Flu :: Novel H3N1 Swine Influenza Virus Identified in Pigs in Korea

For the first time, researchers from the U.S. and abroad have identified the H3N1 swine influenza virus in domestic pigs in Korea. They report their findings in the November 2006 issue of the Journal of Clinical Microbiology.

A highly infectious respiratory pathogen, the H3N1 influenza A virus is a new genetic reassortment of influenza viruses first identified in pigs in the U.S. in 2004. The virus can be found in birds and mammals (including humans and pigs), but is not generally transmissible between birds and humans. Pigs are believed to be susceptible to both origins resulting in them being deemed “mixing vessels” for the virus and ultimately reinforcing concerns of zoonosis and pandemic outbreaks.

In March and April of 2006 researchers isolated H3N1 influenza A viruses in pigs with respiratory diseases at two commercial swine farms in Korea. Further testing confirmed the H3N1 viruses presenting were reassortments of an H3 human-like virus and other genes from swine influenza viruses and that pig-to-pig and farm-to-farm transmission had occurred. Additionally, analysis of experimentally infected mice suggested the potential to transmit the virus between pigs and other mammalian hosts.

“We report here the first isolation and characterization of H3N1 swine influenza viruses from pigs with respiratory disease in Korea,” say the researchers. “Given the evidence that pigs can support the reassortment of influenza viruses from humans and other species, it is prudent that we enhance surveillance for atypical influenza viruses in pigs as part of overall pandemic preparedness efforts.”

(J.Y. Shin, M.S. Song, E.H. Lee, Y.M. Lee, S.Y. Kim, H.K. Kim, J.K. Choi, C.J. Kim, R.J. Webby, Y.K. Choi. 2006. Isolation and characterization of novel H3N1 swine influenza viruses from pigs with respiratory diseases in Korea. Journal of Clinical Microbiology, 44. 11: 3923-3927.)