Transmission of Human Influenza A Virus in Pigs Selects for Adaptive Mutations on the HA Gene
Jong-Suk Mo, Eugenio J. Abente, Matías Cárdenas, Troy C. Sutton, Brianna Cowan, Lucas M. Ferreri, Ginger Geiger, Phillip C. Gauger, Daniel R. Pérez, Amy L. Vincent Baker, Daniela S. Rajão
Abstract
Influenza A viruses cause respiratory disease in several species, including humans and pigs. The bidirectional transmission of FLUAV between humans and pigs plays a significant role in the generation of novel viral strains, greatly impacting viral epidemiology. However, little is known about the evolutionary processes that allow human FLUAV to become established in pigs. In this study, we generated reassortant viruses containing human seasonal HA and neuraminidase (NA) on different constellations of internal genes and tested their ability to replicate and transmit in pigs. We demonstrated that a virus containing a common internal gene constellation currently found in U.S. swine was able to transmit efficiently via the respiratory route. We identified a specific amino acid substitution that was fixed in the respiratory contact pigs that was associated with improved replication in primary swine tracheal epithelial cells, suggesting it was crucial for the transmissibility of the human virus in pigs.