Human Infection with Influenza Virus A(H10N8) from Live Poultry Markets, China, 2014

Tao Zhang, Yuhai Bi, Huaiyu Tian, Xiaowen Li, Di Liu, Ying Wu, Tao Jin, Yong Wang, Quanjiao Chen, Ze Chen, Jianyu Chang, George F. Gao, and Bing Xu

Author affiliations: Ministry of Education Key Laboratory for Earth System Modelling, Center for Earth System Science and School of Environment, Tsinghua University, Beijing, China (T. Zhang, Y. Wang, B. Xu); Chinese Academy of Sciences Institute of Microbiology, Beijing (Y. Bi, D. Liu, Y. Wu, G.F. Gao); Beijing Normal University, Beijing (H. Tian, X. Li, B. Xu); BGI-Shenzhen, Shenzhen, China (T. Jin); Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China (Q. Chen, Z. Chen); China Agricultural University, Beijing (J. Chang); Chinese Center for Disease Control and Prevention, Beijing (G.F. Gao)

Abstract

Human infection with avian influenza virus A(H10N8) was initially reported in China in December 2013. We characterized H10N8 strains from a human patient and from poultry in live markets that infected persons had visited. Results of genome sequencing and virus characterization suggest that the virus strains that infected humans originated from these markets.

Avian influenza virus (AIV) is classified into 16 subtypes on the basis of hemagglutinin (HA) and 9 subtypes on the basis of neuraminidase (NA); additional bat-derived influenza-like genomes, H17N10 and H18N11, have recently been reported (1). Birds can be infected with AIV through direct contact with infected hosts or through contact with contaminated surfaces or materials, including water and food. In China, H10N8 virus was isolated from the environment of Dongting Lake in Hunan Province in 2007 (2) and from a duck in a live poultry market (LPM) in Guangdong Province in 2012 (3). This AIV was not then known to directly infect humans or other mammals.

In December 2013, H10N8 virus infection in a person was reported in Nanchang, Jiangxi Province, China (4); 2 more human cases followed. The initial reported case was in a 73-year-old woman who visited a local LPM 4 days before the onset of her illness (4). Because genetic information on AIV is essential for understanding of the biology of these viruses, their spread among avian species, and their potential transmission to humans, in January 2014, we conducted surveillance of several LPMs in Nanchang, including those visited by the 3 reported case-patients, to determine the source of these infections.

The Study

During January 2014, we collected 226 pairs of cloacal and oropharyngeal swab specimens from apparently healthy poultry in several LPMs in Nanchang, China. The samples were stored in viral medium at 4°C until they were transported to the laboratory and then stored at −80°C until analysis. Virus material was injected into 10-day-old specific pathogen free embryonated chicken eggs; we then genetically analyzed all HA-positive samples. Viral RNA from allantoic fluid was extracted with the RNeasy Mini Kit (QIAGEN, Hilden, Germany), and cDNAs were synthesized from the viral RNA by reverse transcription PCR by using a SuperScript First-Strand Synthesis System for RT-PCR Kit (Invitrogen, Carlsbad, CA, USA). All gene segments were amplified by using a Phusion High-Fidelity PCR Kit (New England Biolabs, Ipswich, MA, USA). The PCR products were sequenced and the sequences were edited and aligned by using BioEdit software (http://www.mbio.ncsu.edu/bioedit/bioedit.html ).