Farm management practices associated with influenza A virus contamination of people working in Midwestern United States swine farms.

Indirect transmission of influenza A virus (IAV) contributes to virus spread in pigs. To identify farm management activities with the ability to contaminate farmworkers' hands and clothing that then could be a source of virus spread to other pigs, we conducted a within-farm, prospective IAV surveillance study. Hands and clothes from farmworkers performing the activities of piglet processing, vaccination, or weaning were sampled before and after the activities were performed.

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.

Evaluation of dam parity and internal biosecurity practices in influenza infections in piglets prior to weaning.

Influenza is an important respiratory disease of pigs and humans. Controlling influenza in pigs is challenging due to the substantial genetic diversity of influenza A virus (IAV). In this study, we assessed the impact of internal biosecurity practices directed at limiting exposure of piglets to IAV before weaning; evaluated the association of sow parity with IAV prevalence in piglets and the levels of maternally derived antibodies (MDA), and documented the frequency of detection of IAV on farmworkers' hands and the instruments used when handling pigs.

Evidence of influenza A infection and risk of transmission between pigs and farmworkers.

Interspecies transmission of influenza A virus (IAV) between pigs and people represents a threat to both animal and public health. To better understand the risks of influenza transmission at the human-animal interface, we evaluated 1) the rate of IAV detection in swine farmworkers before and after work during two human influenza seasons, 2) assessed risk factors associated with IAV detection in farmworkers and 3) characterized the genetic sequences of IAV detected in both workers and pigs. Of 58 workers providing nasal passage samples during 8-week periods during the 2017/18 and 2018/19 influenza seasons, 33 (57%) tested positive by rRT-PCR at least once.

Effect of pooling udder skin wipes on the detection of influenza A virus in preweaning pigs.

Influenza A virus (IAV) active surveillance in pigs prior to weaning is commonly conducted by collecting individual samples, mostly nasal swabs. Recently, the use of udder skin wipes collected from lactating sows was identified as an effective sampling method to indicate IAV status of suckling piglets prior to weaning. However, there is limited information on the effect of pooling multiple udder wipes on the ability to detect IAV.

Shedding and transmission of a live attenuated influenza A virus vaccine in pre-weaned pigs under field conditions.

Influenza A virus (IAV) is one of the most important respiratory viruses affecting pig health and vaccination is the most common strategy to control influenza infections. In this field study we assessed the onset and duration of shedding of a live attenuated influenza virus (LAIV) vaccine, its ability to transmit to non-vaccinated pigs and whether the LAIV could be aerosolized and detected in the environment. Thirty-three litters (n = 33) of a farm using the LAIV vaccine were selected for the study, a subset of them (n = 12) were left unvaccinated and a subset of piglets (n = 3) in vaccinated litters were also left unvaccinated to serve as sentinels.