ABSTRACT
To clarify the epidemiology of influenza A viruses in coordinated swine production systems to which no animals from outside the system are introduced, we conducted virologic surveillance during September 2012–September 2013. Animal age, geographic location, and farm type were found to affect the prevalence of these viruses.
Influenza A viruses (IAVs) are the etiologic agents of acute respiratory disease in many mammalian species. Although originating in wild aquatic birds, IAVs have been successful in crossing the species barrier, and specific subtypes have become endemic among humans and domestic swine populations (1). In the United States, influenza was first described in swine herds during the 1918 pandemic and has circulated among domestic pigs for nearly a century (2). The ability of swine IAVs to infect humans and cause pandemics such as that of the influenza A(H1N1) virus observed during 2009 (3,4) and the sporadic transmission of various swine influenza viruses, including H1N1 (5), H3N2 (6), and variant H3N2 (7), are public health concerns and highlight the need for increased vigilance and understanding of IAV epidemiology among swine.
Here we report the results from 13-months of active surveillance of IAV in coordinated swine production systems in the United States. The objectives of this study were 1) to determine the prevalence of IAV within farms in a closed production system and 2) to determine which sampled population is most affected by IAV.
Kaplan, B, DeBeauchamp, J Crumpton, J, Stigger-Rosser, E Darnell, D, Franks, J, Turner, J, Jeevan, T, Kayali, G, Harding, A, Webby, R, Lowe, J. Surveillance of influenza virus in four coordinated swine production systems, USA. Emerg Infect Dis. (In review)