H9N2 is a subtype of the species Influenza A virus ( bird flu virus).
viruses of domestic ducks have become established in the domestic poultry of Asia. Phylogenetic and antigenic analyses of the H9N2 viruses isolated from Hong Kong markets suggest three distinct sublineages. Among the chicken H9N2 viruses, six of the gene segments were apparently derived from an earlier chicken H9N2 virus isolated in China, whereas the PB1 and PB2 genes are closely related to those of the H5N1 viruses and a quail H9N2 virus A/quail/Hong Kong/G1/97 (Qa/HK/G1/97) suggesting that many of the 1997 chicken H9 isolates in the markets were reassortants." [1 ]
National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), has issued a task order under an existing contract to Chiron Corporation of Emeryville, CA, for the production of an investigational vaccine based on an H9N2 strain of avian influenza virus that has infected humans and has the potential to trigger a modern-day pandemic." [2 ]
Over the years the H9N2 influenza strain caused illness in several children aged nine months to 5 years in
Hong Kong with the latest occurring in December 2009. [3 ] [4 ]
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Further reading [ edit ]
Butt AM, Siddique S, Idrees M, Tong Y (November 2010). "Avian influenza A (H9N2): computational molecular analysis and phylogenetic characterization of viral surface proteins isolated between 1997 and 2009 from the human population". BMC Virology 7 (1): 319. doi: 10.1186/1743-422X-7-319. PMC 2994543. PMID 21078137. "Our findings support the continuous evolution of avian H9N2 viruses towards human as host and are in favor of effective surveillance and better characterization studies to address the issue."
Li C, Yu K, Tian G, et al. (September 2005). "Evolution of H9N2 influenza viruses from domestic poultry in Mainland China". Virology 340 (1): 70–83. doi: 10.1016/j.virol.2005.06.025. PMID 16026813. "Our findings suggest that urgent attention should be paid to the control of H9N2 influenza viruses in animals and to the human's influenza pandemic preparedness."
Centers for Disease Control and Prevention (CDC) - Influenza A(H9N2) infections in Hong Kong published April 8, 1999.
Uyeki TM, Chong YH, Katz JM, et al. (February 2002). "Lack of evidence for human-to-human transmission of avian influenza A (H9N2) viruses in Hong Kong, China 1999". Emerging Infect. Dis. 8 (2): 154–9. doi: 10.3201/eid0802.010148. PMC 2732440. PMID 11897066.
People's Daily Online - Hong Kong reports human case of H9N2 published March 20, 2007.
Xinhua News Agency - HK girl infected with rare but mild A/H9N2 flu virus published December 23, 2009.
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