Characterization of Avian Influenza Viruses A (H5N1) from Wild Birds, Hong Kong, 2004–2008

Smith, Gavin J. D.; Vijaykrishna, Dhanasekaran; Ellis, T.M.; Dyrting, K. C.; Leung, Connie Y. H.; Bahl, Justin; Wong, Chun Wai; Huang, Kai; Chow, Mary K.W.; Duan, Lian; Chan, Allen S. L.; Zhang, Li Juan; Chen, Honglin; Luk, Geraldine; Peiris, Malik; Guan, Yi

doi:10.3201/eid1503.081190

Cited by 97 publications

(69 citation statements)

References 33 publications

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“…It is less likely that they were introduced through intercontinental transmission of subtype H5N5 strains from North America. Considering the endemicity that clade 2.3.4 subtype H5N1 viruses have gained in China since 2005 (7)(8)(9), it is plausible that subtype H5N1 viruses have provided the backbone for generating the novel subtype H5N5 viruses instead of the opposite gene fl ow.…”

Section: Discussionmentioning

confidence: 99%

“…As outlined by the World Health Organization/World Organisation for Animal Health/Food and Agriculture Organization unifi ed nomenclature system for subtype H5N1 highly pathogenic avian infl uenza (HPAI) viruses (6), the HA genes of the 2 subtype H5N5 viruses were classifi ed into clade 2.3.4 ( Figure 1, panel A), which has been the prevalent lineage in southern China since 2005 (7)(8)(9). In addition to the typical residues Q226 and G228 in HA, which confer receptor preference for SAα2,3Gal, infl uenza viruses 008 (H5N5) and 031 (H5N5) simultaneously carried an S227R mutation in the receptor-binding pocket.…”

Section: The Studymentioning

confidence: 99%

See 1 more Smart Citation

Novel Reassortant Highly Pathogenic Avian Influenza (H5N5) Viruses in Domestic Ducks, China

Gu¹,

Liu²,

Cao³

et al. 2011

Emerg. Infect. Dis.

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Section: Discussionmentioning

confidence: 99%

Section: The Studymentioning

confidence: 99%

Novel Reassortant Highly Pathogenic Avian Influenza (H5N5) Viruses in Domestic Ducks, China

Gu¹,

Liu²,

Cao³

et al. 2011

Emerg. Infect. Dis.

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“…It is notable that species not normally associated with avian influenza virus infection have been found to be infected, and examples include sparrows, crows, magpies and storks, and birds of prey that may have fed on infected poultry, e.g. falcons (Monne et al 2008), kestrels (Smith et al 2009), vultures (Ducatez et al 2007a,b) and buzzards (Hars et al 2008). The presence of H5N1 viruses in the bar-headed goose population around Qinghai Lake in late 2005 (Chen et al 2005) provides a striking example of wild-bird infection, and it is postulated that virus was carried from Qinghai Lake westwards through bird migration.…”

Section: Introductionmentioning

confidence: 99%

Within-host variation of avian influenza viruses

Iqbal

Xiao²,

Baillie

et al. 2009

Phil. Trans. R. Soc. B

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The emergence and spread of H5N1 avian influenza viruses from Asia through to Europe and Africa pose a significant animal disease problem and have raised concerns that the virus may pose a pandemic threat to humans. The epizootological factors that have influenced the wide distribution of the virus are complex, and the variety of viruses currently circulating reflects these factors. Sequence analysis of the virus genes sheds light on the H5N1 virus evolution during its emergence and spread, but the degree of virus variation at the level of an individual infected bird has been described in only a few studies. Here, we describe some results of a study in which turkeys, ducks and chickens were infected with either one of two H5N1 or one of three H7N1 viruses, and the degree of sequence variation within an individual infected avian host was examined. We developed 'deep amplicon' sequence analysis for this work, and the methods and results provide a background framework for application to disease outbreaks in the field.

