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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Virus and Prion Research » Research » Publications at this Location » Publication #297520

Title: Detection and characterization of influenza A virus endemic circulation in neonatal and nursery pigs in a farm using an inactivated influenza vaccine

item GAUGER, P - Iowa State University
item DIAS, A - University Of Minas Gerais
item Baker, Amy
item BAKER, R - Iowa State University
item ZHANG, J - Iowa State University
item Kitikoon, Pravina

Submitted to: American Association of Swine Veterinarians Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 12/8/2013
Publication Date: 3/1/2014
Citation: Gauger, P.C., Dias, A.S., Vincent, A.L., Baker, R.B., Zhang, J., Kitikoon, P. 2014. Detection and characterization of influenza A virus endemic circulation in neonatal and nursery pigs in a farm using an inactivated influenza vaccine. Proceedings of the 45th American Association of Swine Veterinarians Annual Meeting. p. 51-54.

Interpretive Summary:

Technical Abstract: Influenza A virus (IAV) is the cause of an acute respiratory disease affecting swine worldwide with potential zoonotic implications. Inactivated IAV vaccines used in breeding females provides passive immunity to neonatal piglets through colostrum. However, maternally derived antibody (MDA) may reduce clinical disease but not infection of susceptible piglets (2). Endemic circulation of IAV in breeding herds may be due to re-infection of neonatal swine with inadequate levels and/or types of passive immunity, non-protective maternal antibodies or due to the introduction of a novel IAV (1). Infected, but non-clinical, neonatal swine may be responsible for the transmission of IAV to additional piglets as MDA declines during the pre- and post-weaning phase of production. The objectives of this study were to: 1) evaluate the prevalence of IAV infection in neonatal swine on a farm using influenza vaccination in breeding females; 2) determine the IAV subtype(s) present in neonatal and nursery pigs in the same production system; 3) determine the presence of MDA in neonatal piglets; 4) compare the genetic relationship of IAV’s isolated from neonatal and nursery pig populations and their antigenic relationship with the vaccine antigens used in the sow herd. Four breeding farms from the same production system located in the Midwest United States using IAV vaccination in the breeding herd were selected for the study. Samples included 4,320 nasal swabs and serum from 12-17 day old piglets within the same litter collected every-other-week between March-May and July-August 2013 for a total of eight collections. Serum was also collected from 256 breeding females corresponding with the litters. Eight oral fluid samples were collected from the same group of piglets after transport to the nursery at approximately four weeks of age. Serum samples will be evaluated for nucleoprotein (NP) antibody by ELISA representing MDA in piglets. Nasal swabs and oral fluids will be evaluated for the presence of IAV by a screening and subtyping PCR and hemagglutinin nucleotide sequences will be compared between IAV isolates from their corresponding groups. Serum from breeding females will be used to detect the presence of IAV NP antibody and for hemagglutination inhibition (HI) tests against vaccine antigens and IAV recovered from neonatal and nursery piglets. Preliminary results from March through May 10th have demonstrated approximately 88.7% of the piglets (N=2,700) with NP antibodies in serum. In addition, 70% of the litters (N=143) demonstrated MDA in all piglets within the litter in contrast to 30% of the litters that exhibited at least one pig without detectable MDA and 3.5% of the litters where all pigs in the litter were negative for IAV antibody. Additional laboratory testing is in progress and will be reported upon completion of laboratory analysis. This study will report for the first time the presence of passively transferred antibody using an NP ELISA in neonatal piglets and the prevalence of IAV endemic circulation in swine farms using inactivated vaccines to prevent IAV-associated reproductive disease and infection. In addition, this study will also demonstrate the genetic relationship between IAV detected in pre- and post-weaned pigs in the nursery. Overall, this study will help guide the management, control and biosecurity measures that may affect the level of influenza circulation on swine breeding farms and provide guidance for using IAV vaccines in swine. References 1.Allerson M, Deen J, Detmer SE, Gramer MR, Joo HS, Romagosa A, Torremorell M. 2013. The impact of maternally derived immunity on influenza A virus transmission in neonatal pig populations. Vaccine 31:500-505. 2. Kitikoon P, Nilubol D, Erickson BJ, Janke BH, Hoover TC, Sornsen SA, Thacker EL. 2006. The immune response and maternal antibody interference to a heterologous H1N1