Development of Microsphere-Based Multiplex Branched DNA Assay for Detection and Differentiation of Avian Influenza Virus Strains

We developed and evaluated a multiplex branched DNA assay for the detection and subtyping of avian influenza (AI) virus strains. The assay successfully detected all 94 AI virus strains of 15 different hemagglutinin (HA) subtypes tested while simultaneously differentiating 24 North American H5, 11 Eurasian H5, and 11 H7 strains. Our study demonstrates for the first time that a branched DNA method can detect targets that show a great amount of sequence variation.