Simultaneous subtyping and pathotyping of the novel reassortant influenza A (H5N8) virus from clinical samples using a diagnostic microarray

Highly pathogenic avian influenza (HPAI) viruses cause economic losses in the poultry industry and pose a severe threat to human health. Rapid and accurate diagnostic methods are important because they can help prevent further spread of the virus and reduce the time required for eradication of the virus. We developed a low-density microarray for the rapid detection and identification of avian influenza virus subtypes H5, H7, and H9 and their pathotypes in a previous study. In the present study, we report the development of updated probe sets and evaluation of the diagnostic microarray using H5N8 clade 2.3.4.4 HPAI viruses including clinical samples, without the need for egg propagation. Cy3-labeled DNA targets were obtained by reverse transcription polymerase chain reaction using Cy3-labeled universal primers, and labeled amplicons were hybridized to the microarray. All positive samples from RT-PCR showed H5-specific and highly pathogenic pattern in the microarray, without purification of PCR products. Furthermore, it allowed for specific detection of the subtype and pathotype from low DNA concentration samples that did not allow direct sequence analysis. Therefore, this diagnostic microarray has enormous potential for the rapid subtyping and pathotyping from clinical samples without the need for culture.