Pathogenicity and Vaccine Efficacy of Different Clades of Asian H5N1 Avian Influenza A Viruses in Domestic Ducks

Kim, Jeong-Ki; Seiler, Patrick; Forrest, H. S.; Khalenkov, Alexey M.; Franks, John; Kumar, Mahesh; Karesh, William B.; Gilbert, Martin; Sodnomdarjaa, Ruuragchaa; Douangngeun, Bounlom; Govorkova, Elena A.; Webster, Robert G.

doi:10.1128/jvi.01176-08

Cited by 73 publications

(41 citation statements)

References 48 publications

(52 reference statements)

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“…Indeed, clade 1 was found to be a good antigen for detection of HI antibody responses [25] and previous studies at the Agriculture, Fisheries and Conservation Department in Hong Kong confirmed this good cross-reactivity (T. Ellis, personal communication [7] and no information about the cross-reactivity with those strains is available. Nevertheless, this clade was not so well established at the time of the study period as indicated by a very low isolation rate compared to clade 2.3.4 in about 20 000 samples collected from 2007 to 2010 [7].…”

Section: Methodsmentioning

confidence: 97%

Evaluation of the vaccination efficacy against H5N1 in domestic poultry in the Red River Delta in Vietnam

et al. 2012

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SUMMARYThe domestic poultry population in Vietnam has been vaccinated against highly pathogenic avian influenza (HPAI) H5N1 since 2005. Since then, outbreaks have continued to occur without a clear understanding of the mechanisms involved. The general objective of this study was to understand the epidemiology of the disease in the context of vaccination and to draw some conclusions about vaccination efficacy in the domestic poultry population of the Red River Delta area. Five cross-sectional surveys to measure the serological and virological prevalence in vaccinated and unvaccinated poultry were performed from the end of 2008 to June 2010. The global seroprevalence was 24 % (95 % confidence interval 19 . 9-28 . 2). Determinants of vaccine immunogenicity were identified separately in chickens and ducks as well as determinants of the seroconversion in unvaccinated birds. The results highlight the difficulties in maintaining good flock immunity in poultry populations using inactivated vaccine in the field with two vaccination rounds per year, and in preventing circulation of virus in co-existing unvaccinated poultry.

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Section: Methodsmentioning

confidence: 97%

Evaluation of the vaccination efficacy against H5N1 in domestic poultry in the Red River Delta in Vietnam

et al. 2012

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“…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. The observations that, following experimental infection, a small number of ducks of several species showed severe disease signs lend support to the notion that spread through wild birds is feasible (Hulse-Post et al 2005;Sturm-Ramirez et al 2005;Keawcharoen et al 2008;Kim et al 2008;Londt et al 2008), yet the relative importance of wild birds in transmission of the H5N1 virus remains an open question.…”

Section: Introductionmentioning

confidence: 90%

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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“…Natural H5N1 virus isolates are highly pathogenic in many, but not all, duck species (21,47,48), and their transmission among wild ducks and from wild ducks to domestic poultry and mammals, including humans, has been a key element in their natural ecology (10,33,54). Moreover, wild ducks are thought to be a main reservoir of low-pathogenicity avian influenza viruses (33).…”

Section: Discussionmentioning

confidence: 99%

“…Groups of three 4-week-old mallards (Anas platyrhynchos) were inoculated via intranasal, intraocular, and intratracheal instillation of ϳ10 6 50% egg infective doses (EID 50 ) of virus in a 1-ml volume, as described previously (21). Two uninoculated contact ducks were placed in the cage with the inoculated ducks 24 h postinoculation (p.i.…”

Section: Methodsmentioning

confidence: 99%

The pH of Activation of the Hemagglutinin Protein Regulates H5N1 Influenza Virus Pathogenicity and Transmissibility in Ducks

Reed

Bridges

Seiler

et al. 2010

J Virol

Self Cite

133

187

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While the molecular mechanism of membrane fusion by the influenza virus hemagglutinin (HA) protein has been studied extensively in vitro, the role of acid-dependent HA protein activation in virus replication, pathogenesis, and transmission in vivo has not been characterized. To investigate the biological significance of the pH of activation of the HA protein, we compared the properties of four recombinant viruses with altered HA protein acid stability to those of wild-type influenza virus A/chicken/Vietnam/C58/04 (H5N1) in vitro and in mallards. Membrane fusion by wild-type virus was activated at pH 5.9. Wild-type virus had a calculated environmental persistence of 62 days and caused extensive morbidity, mortality, shedding, and transmission in mallards. An N114K mutation that increased the pH of HA activation by 0.5 unit resulted in decreased replication, genetic stability, and environmental stability. Changes of ؉0.4 and ؊0.5 unit in the pH of activation by Y23H and K58I mutations, respectively, reduced weight loss, mortality, shedding, and transmission in mallards. An H24Q mutation that decreased the pH of activation by 0.3 unit resulted in weight loss, mortality, clinical symptoms, and shedding similar to those of the wild type. However, the HA-H24 1 Q virus was shed more extensively into drinking water and persisted longer in the environment. The pH of activation of the H5 HA protein plays a key role in the propagation of H5N1 influenza viruses in ducks and may be a novel molecular factor in the ecology of influenza viruses. The data also demonstrate that H5N1 neuraminidase activity increases the pH of activation of the HA protein in vitro.

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Pathogenicity and Vaccine Efficacy of Different Clades of Asian H5N1 Avian Influenza A Viruses in Domestic Ducks

Cited by 73 publications

References 48 publications

Evaluation of the vaccination efficacy against H5N1 in domestic poultry in the Red River Delta in Vietnam

Evaluation of the vaccination efficacy against H5N1 in domestic poultry in the Red River Delta in Vietnam

Within-host variation of avian influenza viruses

The pH of Activation of the Hemagglutinin Protein Regulates H5N1 Influenza Virus Pathogenicity and Transmissibility in Ducks

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