A/duck/Yunnan/971/2002 A/chicken/Yunnan/1628/2003 A/duck/Yunnan/862/2002 A/duck/Hunan/1340/2002 A/duck/Hunan/378/2003 A/duck/Hunan/300/2003 A/muscovy duck/Vietnam/48/2007 A/muscovy duck/Son-La/07-85/2007 A/duck/Vietnam/NCVD-57/2007 A/duck/Vietnam/NCVD-56/2007 A/muscovy duck/Vietnam/NCVD120/2007 A/muscovy duck/Nam-Dinh/07-87/2007 A/duck/Nam-Dinh/07-88/2007 A/Vietnam/UT31239/2007 A/duck/Vietnam/NCVD-99/2007 A/duck/Vietnam/NCVD-68/07 A/duck/Vietnam/NCVD-64/07 A/duck/Vietnam/NCVD-102/2007 A/duck/Phu-Tho/07-92/2007 A/duck/Ninh-Binh/07-68/2007 A/muscovy duck/Ha-Nam/07-47/2007 A/muscovy duck/Vietnam/NCVD-47/2007 A/muscovy duck/Vietnam/51/2007 A/duck/Vietnam/NCVD-49/07 A/duck/Vietnam/53/2007 A/duck/Nghe-An/07-49/2007 A/duck/Vietnam/NCVD-70/07 A/duck/Vietnam/NCVD-50/07 A/duck/Vietnam/NCVD-63/07 A/muscovy duck/Vietnam/57/2007 A/duck/Vietnam/NCVD-81/07 A/duck/Vietnam/43/2007 A/duck/Vietnam/NCVD-71/07 A/duck/Vietnam/NCVD-53/2007 A/duck/Ha-Tinh/07-53/2007 A/muscovy duck/Ha-Nam/07-84/2007 A/chicken/Ha-Nam/07-83/2007 A/duck/Vietnam/NCVD-65/07 A/muscovy duck/Bac-Gieng/07-66/2007 A/muscovy duck/Vietnam/NCVD-66/2007 A/chicken/Vietnam/NCVD-74/07 A/chicken/Bac-Giang/07-74/2007 A/chicken/Vietnam/NCVD002/2008 A/duck/Vietnam/NCVD-146/08 A/duck/Vietnam/NCVD-159/08 A/Vietnam/UT31413II/2008 A/Owstons civet/Vietnam/NCVD004/2008 A/civet/Vietnam/NCVD-004/2008 A/Vietnam/HN31413/08 A/duck/Vietnam/NCVD-030/2008 A/duck/Vietnam/NCVD-140/08 A/duck/Vietnam/NCVD-145/08 A/muscovy duck/Vietnam/NCVD-156/08 A/muscovy duck/Vietnam/NCVD-154/08 A/duck/Vietnam/NCVD-021/2008 A/Vietnam/UT31312II/2007 A/Vietnam/HN31312/2007 A/Vietnam/HN31242/2007 A/chicken/Vietnam/NCVD029/2008 A/muscovy duck/Vietnam/56/2007 A/duck/Vietnam/55/2007 A/duck/Vietnam/NCVD-76/07 A/duck/Vietnam/NCVD-61/2007 A/duck/Vietnam/NCVD-60/2007 A/duck/Vietnam/NCVD-55/2007 A/duck/Nam-Dinh/07-55/2007 A/duck/Thai-Ninh/07-86/2007 A/chicken/Vietnam/NCVD-138/08 A/duck/Vietnam/NCVD-98/2007 A/duck/Vietnam/NCVD-93/2007 A/Vietnam/UT31244III/2007 A/Vietnam/UT31244II/2007 A/Vietnam/HN31244/07 A/Viet Nam/HN31242/2007 A/duck/Vietnam/NCVD-94/2007 A/duck/Vietnam/NCVD-020/2008 A/chicken/Vietnam/NCVD108/2007 A/duck/Vietnam/NCVD-019/2008 A/duck/Nam-Dinh/07-91/2007 A/duck/Vietnam/50/2007 A/duck/Vietnam/NCVD-100/2007 A/muscovy duck/Vietnam/NCVD101/2007 A/muscovy duck/Vietnam/41/2007 A/duck/Vietnam/NCVD-82/07 A/chicken/Vietnam/NCVD106/2007 A/muscovy duck/Thai-Binh/07-90/2007 A/chicken/Thai-Binh/07-89/2007 A/duck/Vietnam/NCVD-022/2008 A/duck/Vietnam/NCVD-003/2008 A/muscovy duck/Vietnam/NCVD119/2007 A/duck/Vietnam/NCVD-116/2007 A/duck/Vietnam/NCVD-105/2007 A/duck/Vietnam/NCVD-118/2007 A/chicken/Vietnam/033/2008 A/chicken/Vietnam/NCVD025/2008 A/chicken/Vietnam/NCVD-279/2009 A/chicken/Vietnam/NCVD027/2008 A/chicken/Vietnam/NCVD039/2008 A/chicken/Vietnam/NCVD018/2008 A/chicken/Vietnam/NCVD-086/08 A/Vietnam/UT31203A/2007 A/Vietnam/HN31203/I/07 A/muscovy duck/Vietnam/NCVD114/2007 A/duck/Vietnam/NCVD-113/2007 A/Vietnam/HN31388/07 A/duck/Vietnam/NCVD-110/2007 A/muscovy duck/Vietnam/NCVD51/2007 A/muscovy duck/Vietnam/NCVD-51/2007 HA full tree. Neighbor-joining tree of 2,947 H5N1 HA sequences A/muscovy duck/Vietnam/NCVD112/2007 A/duck/Vietnam/NCVD-111/2007 A/avian/Vietnam/NCVD-133/08 A/avian/Vietnam/NCVD-132/08 A/chicken/Vietnam/NCVD-084/08 A/duck/Vietnam/NCVD-014/2008 A/Vietnam/HN31641/2009 constructed using a GTR+I+G model in PAUP* v4.0b10. The tree A/muscovy duck/Vietnam/NCVD041/2008 A/duck/Vietnam/NCVD-024/2008 A/avian/Vietnam/NCVD-124/08 A/chicken/Vietnam/NCVD005/2008 A/chicken/Vietnam/NCVD006/2008 A/duck/Vietnam/NCVD-028/2008 A/duck/Vietnam/NCVD-187/08 A/chicken/Vietnam/NCVD-188/2008 was rooted using A/turkey/England/5092/1991.