Global Prevalence and Hemagglutinin Evolution of H7N9 Avian Influenza Viruses from 2013 to 2022

Abstract

H7N9 avian influenza viruses have caused severe harm to the global aquaculture industry and human health. For further understanding of the characteristics of prevalence and hemagglutinin evolution of H7N9 avian influenza viruses, we generated the global epidemic map of H7N9 viruses from 2013 to 2022, constructed a phylogenetic tree, predicted the glycosylation sites and compared the selection pressure of the hemagglutinin. The results showed that although H7N9 avian influenza appeared sporadically in other regions worldwide, China had concentrated outbreaks from 2013 to 2017. The hemagglutinin genes were classified into six distinct lineages: A, B, C, D, E and F. After 2019, H7N9 viruses from the lineages B, E and F persisted, with the lineage B being the dominant. The hemagglutinin of highly pathogenic viruses in the B lineage has an additional predicted glycosylation site, which may account for their persistent pandemic, and is under more positive selection pressure. The most recent ancestor of the H7N9 avian influenza viruses originated in September 1991. The continuous evolution of hemagglutinin has led to an increase in virus pathogenicity in both poultry and humans, and sustained human-to-human transmission. This study provides a theoretical basis for better prediction and control of H7N9 avian influenza.

Function and therapeutic prospects of next-generation probiotic Akkermansia muciniphila in infectious diseases

“…According to the statistical data of World Health Organization, seasonal influenza epidemics cause an estimated 3 to 5 million cases of severe cases worldwide, resulting in approximately 500,000 deaths, and causing significant economic losses and social burdens ( Eichberg et al, 2022 ). H7N9 influenza virus, an emerging zoonotic pathogen, has led to 1, 564 laboratory-confirmed cases of human infection from its initial outbreak until October 2017, and there are still sporadic infections now ( Liu et al, 2023 ). Hu et al reported that A. muciniphila improved host defense against influenza virus H7N9 infection ( Hu et al, 2021 ).…”