Influenza outbreak causes reduction in semen quality of boars

An influenza outbreak occurred at Purdue University’s swine barn, resulting in infection of 28 boars with influenza A virus (H3N2) and causing the death of two boars. The 28 boars, approximately 35 weeks of age, were enrolled in a study at the time of the outbreak and the case report herein describes the effects of the unintended influenza outbreak on sperm production. Semen was collected from the boars once a week and evaluated for total sperm production and concentration, semen volume, and relative motility. Compared to previous collections, total sperm production was substantially decreased (26% reduction) approximately 4 weeks after the first observed clinical signs and remained low for 6 subsequent weeks. Semen production then returned to pre-outbreak levels and was maintained for the duration of the observation period. Sperm motility and percent normal sperm production were also slightly reduced 2 weeks after infection.