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.

Impact of nurse sows on influenza A virus transmission in pigs under field conditions.

Piglets prior to weaning play a central role in maintaining influenza infections in breeding herds and the use of nurse sows is a common practice to adopt piglets that fall behind and that otherwise would die. Transmission of influenza A virus (IAV) from nurse sows to adopted pigs has been reported experimentally, however, the importance of this route of transmission under field conditions has not yet been elucidated. A cohort study to assess the IAV status in nurse and control sows and their respective litters was carried out in three influenza positive breed-to-wean farms.

Relationship between weaning age and antibiotic usage on pig growth performance and mortality.

A total of 2,184 pigs (DNA 600 × PIC L42) were used to evaluate the effects of weaning age and antibiotic (AB) use on pig performance from weaning to marketing in a commercial production system. Experimental treatments were arranged in a 3 × 2 factorial with main effects of weaning age (18.5, 21.

Effect of influenza A virus sow vaccination on infection in pigs at weaning: A prospective longitudinal study.

Although vaccination is the main measure to control influenza A virus (IAV) in swine, there is limited information on the efficacy of sow vaccination on reducing IAV infections in pigs at weaning. We assessed the effect of sow vaccination on IAV infection in pigs at weaning in a cohort of 52 breeding herds studied prospectively. Herds were voluntarily enrolled according to their IAV history, sow vaccination protocol and monitored during six months (prospective longitudinal study).

Genetic variability of influenza A virus in pigs at weaning in Midwestern United States swine farms.

Suckling piglets play an important role at maintaining influenza A virus (IAV) infections in breeding herds and disseminating them to other farms at weaning. However, the role they play at weaning to support and promote genetic variability of IAV is not fully understood. The objective here was to evaluate the genetic diversity of IAV in pigs at weaning in farms located in the Midwestern USA.