Evolution and Pathogenicity of the H1 and H3 Subtypes of Swine Influenza Virus in Mice between 2016 and 2019 in China

Pigs are considered a “mixing vessel” that can produce new influenza strains through genetic reassortments, which pose a threat to public health and cause economic losses worldwide. The timely surveillance of the epidemiology of the swine influenza virus is of importance for prophylactic action. In this study, 15 H1N1, one H1N2, and four H3N2 strains were isolated from a total of 4080 nasal swabs which were collected from 20 pig farms in three...