Avian Influenza Research Today is a free monthly online journal that collates and summarizes the latest research about Avian Influenza, including details on bird flu, h5n1, risks, vaccines, prevention.

Continuing evolution of H9 influenza viruses in Korean poultry.

Lee YJ, Shin JY, Song MS, Lee YM, Choi JG, Lee EK, Jeong OM, Sung HW, Kim JH, Kwon YK, Kwon JH, Kim CJ, Webby RJ, Webster RG, Choi YK

Avian Disease division, National Veterinary Research and Quarantine Service, 480 Anyang, Anyang city, 430-824, Korea.

We analyzed the evolution of H9 influenza viruses isolated from Korean chicken farms from 2002 to 2004. Korean H9 viruses formed two antigenically distinct groups: those isolated from 1996 to mid-2003, and those isolated from late 2003 through 2004. Most of the 2004 isolates showed greater cross-reactivity with the second group than with the first group. Phylogenetic analysis of the 12 viruses studied revealed three genotypes of H9N2 viruses and showed that reassortment had occurred. One isolate, Ck/Kor/164/04, belonged to the H9N8 subtype. Its HA and PB1 genes were similar to those of the H9N2 viruses, but its other genes were closely related to H3N8 viruses. This report is the first (to our knowledge) of H9N8 infection in this host. The pathogenicity of the early isolates altered due to antigenic drift and reassortment, leading to H9 avian influenza viruses in Korea that potentially can expand their host range to mammalians.

Published 26 February 2007 in Virology, 359(2): 313-23.
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