Evaluation of internal farm biosecurity measures combined with sow vaccination to prevent influenza A virus infection in groups of due-to-wean pigs.

BACKGROUND: Influenza A virus (IAV) is an important respiratory pathogen of pigs that affects pig health, well-being and productivity, has zoonotic potential, and has significant economic impact for producers. The ultimate goal is to maintain herds free from IAV. Due to the probability of IAV introduction into the herds, it is also desirable for herds to have some immunity to the virus. In this study, we evaluated a protocol that combined sow vaccination with the implementation of internal biosecurity practices during the pre-weaning period with the goal to wean IAV negative pigs. Five IAV positive breeding herds were vaccinated twice, 3 weeks apart with a herd-specific autogenous vaccine. For the subsequent 8 weeks, a biosecurity protocol was maintained, consisting of no pig movements after 3 days of age, no use of nurse sows, workers changing disposable gloves between litters, workers not stepping into farrowing crates, and daily disinfection of tools and materials used to handle pigs. RESULTS: Following these interventions, four of the five treatment farms had significant reductions in IAV detection (p value < 0.05). Three of the farms tested negative at all sampling points post-intervention and one farm had a 21% reduction in IAV positivity. CONCLUSIONS: This study indicates that a protocol that combines sow vaccination and enhanced biosecurity practices may limit IAV transmission among piglets and enable the weaning of groups of pigs free from the virus.

Duration of Mycoplasma hyopneumoniae detection in pigs following purposeful aerosol exposure.

Swine disease elimination programs for Mycoplasma hyopneumoniae are commonly applied in the North American swine industry and may include the aerosolization of medium containing lung tissue to achieve population exposure prior to start. Field data has indicated M. hyopneumoniae PCR detection in pigs beyond 240 days post-herd closure (dphc; planned end of an elimination program) and is thought to contribute to disease elimination programs' failure. Here, the duration of M. hyopneumoniae detection in sows and replacement gilts following aerosolized lung homogenate exposure, as part of a dual disease elimination program, was determined. A subset of sows and gilts from a commercial sow herd and off-site gilt development unit were longitudinally sampled to collect deep tracheal catheter secretions at various times post-exposure. Samples were tested for M. hyopneumoniae using a species-specific real-time PCR. A proportion of 58, 51, 52, 19, and 2% females were detected positive at 30, 60, 120, 180 and 240 dphc, respectively. Noteworthy, a greater proportion of gilts exposed at the off-site GDU were detected PCR positive for M. hyopneumoniae at each sampling event, compared to sows. In this study, assaying for genetic material in live female pigs showed extended detection of M. hyopneumoniae until at least 240 dphc. This data suggests persistence of M. hyopneumoniae longer than previously reported and highlights the importance of performing diagnostic testing to confirm negativity to the bacterium, prior to opening sow herds, especially late in the herd closure timeline.