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“…In many cases the risk factors include contact with sick and dying domestic poultry. Many countries that previously declared themselves H5N1 virus-free have now decreed regions a crisis zone following identification of variant H5N1 viruses, which adversely impact global trade in live poultry and poultry products and render current poultry vaccines ineffective [2]. Moreover, virus outbreaks in poultry may be hidden as low pathogenicity avian influenza (LPAI) virus infections and vaccinated birds can be sub clinically infected upon exposure to field virus.…”

Section: Surveillance; H5n1; Virus Outbreak; Pandemic Influenzamentioning

confidence: 99%

Vaccine Control of Avian Influenza H5N1 in Poultry: Need for a Positive Marker

Berry¹

2012

J Vaccines Vaccin

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Highly pathogenic avian influenza (HPAI) H5N1 virus strains have emerged as zoonotic viral pathogens over the last decade and have eluded our serious attempts of control in domestic poultry by vaccination, with numerous countries continuing to have epidemic waves. Although the biology and genomics of H5N1 influenza viruses are well characterized so far, viral outbreaks still occur in domestic poultry, posing a dangerous threat of human transmission. There are two main types of contemporary inactivated vaccines, namely whole virus vaccines and virus vaccines engineered by reverse genetics, both of which are administered with adjuvant to hatchlings and optimally require a booster. However, determinants of vaccine efficacy need to be considered distinctly in chickens versus ducks on a country basis. There is a critical need for detection of infection and vaccination of domestic poultry to control potentially deadly but silent infection in vaccinated flocks. A positive vaccine marker strategy using tetanus toxoid offers advantages for more effective control programs of HPAI including improved capacity for early detection of virus outbreaks and indisputable data for surveillance of vaccinated flocks in vaccination control programs for backyard and village poultry, highly desirable in endemic regions. A DIVA strategy that has been developed for use in Europe exploits a H5N2 vaccine containing a heterologous NA antigen to the circulating H5N1 avian influenza virus [11]. The heterologous NA DIVA approach is based on detection of animals with positive anti-N1 antibody responses before a detectable rise in the flock H5 antibody levels but the anamnestic response in vaccinated poultry to H5 will develop more rapidly than the primary antibody response to N1. Thus, a primary antibody response to the different N subtype to that given in the vaccine takes a longer time to develop than a recall memory antibody response to the H5 antigen, allowing unmonitored virus spread throughout the flock. Current guidelines for serological DIVA testing in Europe, requiring only small sample sizes of 5-10 birds tested for NA antibody, would only provide assurance of detecting infection at the 95% confidence level if over 30% of poultry in the flock have been exposed to field virus [12]. This would likely take at least 3 weeks from introduction of infection to allow detection (one week for the virus to infect sufficient numbers of birds in the flock and a further 2 weeks for development of primary antibody responses in infected birds), a time when infection may no longer be active in the flock [13]. Not all exposed vaccinated poultry will develop antibodies to N1 in the virulent field strain due to limited replication in vaccinated animals [14]. Use of homologous NA antigens in vaccines, particularly for ducks, precludes use of the anti-N1 DIVA strategy. Other DIVA approaches for poultry based on negative markers include anti-NS1 and anti-NP antibody testing for recombinant live virus vector vaccines [15], including rHVT-H5, rNDV-H5 a...

show abstract

Characterization of Avian Influenza Viruses A (H5N1) from Wild Birds, Hong Kong, 2004–2008

Abstract: Repeated detection of subclade 2.3.2 viruses in nonpasserine birds from different regions suggests possible establishment of this lineage in wild bird species.

Cited by 97 publications

References 33 publications

Novel Reassortant Highly Pathogenic Avian Influenza (H5N5) Viruses in Domestic Ducks, China

Novel Reassortant Highly Pathogenic Avian Influenza (H5N5) Viruses in Domestic Ducks, China

Within-host variation of avian influenza viruses

Vaccine Control of Avian Influenza H5N1 in Poultry: Need for a Positive Marker

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