Knowledge Bank

Swine infected with influenza A virus (IAV) pose a threat to public health, particularly at the human- animal interface. Over 480 cases of youth infected with swine-lineage IAV associated with agricultural fairs have been reported over the past decade. To this end, nasal samples from 600 exhibition swine and 60 youth exhibitors were collected at The Exposition Swine Show in Indiana, 2021 to estimate the prevalence of IAV in both hosts. Based on historical data collected from this show, it is hypothesized that the estimated IAV prevalence in exhibition swine will be 30.4% and the estimated prevalence of IAV in youth will be less than 1%. Molecular testing revealed 11% of the swine were infected with influenza, with H3N2 being the dominant subtype. Statistical analysis revealed that the estimated IAV prevalence in exhibition swine this year is significantly different than the average estimated IAV prevalence for this show over the past five years, thus, our hypothesis was not supported. Active influenza infections were not detected in youth; however, surveillance needs to be continued at this important interface to gain understanding in IAV transmission across the species barrier.