Continued Evolution of H5N1 Influenza Viruses in Wild Birds, Domestic Poultry, and Humans in China from 2004 to 2009

Animal Influenza Laboratory of the Ministry of Agriculture and National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, CAAS, 427 Maduan Street, Harbin 150001, People's Republic of China.
Journal of Virology (Impact Factor: 4.44). 09/2010; 84(17):8389-97. DOI: 10.1128/JVI.00413-10
Source: PubMed


Despite substantial efforts to control H5N1 avian influenza viruses (AIVs), the viruses have continued to evolve and cause disease outbreaks in poultry and infections in humans. In this report, we analyzed 51 representative H5N1 AIVs isolated from domestic poultry, wild birds, and humans in China during 2004 to 2009, and 21 genotypes were detected based on whole-genome sequences. Twelve genotypes of AIVs in southern China bear similar H5 hemagglutinin (HA) genes (clade 2.3). These AIVs did not display antigenic drift and could be completely protected against by the A/goose/Guangdong/1/96 (GS/GD/1/96)-based oil-adjuvanted killed vaccine and recombinant Newcastle disease virus vaccine, which have been used in China. In addition, antigenically drifted H5N1 viruses, represented by A/chicken/Shanxi/2/06 (CK/SX/2/06), were detected in chickens from several provinces in northern China. The CK/SX/2/06-like viruses are reassortants with newly emerged HA, NA, and PB1 genes that could not be protected against by the GS/GD/1/96-based vaccines. These viruses also reacted poorly with antisera generated from clade 2.2 and 2.3 viruses. The majority of the viruses isolated from southern China were lethal in mice and ducks, while the CK/SX/2/06-like viruses caused mild disease in mice and could not replicate in ducks. Our results demonstrate that the H5N1 AIVs circulating in nature have complex biological characteristics and pose a continued challenge for disease control and pandemic preparedness.

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Available from: Jinying ge, Dec 31, 2013
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    • "To date, the literature reports that only viruses of the H5 and H7 subtypes are highly pathogenic (HP) in susceptible species (Hampson and Mackenzie, 2006; Alexander, 2007). H5N1 highly pathogenic avian influenza virus (HPAIV) isolates derived from the goose/Guangdong/1/96 (Gs/GD) lineage have been found in over sixty countries in Europe, Asia, and Africa (Li et al., 2004). They not only cause high mortality in birds and thus serious damage to the poultry industry; they also occasionally infect humans and are feared to have be the potential source of a new pandemic flu (Chen et al., 2004; Guan et al., 2004; Li et al., 2004; Peiris et al., 2007; Wang et al., 2008). "
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    • "Conventional inactivated vaccines have proven to be effective for the control and prevention of avian influenza outbreaks. However, outbreaks of H5 AIV still continue to occur in poultry [3]. To develop an improved vaccine against AI, recombinant DNA technology has been used to generate live virus vaccines. "
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    • "Moreover, the impact of OAS to protection against subsequent heterologous H5N1 HPAIV infection in humans and other animals may also exhibit individual differences. As reported in our recent studies, evolution of H5N1 HPAIV has resulted in continuing antigenic drift of these viruses [19]. The genetic and biological complexity of the H5N1 HPAIV detected in recent years in China alone indicates that reassortant viruses are constantly generated during natural infection of avian species, which may enable these lethal viruses to gain transmissibility in humans. "
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