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United States Department of Agriculture

Agricultural Research Service

Research Project: SWINE VIRAL DISEASES PATHOGENESIS AND IMMUNOLOGY Title: Experimental Inoculation of Pigs with Pandemic H1N1 2009 Virus and HI Cross-Reactivity with Contemporary Swine Influenza Virus Antisera

Authors
item Vincent, Amy
item Lager, Kelly
item Faaberg, Kay
item Harland, Michelle
item Zanella, Eraldo -
item Zanella, Janice -
item Kehrli Jr, Marcus
item Janke, Bruce -
item Klimov, Alexander -

Submitted to: Influenza and Other Respiratory Viruses
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 2, 2009
Publication Date: January 13, 2009
Citation: Vincent, A.L., Lager, K.M., Faaberg, K.S., Harland, M., Zanella, E.L., Zanella, J.R., Kehrli, Jr., M.E., Janke, B.H., Klimov, A. 2009. Experimental Inoculation of Pigs with Pandemic H1N1 2009 Virus and HI Cross-Reactivity with Contemporary Swine Influenza Virus Antisera. Influenza and Other Respiratory Viruses. 4(2):53-60.

Interpretive Summary: In March-April 2009, a novel A/H1N1 influenza virus emerged in the human population in North America. The genetic makeup of the virus was demonstrated to be a combination from swine influenza A viruses (SIV) of North American and Eurasian lineages that had never before been identified in swine or other species. Here we describe the experimental infection of weaned pigs with the pandemic A/CA/04/2009 (H1N1)v. All infected pigs became ill with clinical signs and lung lesions similar to those induced by endemic SIV. Virus was only isolated from the respiratory tract, but not in blood or muscle. These results indicate that A/H1N1 infection in pigs is not a food safety risk to consumers. In addition, the serologic cross-reactivity of a panel of U.S. SIV H1N1 or H1N2 anti-sera was tested with three human isolates of pandemic A/H1N1. Serologic cross-reactivity was limited with A/CA/04/2009 (H1N1)v. In contrast, cross-reactivity was moderate with A/Mexico/4108/2009 (H1N1)v, most notably among virus anti-sera from viruses with genetically related hemagglutinin genes. Anti-sera from pigs vaccinated with North American SIV vaccines were evaluated against the A/H1N1 viruses and only weak cross-reactivity was detected among a few of the vaccine anti-sera. The limited cross-reactivity suggests North American pigs may not be fully protected from infection with A/H1N1 from previous exposure or vaccination.

Technical Abstract: In March-April 2009, a novel A/H1N1 emerged in the human population in North America. The gene constellation of the virus was demonstrated to be a combination from swine influenza A viruses (SIV) of North American and Eurasian lineages that had never before been identified in swine or other species. Here we describe the experimental infection of weaned pigs with A/CA/04/2009 H1N1 and the serologic cross-reactivity of a panel of U.S. SIV H1N1 or H1N2 anti-sera with three human isolates of A/H1N1. All infected pigs demonstrated clinical signs and lesions similar to those induced by endemic SIV. Viable virus and antigen were only isolated from or identified in the respiratory tract. Serologic cross-reactivity was limited with A/CA/04/2009 A/H1N1. In contrast, cross-reactivity was moderate with A/Mexico/4108/2009 H1N1, most notably among virus anti-sera from the same H1 phylogenetic cluster. Anti-sera from pigs vaccinated with North American SIV vaccines were evaluated against the A/H1N1 and only weak cross-reactivity was detected among a few of the vaccine anti-sera. The limited cross-reactivity suggests North American pigs may not be fully protected from infection with A/H1N1 from previous exposure or vaccination.

Last Modified: 11/28/2014
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