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SIV diagnostic trends

The Zoetis SIV Surveillance Team works closely with universities and veterinary diagnostic laboratories to evaluate which strains are impacting the industry now and those that may become problematic in the future. Below are diagnostic trends in SIV.

Alpha H1 viruses (can contain H1N1 and H1N2 viruses)1,2

  • Little change for 68 years until 1998
  • Now only occasionally isolated in U.S. pigs

Beta H1 viruses (can contain H1N1 and H1N2 viruses)1,2

  • First diagnosed in 2001
  • Currently not as common

Gamma H1 viruses (can contain H1N1 and H1N2 viruses)1,2

  • First diagnosed in 2000
  • Remains active

Delta H1 Viruses (can contain H1N1 and H1N2 viruses)3,4

  • First diagnosed in 2003
  • In 2008, diversity found and subclusters are identified5-8
  • Delta 1 and Delta 2 are actively circulating

Pandemic H1N1

  • First diagnosed in 2009
  • Commonly diagnosed

Cluster IV H3N2

  • Circulating for last several years
  • Other H3N2 clusters are rarely diagnosed

References:
1. Gramer M, Nitzel G, Wicklund E, et al. 2008. Serologic cross-reactions between reference strains and field isolates representing different clusters of H1N1 and H3N2 swine influenza virus. Proceed 39th AASV, p 99-101.
2. Rapp-Gabrielson V, Gramer M, Nitzel G, et al. 2008. Serologic cross-reactivity between reference strains and field isolates representing different genetic clusters of H1N1 and H3N2 swine influenza virus. Proceed 20th IPVS, p.24.
3. Gramer M. 2006. Reassortant human/swine H1N1 and H1N2 swine influenza virus infections in US swine. Proceedings 37th AASV, p 463-64.
4. Karasin A, Carman S, Olsen CW. 2006. Identification of human H1N2 and human-swine reassortant H1N2 and H1N1 influenza A viruses among pigs in Ontario, Canada (2003-2005). J Clin Microbiol. 44:1123-26.
5. Vincent A.L., W. Ma, K.M. Lager, M.R. Gramer, J.A. Richt, B.H. Janke. 2009. Characterization of a newly emerged genetic cluster of H1N1 and H1N2 swine influenza virus in the United States. Virus Genes. 39:176-185.
6. Vincent, A.L., M.L. Harland, A. Lorusso, et al. 2010. Genetic and antigenic characterization of 2008 swine influenza viruses from the United States. Proceed. 21st IPVS, p.259.
7. Rapp-Gabrielson V, Nitzel G, Yonkers T, et al. 2010. Antigenic and genetic variations of endemic human-like (delta cluster) swine influenza H1N1 and H1N2 field isolates from the United States. Proceed. 41st AASV, p 377-78.
8. Rapp-Gabrielson V, Evan J, Czach J, et al. 2010. Antigenic and genetic diversity of delta cluster swine influenza virus H1N1 and H1N2 field isolates from the United States. Proceed 21st IPVS, p.258.