T he circulation of the highly pathogenic H5N1 avian influenza (AI) strain throughout Asia since late 2003 (1) , and more recently in Europe and Africa, has resulted in considerable concern for the potential of a new pandemic. In Cambodia, outbreaks of HPAI A/H5N1 infection were first reported in poultry in early 2004 (2) . Since 2005, 6 human cases have occurred (100% fatal); the 2 most recent cases occurred in early 2006 (3, 4) .