Characteristics of human cases of highly pathogenic avian influenza H5N1 virus infection reported to WHO from 1997 to 16 March 2010 by country.

AClade(s) isolated from humans. BData from cases up to 1 Jan 2009. Adapted from sources [13], [17], [63], [64], [65], [66], [67]. †Includes data from 2004–2005 cases only; ‡Includes data from 2005–2006 cases only; αIncludes data from 2006–2007 cases only; ‡‡Includes data from 2006 cases only; NR = Not released.