit polyclonal
IgG labeled with
horseradish peroxidase as the detector antibody, and both
antibodies were against type-specific
influenza A
nucleoprotein (NP). The
DAS-ELISA could detect minimally 2.5 ng of
influenza viral protein in virus preparations treated with
Triton X-100, which is equvilent to 2.5 x 10(2) EID50 virus particles. This
DAS-ELISA could detect all 15n AIV subtypes (H1-H15) and did not cross react with other avian pathogens tested. The
DAS-ELISA were directly compared with virus isolation (VI) in embryonated chicken eggs, the current standard of influenza virus detection, for 805 chicken samples. The
DAS-ELISA results correlated with VI results for 98.6% of these samples, indicating a sensitivity of 97.4% and specificity of 100%. The method was further tested with H5N1 and H9N2 AIV experimentally infected chickens, ducks, and pigeons, as well as field samples obtained from central China in 2005. The
DAS-ELISA method has demonstrated application potential as an AIV screening tool and as a supplement for virus isolation in Asia.