151
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Yang J, Xia H, Zhao J, He X, Pan L, Tang S, Zhang Z, Kou Z, Li T. Molecular characterization of avian influenza virus (H7N8) isolated from poultry in Central China in the mid-1980s. CHINESE SCIENCE BULLETIN-CHINESE 2010. [DOI: 10.1007/s11434-010-3148-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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152
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Horimoto T, Yamada S, Kawaoka Y. [Virological characteristics of pandemic (H1N1) 2009 influenza virus]. Uirusu 2010; 60:3-8. [PMID: 20848859 DOI: 10.2222/jsv.60.3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
In the spring of 2009, a novel swine-origin H1N1 virus, whose antigenicity is quite different from those of seasonal human H1N1 strains, emerged in Mexico and readily transmitted and spread among humans, resulting in the first influenza pandemic in the 21st century. This novel H1N1 virus was shown to be a triple reassortant comprising genes derived from avian, human, and swine viruses. Here, we review our current knowledge of this pandemic influenza virus and discuss future aspects of the pandemic.
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Affiliation(s)
- Taisuke Horimoto
- Division of Virology, Institute of Medical Science, University of Tokyo.
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153
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Nunthaboot N, Rungrotmongkol T, Malaisree M, Decha P, Kaiyawet N, Intharathep P, Sompornpisut P, Poovorawan Y, Hannongbua S. Molecular insights into human receptor binding to 2009 H1N1 influenza A hemagglutinin. MONATSHEFTE FUR CHEMIE 2010. [DOI: 10.1007/s00706-010-0319-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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154
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Species-specific contribution of the four C-terminal amino acids of influenza A virus NS1 protein to virulence. J Virol 2010; 84:6733-47. [PMID: 20410267 DOI: 10.1128/jvi.02427-09] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Large-scale sequence analyses of influenza viruses revealed that nonstructural 1 (NS1) proteins from avian influenza viruses have a conserved C-terminal ESEV amino acid motif, while NS1 proteins from typical human influenza viruses have a C-terminal RSKV motif. To test the influence of the C-terminal domains of NS1 on the virulence of an avian influenza virus, we generated a wild-type H7N1 virus with an ESEV motif and a mutant virus with an NS1 protein containing a C-terminal RSKV motif by reverse genetics. We compared the phenotypes of these viruses in vitro in human, mouse, and duck cells as well as in vivo in mice and ducks. In human cells, the human C-terminal RSKV domain increased virus replication. In contrast, the avian C-terminal ESEV motif of NS1 increased virulence in mice. We linked this increase in pathogenicity in mice to an increase in virus replication and to a more severe lung inflammation associated with a higher level of production of type I interferons. Interestingly, the human C-terminal RSKV motif of NS1 increased viral replication in ducks. H7N1 virus with a C-terminal RSKV motif replicated to higher levels in ducks and induced higher levels of Mx, a type I interferon-stimulated gene. Thus, we identify the C-terminal domain of NS1 as a species-specific virulence domain.
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155
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Tatebe K, Zeytun A, Ribeiro RM, Hoffmann R, Harrod KS, Forst CV. Response network analysis of differential gene expression in human epithelial lung cells during avian influenza infections. BMC Bioinformatics 2010; 11:170. [PMID: 20370926 PMCID: PMC2868837 DOI: 10.1186/1471-2105-11-170] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Accepted: 04/06/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The recent emergence of the H5N1 influenza virus from avian reservoirs has raised concern about future influenza strains of high virulence emerging that could easily infect humans. We analyzed differential gene expression of lung epithelial cells to compare the response to H5N1 infection with a more benign infection with Respiratory Syncytial Virus (RSV). These gene expression data are then used as seeds to find important nodes by using a novel combination of the Gene Ontology database and the Human Network of gene interactions. Additional analysis of the data is conducted by training support vector machines (SVM) with the data and examining the orientations of the optimal hyperplanes generated. RESULTS Analysis of gene clustering in the Gene Ontology shows no significant clustering of genes unique to H5N1 response at 8 hours post infection. At 24 hours post infection, however, a number of significant gene clusters are found for nodes representing "immune response" and "response to virus" terms. There were no significant clusters of genes in the Gene Ontology for the control (Mock) or RSV experiments that were unique relative to the H5N1 response. The genes found to be most important in distinguishing H5N1 infected cells from the controls using SVM showed a large degree of overlap with the list of significantly regulated genes. However, though none of these genes were members of the GO clusters found to be significant. CONCLUSIONS Characteristics of H5N1 infection compared to RSV infection show several immune response factors that are specific for each of these infections. These include faster timescales within the cell as well as a more focused activation of immunity factors. Many of the genes that are found to be significantly expressed in H5N1 response relative to the control experiments are not found to cluster significantly in the Gene Ontology. These genes are, however, often closely linked to the clustered genes through the Human Network. This may suggest the need for more diverse annotations of these genes and verification of their action in immune response.
