Our systematic influenza surveillance in southern China revealed that two lineages
of H9N2 influenza viruses, represented by Chicken/Beijing/1/94 and Quail/Hong
Kong/G1/97, became endemic in the poultry in southern China since 1990’s. These
established H9N2 lineages continually evolved to generate many different
reassortants (or genotypes) and caused sporadic human infection cases. As
co-circulating with H5N1 influenza viruses, the increasing genetic diversity and the
capability to cause sporadic human infection make the H9N2 viruses become one of
the major candidates with pandemic potential.
Even though highly pathogenic H5N1 influenza viruses were seldom detected at
the live-poultry markets of Hong Kong since 2002, H9N2 viruses were still
commonly isolated in our surveillance program. The accumulated H9N2 isolates
provided an opportunity to get insights into the continual evolution of this subtype
virus in the region. In present study, we have systematically analyzed the H9N2
influenza viruses isolated from 2005 to 2010. Antigenic and phylogenetic analyses of
60 representative H9N2 viruses showed that the Ck/Bei-like H9N2 virus lineage
continued endemic in the terrestrial poultry during the survey period in southern
China. Genotyping analyses revealed four prevalent genotypes or reassortant variants
in the field. Fifty-three of the viruses analyzed belonged to genotype B14 and B15,
which were also the major reassortant variants prevailing in southern China from
2000 to 2005. The remaining seven viruses belonged to novel genotypes that have not
been identified before. Our findings suggested that the Ck/Bei-like lineage continually
maintained high genetic diversity in this region.
The epidemiological findings showed that the isolation rate of H9N2 virus at the
marketing poultry in Hong Kong was dramatically dropped down since 2009, which
was different from what have observed in other provinces in southern China, but was
closely correlated with the hygiene measures implemented in live-poultry markets in
Hong Kong, e.g. not keeping live chicken overnight. These findings suggest the
proper market policy would directly impact the prevalence of influenza virus in the
field. / published_or_final_version / Microbiology / Master / Master of Philosophy
| Identifer | oai:union.ndltd.org:HKU/oai:hub.hku.hk:10722/174388 |
| Date | January 2011 |
| Creators | Chu, Ying-cheung., 朱盈彰. |
| Contributors | Guan, Y |
| Publisher | The University of Hong Kong (Pokfulam, Hong Kong) |
| Source Sets | Hong Kong University Theses |
| Language | English |
| Detected Language | English |
| Type | PG_Thesis |
| Source | http://hub.hku.hk/bib/B47326852 |
| Rights | The author retains all proprietary rights, (such as patent rights) and the right to use in future works., Creative Commons: Attribution 3.0 Hong Kong License |
| Relation | HKU Theses Online (HKUTO) |
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