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Author Notes:

Email Address: Won-Bo Wang : wbwang@ntu.edu.tw

Conceived and designed the experiments: CCK WBW. Performed the experiments: YTL HYK CCL CYL.

Analyzed the data: YTL HYK CCL. Contributed reagents/materials/analysis tools: CLK WBW.

Wrote the paper: YTL CCK WBW. Paper review and discussion: CY.

The authors would like to express our sincere gratitude to Ms. Hsiu-Ping Lin, Mr. Ming-Der Liu, Mr. Tiger Zheng-Rong Li, Mr. Kuan-Yin Chu and several part-time assistants for their effort in field specimen collection.

In addition, the microscope kindly provided by Dr. Kun-Hsien Tsai; scientific discussion and suggestions offered by Dr. Sui-Yuan Chang, Dr. Ming-Fu Chang, Dr. Ming-Tsan Liu, Dr. Chin-Ho Wang, Dr. Shin-Ru Shih and Dr. Shih-Shun Lin are highly appreciated.

We sincerely thank all administrative assistance offered by Ms. Chin-Yi Chen, Ms. Wen-Wen Wang and Mr. Yun-Cheng Chang at the National Taiwan University, Ms. Tanya J. Cassingham [Deputy Director at the Emory-University of Georgia at Athens (UGA) Center of Excellence for Influenza Research and Surveillance (Emory-UGA CEIRS)—Influenza Pathogenesis and Immunology Research Center (IPIRC)] and Dr. Abdul M Jabbar at the Emory Vaccine Center.

We also greatly appreciate Dr. Robert Webster’s long-term guidance in surveillance of avian influenza viruses, Dr. Yi Guan at University of Hong Kong for his discussion in viral evolution studies.

Dr. Diane J. Post at Influenza Project Office, NIH in the U.S. for her effort in organizing influenza surveillance meetings for scientists to discuss important issues and collaboration, Dr. Walter Orenstein (a PI, Emory-UGA CEIRS, Professor, Division of Infectious Diseases; Associate Director, Emory Vaccine Center, Emory University) for his leadership on influenza team research.

Dr. Richard Compans (a Co-PI, Emory-UGA CEIRS, Professor, Dept. of Microbiology & Immunology, Emory University) for his critical review of this manuscript and Mr. Kent M. Suárez, Ms. Melody Wang, Ms. Tanya J. Cassingham, Mr. Jonathan Kao, and Mr. Elias F. Onyoh for their efforts in English editing.


Research Funding:

We would like to thank the National Institutes of Health (NIH) in the United States [NIAID contract grant for Center of Excellence for Influenza Research and Surveillance (CEIRS): HHSN266200700006C] and the National Science Council (NSC) in Taiwan [NSC Grant #102-2621-M-002-002] for financial support of virological surveillance and characterization conducted in this study.

Phenotypic and Genetic Characterization of Avian Influenza H5N2 Viruses with Intra- and Inter-Duck Variations in Taiwan.

Journal Title:



Volume 10, Number 8


, Pages e0133910-e0133910

Type of Work:

Article | Final Publisher PDF


BACKGROUND: Human infections with avian influenza viruses (AIVs) have frequently raised global concerns of emerging, interspecies-transmissible viruses with pandemic potential. Waterfowl, the predominant reservoir of influenza viruses in nature, harbor precursors of different genetic lineages that have contributed to novel pandemic influenza viruses in the past. METHODS: Two duck influenza H5N2 viruses, DV518 and DV413, isolated through virological surveillance at a live-poultry market in Taiwan, showed phylogenetic relatedness but exhibited different replication capabilities in mammalian Madin-Darby Canine Kidney (MDCK) cells. This study characterizes the replication properties of the two duck H5N2 viruses and the determinants involved. RESULTS: The DV518 virus replicated more efficiently than DV413 in both MDCK and chicken DF1 cells. Interestingly, the infection of MDCK cells by DV518 formed heterogeneous plaques with great differences in size [large (L) and small (S)], and the two viral strains (p518-L and p518-S) obtained from plaque purification exhibited distinguishable replication kinetics in MDCK cells. Nonetheless, both plaque-purified DV518 strains still maintained their growth advantages over the plaque-purified p413 strain. Moreover, three amino acid substitutions in PA (P224S), PB2 (E72D), and M1 (A128T) were identified in intra-duck variations (p518-L vs p518-S), whereas other changes in HA (N170D), NA (I56T), and NP (Y289H) were present in inter-duck variations (DV518 vs DV413). Both p518-L and p518-S strains had the N170D substitution in HA, which might be related to their greater binding to MDCK cells. Additionally, polymerase activity assays on 293T cells demonstrated the role of vRNP in modulating the replication capability of the duck p518-L viruses in mammalian cells. CONCLUSION: These results demonstrate that intra-host phenotypic variation occurs even within an individual duck. In view of recent human infections by low pathogenic AIVs, this study suggests possible determinants involved in the stepwise selection of virus variants from the duck influenza virus population which may facilitate inter-species transmission.

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© 2015 Li et al.

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