For the contribution in preparing cDNA for the PCR template used in this work, Chang-Chun David Lee is added as coauthor in the author line. The a ffi liation of Chang-Chun David Lee is Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, 10055 Taiwan. An additional a ffi liation for Yu-Hsuan Lai is Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10617 Taiwan. The corrected author line is as follows: Chun-Ching Lee, Yu-Chieh Liao, Yu-Hsuan Lai, Chang-Chun David Lee, and Min-Chieh Chuang. The following statement is added in Acknowledgments: We greatly appreciate the study material, the cDNA of avian in fl uenza viruses, kindly provided by Professor Chwan-Chuen King (The Epidemiology of Infectious Disease Laboratory, College of Public Health, National Taiwan University) and Professor Ja-an Annie Ho (Department of Biochemical Science and Technology, National Taiwan University).