The Origin of Human-infecting Avian Influenza A H6N1 Virus

Summary In this study, we retraced the origin of the reported avian influenza A H6N1 virus infecting a 20-year-old woman in Taiwan. As we know, this is the first reported case of human infection by the H6N1 virus, because this subtype virus usually circulates in birds and poultry. Therefore it is crucial to know how this virus attained the ability to infect humans. Using phylogenetic analysis, we found that this virus was derived from reassortments of multiple lineages of H6N1 viruses and H5N2 viruses. The results deepen our understanding of how the new human-infecting virus originated and based on these we discussed possible explanations for the H6N1 infection of humans. Our results, together with recent studies of H7N9 viruses which result in severe disorders, suggest that reassortments among avian-type viruses are quite often, which may sometimes result in fatal infections in humans. Thus a close watch on the circulation of avian influenza viruses is pretty necessary.