Novel reassortant human-like H3N2 and H3N1 influenza A viruses detected in pigs are virulent and antigenically distinct from endemic viruses

摘要

Swine are important hosts in the evolution of influenza A viruses (IAV) because they can become infected with viruses from multiple species.1 Although it is relatively uncommon for a swine lineage virus to become established in humans, spillover of human seasonal viruses to pigs has largely contributed to the great diversity of IAV circulating in swine populations through the maintenance of human-origin viral segments. Since 2012, novel H3 viruses with the hemagglutinin (HA) from contemporary human seasonal viruses were identified through the United States Department of Agriculture (USDA) swine influenza A virus surveillance system. Here, we characterized two of these novel swine human-like H3N2 and H3N1 viruses and compared their pathogenicity andtransmission in pigs to a human H3N2 with common HA ancestry. In a follow up study, we evaluated the role of gene segments on their pathogenesis using reverse genetics-generated reassortants between the swine human-like H3N1 and the seasonal human H3N2.