This article is a US Government work and, as such, is in the public domain in the United States of America.
Molecular changes associated with the transmission of avian influenza a H5N1 and H9N2 viruses to humans*
Article first published online: 29 NOV 2001
Published 2002 Wiley-Liss, Inc.
Journal of Medical Virology
Volume 66, Issue 1, pages 107–114, January 2002
How to Cite
Shaw, M., Cooper, L., Xu, X., Thompson, W., Krauss, S., Guan, Y., Zhou, N., Klimov, A., Cox, N., Webster, R., Lim, W., Shortridge, K. and Subbarao, K. (2002), Molecular changes associated with the transmission of avian influenza a H5N1 and H9N2 viruses to humans. J. Med. Virol., 66: 107–114. doi: 10.1002/jmv.2118
- Issue published online: 29 NOV 2001
- Article first published online: 29 NOV 2001
- Manuscript Accepted: 14 MAY 2001
- National Institute of Allergy and Infectious Diseases. Grant Number: Public Health Research Contract AI95357
- Cancer Center Support. Grant Number: CORE CA-21765
- American Lebanese Associated Charities
- avian influenza virus;
- interspecies transmission;
- host range
In order to identify molecular changes associated with the transmission of avian influenza A H5N1 and H9N2 viruses to humans, the internal genes from these viruses were compared to sequences from other avian and human influenza A isolates. Phylogenetically, each of the internal genes of all sixteen of the human H5N1 and both of the H9N2 isolates were closely related to one another and fell into a distinct clade separate from clades formed by the same genes of other avian and human viruses. All six internal genes were most closely related to those of avian isolates circulating in Asia, indicating that reassortment with human strains had not occurred for any of these 18 isolates. Amino acids previously identified as host-specific residues were predominantly avian in the human isolates although most of the proteins also contained residues observed previously only in sequences of human influenza viruses. For the majority of the nonglycoprotein genes, three distinct subgroups could be distinguished on bootstrap analyses of the nucleotide sequences, suggesting multiple introductions of avian virus strains capable of infecting humans. The shared nonglycoprotein gene constellations of the human H5N1 and H9N2 isolates and their detection in avian isolates only since 1997 when the first human infections were detected suggest that this particular gene combination may confer the ability to infect humans and cause disease. J. Med. Virol. 66:107–114, 2002. Published 2002 Wiley-Liss, Inc.