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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Virus and Prion Research » Research » Publications at this Location » Publication #215873

Title: Viral Reassortment and Transmission after Coinfection of Pigs with two Swine Influenza Viruses

item Lager, Kelly
item Vincent, Amy
item Richt, Juergen

Submitted to: Conference Research Workers Disease Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 10/30/2007
Publication Date: 12/2/2007
Citation: Ma, W., Lager, K.M., Fleckenstein, E.S., Lekcharoensuk, P., Janke, B.H., Vincent, A.L., Webby, R.J., Richt, J.A. 2007. Viral reassortment and transmission after coinfection of pigs with 2 swine influenza viruses [abstract]. Conference of Research Workers in Animal Diseases Annual Meeting. Paper No. 146. p. 147.

Interpretive Summary:

Technical Abstract: Influenza A viruses of subtypes H3N2, H1N1 and H1N2 are circulating in U.S. swine. Because influenza A virus contains 8 RNA segments, genetic reassortment can take place when 2 or more influenza viruses infect the same cell. We studied the reassortment potential and transmissibility of swine influenza viruses (SIVs) by coinfecting 6 pigs with classical H1N1 IA/30 and triple reassortant H3N2 TX/98 SIVs. On day 3 post infection, 8 contact pigs were introduced to the primary challenge group. On day 7, the first contact group was exposed to a second group of contact pigs. Throughout the experiment, nasal swabs and at necropsy bronchoalveolar lavage fluids (BALFs) were collected. Individual viruses were isolated from swabs and BALFs using plaque assay. RT-PCR was performed to amplify all 8 segments of each virus followed by digestion with selected restriction enzymes. A unique restriction enzyme site introduced into each segment of the H1N1 IA/30 SIV made it possible to distinguish between the individual gene segments of H1N1 IA/30 and H3N2 TX/98. A total of 180 viruses from nasal swabs and BALFs out of all experimental groups were molecularly characterized. Although a variety of reassortant viruses were found in the lungs of the 6 primary infection pigs, only 1 virus, the original H3N2 TX/98, was transmitted between pigs. These data indicate this virus was more efficient in transmission when compared to the classical H1N1 SIV and the reassortant H1N1, H3N1, H3N2, and H1N2 viruses found in the lungs of the coinfected pigs.