IRF7 and viral infectious disease: Although there is a considerable advance in the understandings of the innate immune evasion by avian viruses that was mainly attributable to the results from those studies on host PRRs, the IRF7/NF-κB signal transduction pathway and the IFNAR-JAK-STAT signal transduction pathway during viral infection, little information is available regarding the innate immune evasion by avian viruses via pyroptosis, necroptosis, epigenetic regulation and other apparent metabolic pathways.