Clade 2.3.2 Avian Influenza Virus (H5N1), Qinghai Lake Region, China, 2009–2010 | CDC EID

EID Journal Home > Volume 17, Number 3–March 2011

Volume 17, Number 3–March 2011
Letter
Clade 2.3.2 Avian Influenza Virus (H5N1), Qinghai Lake Region, China, 2009–2010
Xudong Hu,1 Di Liu,1 Mingyang Wang, Le Yang, Ming Wang, Qingyu Zhu, Laixing Li, and George F. Gao

Author affiliations: China Agricultural University College of Veterinary Medicine, Beijing, People's Republic of China (X. Hu, Ming Wang, G.F. Gao); Chinese Academy of Sciences (CAS) Key Laboratory of Pathogenic Microbiology and Immunology Institute of Microbiology, Beijing (X. Hu, D. Liu, Mingyang Wang, G.F. Gao); Graduate University CAS, Beijing (Mingyang Wang, G.F. Gao); Northwestern Institute of Plateau Biology CAS, Xining, China (L. Yang, L. Li); Tibet Plateau Institute of Biology, Lhasa, Tibet Autonomous Region, China (L. Yang); State Key Laboratory of Pathogens and Biosecurity Academy of Military Medical Sciences, Beijing (Q. Zhu); and Beijing Institutes of Life Sciences CAS, Beijing (G.F. Gao)

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To the Editor: In 2005, a large population of wild migratory birds was infected with highly pathogenic avian influenza (HPAI) virus (H5N1) in the Qinghai Lake region of western People's Republic of China, resulting in the death of ≈10,000 birds (1,2). On the basis of phylogenetic analysis of the hemagglutinin (HA) gene, the virus was classified as clade 2.2 according to the World Health Organization guidelines. Subsequently, viruses from this clade were found in Mongolia, Russia, Europe, and Africa along the migratory flyways of birds (3,4). This unique distribution of the same clade of HPAI virus (H5N1) through different migratory routes indicates that migratory birds might play a global role in virus dissemination (3,4).

In 2006, viruses from the same clade were isolated in the Qinghai Lake region (3). Analysis of viral outbreaks along migratory flyways demonstrated a similar outbreak pattern for the past 4 years (2006–2009) (5). During that period, clade 2.2 avian influenza virus (H5N1) was isolated in China, Mongolia, Russia, Germany, Egypt, and Nigeria; all viruses were closely related to the Qinghai Lake virus. Despite the broad distribution of clade 2.2 viruses in migratory flyways, few isolates of clade 2.2 viruses in local domestic poultry were reported, especially in China (6). Outbreaks of these viruses were reported in poultry in Africa (7). The reason these viruses rarely cause outbreaks in poultry is unknown.

During May–June 2009 and 2010, several dead migratory birds were found in the Qinghai Lake region. Nine HPAI viruses (H5N1) were isolated in 2009 and 2 were isolated in 2010 from great cormorants (Phalacrocorax carbo), brown-headed gulls (Chroicocephalus brunnicephalus), great black-headed gulls (Ichthyaetus ichthyaetus), great-crested grebes (Podiceps cristatus), and bar-headed geese (Anser indicus) and serotyped as described (3). HA genes from all 11 isolates were subsequently amplified by using reverse transcription–PCR and sequenced.

full-text:
Clade 2.3.2 Avian Influenza Virus (H5N1), Qinghai Lake Region, China, 2009–2010 | CDC EID


Suggested Citation for this Article
Hu X, Liu D, Wang M, Yang L, Wang M, Zhu Q, et al. Clade 2.3.2 avian influenza virus (H5N1), Qinghai Lake region, China, 2009–2010 [letter]. Emerg Infect Dis [serial on the Internet]. 2011 Mar [date cited].
http://www.cdc.gov/EID/content/17/3/560.htm


DOI: 10.3201/eid1703.100948



1These authors contributed equally to this article.


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George F. Gao, CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China; email: gaof@im.ac.cn