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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Virus and Prion Research » Research » Publications at this Location » Publication #297159
Title: Maternal derived antibodies induce vaccine-associated enhanced respiratory disease in weaned pigs challenged with heterologous virus

Author
item RAJAO, D - Non ARS Employee
item Baker, Amy
item Loving, Crystal
item SANDBULTE, M - Iowa State University
item Kitikoon, Pravina

Submitted to: American Association of Swine Veterinarians Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 9/3/2013
Publication Date: 3/1/2014
Citation: Rajao, D., Vincent, A.L., Loving, C.L., Sandbulte, M., Kitikoon, P. 2014. Maternal derived antibodies induce vaccine-associated enhanced respiratory disease in weaned pigs challenged with heterologous virus. Proceedings of the 45th American Association of Swine Veterinarians Annual Meeting, p.41-47.

Interpretive Summary:

Technical Abstract: Effective vaccine immunization against influenza A viruses (IAV) in pigs in the United States is a challenge because of the great antigenic diversity of co-circulating viruses. Maternally derived antibodies (MDA) interfere with vaccine efficacy and can lead to vaccine-enhanced respiratory disease (VAERD) in pigs vaccinated in the presence of MDA. Our aim was to evaluate if MDA alone interferes with IAV infection, clinical disease, and transmission in weaned non-vaccinated piglets. Sows with existing antibodies to 2009 pandemic H1N1 (H1N1pdm09) were boosted with H1N1pdm09 whole inactivated (WIV) or live attenuated (LAIV) vaccine. At three weeks of age, MDA-positive piglets were challenged with homologous H1N1pdm09 or heterologous delta1-H1N2 virus, along with MDA-negative controls. WIV-MDA piglets with high antibody titers were protected from homologous infection with H1N1pdm09 and did not transmit to contact pigs. LAIV-MDA piglets with high antibody titers were partially protected from homologous challenge with H1N1pdm09, but they transmitted virus to all their indirect contacts. However, this group had less virus shedding than the naïve infected controls. The major finding of this study was that piglets with WIV-derived MDA and challenged with delta1-H1N2 developed VAERD, with more pronounced lung lesions and clinical signs. Two piglets in this group died at 2 days post infection from severe VAERD and respiratory complications. LAIV-derived MDA did not cross-protect piglets against heterologous challenge with delta-H1N2, however it did not result in VAERD. All pigs in indirect contact with the delta1-H1N2 challenged groups were infected, indicating that mismatched MDA does not mitigate viral shedding and transmission. Our data supports that although homologous vaccine-derived MDA can protect piglets against disease, and to some extent against infection, MDA alone can induce VAERD upon heterologous infection.