Interspecies human-to-swine IAV transmission occurs globally and contributes to increased IAV diversity in pig populations. We present data that a swine isolate from a 2018-2019 human-to-swine transmission event was shed for multiple days in challenged and contact pigs. By characterizing this introduction through bioinformatic, molecular, and animal experimental approaches, these findings better inform animal health practices and in vaccine decision-making. Since wholly human seasonal H3N2 viruses in the U.S. were not previously identified as being transmissible in pigs (i.e. reverse zoonosis), these findings reveal the interspecies barriers for transmission to pigs may not require significant changes to all human seasonal H3N2.

Interspecies human-to-swine IAV transmission occurs globally and contributes to increased IAV diversity in pig populations. We present data that a swine isolate from a 2018-2019 human-to-swine transmission event was shed for multiple days in challenged and contact pigs. By characterizing this introduction through bioinformatic, molecular, and animal experimental approaches, these findings better inform animal health practices and in vaccine decision-making. Since wholly human seasonal H3N2 viruses in the U.S. were not previously identified as being transmissible in pigs (i.e. reverse zoonosis), these findings reveal the interspecies barriers for transmission to pigs may not require significant changes to all human seasonal H3N2.