Reassortment and interspecies transmission of North American H6N2 influenza viruses.

H6N2 influenza viruses were isolated from California chickens in 2000 and 2001. Here we report the characterization of these H6N2 viruses, one of the few descriptions of non-H5, non-H7 subtype influenza viruses in this host. The H6N2 viruses were nonpathogenic in experimentally infected chickens and could be divided into three genotypes. All three genotypes of virus had similar surface glycoproteins and all contained an 18 amino acid deletion in the neuraminidase, a characteristic of other chicken influenza viruses. Differences were apparent, however, in the complement of replicative protein genes between the genotypes. The presence of multiple H6N2 genotypes suggests that independent transmission and/or reassortment events may have taken place between aquatic bird and chicken influenza viruses.