Volume 14, Number 7—July 2008
Materials Available Online Only
Toward a Unified Nomenclature System for Highly Pathogenic Avian Influenza Virus (H5N1)
||Maintain previously designated clade numbers where possible (i.e., clade 2.2 remains 2.2 and clade 1 remains 1)
|2||New clade designations based on phylogenetic tree topology derived from all available sequences (the large tree)|
|H5N1 progenitors (closest to Gs/Guangdong/1/96) re-designated as clade 0|
|Subsequent clades numbered starting from clade 3 (i.e., clades 3–9)|
|Clades designated by presence of a distinct common node shared by at least 4 isolates (in a monophyletic group)|
| Additional branches designated as a single clade evolves into more than one distinct lineage (i.e., clade 2.2 or clade 2.3.1; based on sharing of a common node and monophyletic grouping)
|3||Average percentage pairwise distances between and within clades (using Kimura 2-parameter)|
|Distinct clades should have >1.5% average distances between other clades|
| Distinct clades should have <1.5% average distances within the clade (may be slightly higher in clades with highly evolved outliers; i.e., Ck/Shanxi/2/2006 in clade 7)
|4||Bootstrap (based on 1,000 neighbor-joining bootstrap replicates) >60% bootstrap value at clade-defining node|
1The working group was established by request of the World Health Organization’s Global Influenza Programme, Department of Epidemic and Pandemic Alert and Response (WHO, GIP, EPR), the World Organisation for Animal Health (OIE), and the Food and Agriculture Organization (FAO). It consisted of the following members: Ruben O. Donis, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, USA (co-chair); Gavin J.D. Smith, University of Hong Kong, Hong Kong Special Administrative Region, People’s Republic of China (co-chair); Michael L. Perdue, WHO, GIP, EPR, Geneva, Switzerland2 (coordinator); Ian H. Brown, Veterinary Laboratories Agency, Addlestone, UK; Hualan Chen, Harbin Veterinary Research Institute, Chinese Academy of Agriculture Sciences CAAS, Harbin, People’s Republic of China; Ron A.M. Fouchier, Erasmus University, Rotterdam, the Netherlands; Yoshihiro Kawaoka, University of Wisconsin-Madison, Madison, Wisconsin, USA, and Institute of Medical Science, University of Tokyo, Tokyo, Japan; John Mackenzie, Curtin University of Technology, Perth, Western Australia, Australia; and Yuelong Shu, China Centers for Disease Control, Bejing, People’s Republic of China. In addition, the following persons made substantial contributions: Ilaria Capua, Instituto Zooprofilattico Sperimentale delle Venezie, Padova, Italy; Nancy Cox, Todd Davis, Rebecca Garten, and Catherine Smith, CDC; Yi Guan and Dhanasekaran Vijaykrishna, University of Hong Kong; Elizabeth Mumford, WHO, GIP, EPR; and Colin A. Russell and Derek Smith, University of Cambridge, Cambridge, UK.
2Current affiliation: US Department of Health and Human Services, Washington, DC, USA.