Emergence and Evolution of Avian H5N2 Influenza Viruses in Chickens in Taiwan

• Type of Material: Article
• Authors: Chang-Chun David Lee, National Taiwan University; Huachen Zhu, University of Hong Kong; Pei-Yu Huang, University of Hong Kong; Liuxia Peng, Shantou University; Yun-Cheng Chang, National Taiwan University; Chun-Hung Yip, University of Hong Kong; Yao-Tsun Li, National Taiwan University; Chung-Lam Cheung, University of Hong Kong; Richard Compans, Emory University; Chinglai Yang, Emory University; David K. Smith, University of Hong Kong; Tommy Tsan-Yuk Lam, University of Hong Kong; Chwan-Chuen King, National Taiwan University; Yi Guan, University of Hong Kong
• Language: English
• Date: 2014-05-01
• Publisher: American Society for Microbiology
• Publication Version: Final Published Version
• Copyright Statement: © 2014, American Society for Microbiology.
• Final Published Version (URL): http://dx.doi.org/10.1128/JVI.00139-14
• Title of Journal or Parent Work: Journal of Virology
• ISSN: 0022-538X
• Volume: 88
• Issue: 10
• Start Page: 5677
• End Page: 5686
• Grant/Funding Information: This study was supported by the Li Ka Shing Foundation, the National Institutes of Health (NIAID contracts HHSN266200700005C; and HHSN266200700006C), and the Area of Excellence Scheme of the University Grants Committee (grant AoE/M-12/06) of the Hong Kong SAR Government.
• Keywords: Science & Technology; MULTIPLE GENOTYPES; VIRULENCE; Virology; Life Sciences & Biomedicine; VIROLOGY; CLEAVABILITY; A VIRUS; TRANSMISSION; SOUTHERN CHINA; SEQUENCE; HEMAGGLUTININ CLEAVAGE SITE; CARBOHYDRATE; ESTABLISHMENT
• Research Categories: Health Sciences, Immunology; Health Sciences, Epidemiology; Biology, Virology

Abstract

Sporadic activity by H5N2 influenza viruses has been observed in chickens in Taiwan from 2003 to 2012. The available information suggests that these viruses were generated by reassortment between a Mexican-like H5N2 virus and a local enzootic H6N1 virus. Yet the origin, prevalence, and pathogenicity of these H5N2 viruses have not been fully defined. Following the 2012 highly pathogenic avian influenza (HPAI) outbreaks, surveillance was conducted from December 2012 to July 2013 at a live-poultry wholesale market in Taipei. Our findings showed that H5N2 and H6N1 viruses cocirculated at low levels in chickens in Taiwan. Phylogenetic analyses revealed that all H5N2 viruses had hemagglutinin (HA) and neuraminidase (NA) genes derived from a 1994 Mexican-like virus, while their internal gene complexes were incorporated from the enzootic H6N1 virus lineage by multiple reassortment events. Pathogenicity studies demonstrated heterogeneous results even though all tested viruses had motifs (R-X-K/R-R) supportive of high pathogenicity. Serological surveys for common subtypes of avian viruses confirmed the prevalence of the H5N2 and H6N1 viruses in chickens and revealed an extraordinarily high seroconversion rate to an H9N2 virus, a subtype that is not found in Taiwan but is prevalent in mainland China. These findings suggest that reassortant H5N2 viruses, together with H6N1 viruses, have become established and enzootic in chickens throughout Taiwan and that a large-scale vaccination program might have been conducted locally that likely led to the introduction of the 1994 Mexican-like virus to Taiwan in 2003.