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Affiliation(s)
- Ken Tatebe
- Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ahmet Zeytun
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Ruy M Ribeiro
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Robert Hoffmann
- Computational Biology Center, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Kevin S Harrod
- Lovelace Respiratory Research Institute, Albuquerque, NM, USA
| | - Christian V Forst
- Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
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156
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Khatri M, O'Brien TD, Goyal SM, Sharma JM. Isolation and characterization of chicken lung mesenchymal stromal cells and their susceptibility to avian influenza virus. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2010; 34:474-479. [PMID: 20026347 PMCID: PMC7124449 DOI: 10.1016/j.dci.2009.12.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Revised: 12/14/2009] [Accepted: 12/14/2009] [Indexed: 05/28/2023]
Abstract
In this study, we isolated and characterized mesenchymal stromal cells (MSCs) from the lungs of 1- to 2-week-old chickens. Microscopically, the cultured cells showed fibroblast-like morphology. Phenotypically these cells expressed CD44, CD90, CD105 and the transcription factor PouV, which has been shown to be critical for stem cell self-renewal and pluripotency. The multipotency of chicken MSCs was demonstrated by their ability to undergo adipogenic and osteogenic differentiation. Like chicken bone marrow MSCs and mammalian MSCs, chicken lung MSCs had immunoregulatory activity and profoundly suppressed the proliferative capacity of T cells in response to a mitogenic stimulus. Next, we examined the susceptibility of these cells to H1N1 and H9N5 avian influenza (AI) viruses. The lung MSCs were shown to express known influenza virus alpha-2,3 and alpha-2,6 sialic acid receptors and to support replication of both the avian H1N1 and avian H9N5 influenza strains. Viral infection of MSCs resulted in cell lysis and cytokine and chemokine production. Further characterization of lung MSCs in chicken and other mammalian species may help in understanding the pathogenesis of infectious and non-infectious lung diseases and the mechanisms of lung injury repair.
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Affiliation(s)
- Mahesh Khatri
- Department of Veterinary Biomedical Sciences, University of Minnesota, 1971 Commonwealth Avenue, St. Paul, MN 55108, USA.
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157
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Baek YH, Pascua PNQ, Song MS, Park KJ, Kwon HI, Lee JH, Kim SY, Moon HJ, Kim CJ, Choi YK. Surveillance and characterization of low pathogenic H5 avian influenza viruses isolated from wild migratory birds in Korea. Virus Res 2010; 150:119-28. [PMID: 20227447 DOI: 10.1016/j.virusres.2010.03.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Revised: 03/03/2010] [Accepted: 03/04/2010] [Indexed: 11/30/2022]
Abstract
Migratory waterfowls are the natural reservoir of influenza A viruses. However, interspecies transmission had occasionally caused outbreaks in various hosts including humans. To characterize the genetic origins of H5 avian influenza viruses isolated from migratory birds in South Korea, phylogenetic analysis were conducted. A total of 53 H5 viruses were isolated between October 2005 and November 2008. Full genetic characterization indicated that most of these viruses belong to the Eurasian-like avian lineage. However, some segments of the AB/Korea/W235/07 and the AB/Korea/W236/07 isolates were clustered with North American lineage viruses rather than those of the Eurasian lineage, suggesting the occurrence of reassortment between these two avian virus lineages. Phylogenetic analysis further demonstrated that the H5N2 and H5N3 virus isolates were of the low pathogenicity H5 phenotype. The H5 viruses appear to be antigenically similar to each other, but could be distinguished from a recent HPAI H5N1 (EM/Korea/W149/06) virus by hemagglutinin inhibition (HI) assays. Experimental inoculation of representative viruses indicated that certain isolates, particularly AB/Korea/W163/07 (H5N2), could be detected in trachea and lungs of chickens but none could be transmitted by direct contact. Furthermore, all of the viruses could be detected in mice lung without prior adaptation which is indicative of their pathogenic potential in a mammalian host. Overall, our results emphasize the important role that migratory birds play in the perpetuation, transport, and reassortment of avian influenza viruses stressing the need for continued surveillance of influenza virus activity in these avian populations.
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Affiliation(s)
- Yun Hee Baek
- College of Medicine and Medical Research Institute, Chungbuk National University, 12 Gaeshin-Dong, Heungduk-Ku, Cheongju 361-763, Republic of Korea
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158
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Knowledge and anticipated attitudes of the community about bird flu outbreak in Turkey, 2007-2008: a survey-based descriptive study. Int J Public Health 2010; 56:163-8. [PMID: 20217176 DOI: 10.1007/s00038-010-0131-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 11/09/2009] [Accepted: 02/15/2010] [Indexed: 10/19/2022] Open
Abstract
OBJECTIVE To determine factors associated with knowledge and anticipated attitudes to a foreseen avian influenza outbreak in a high-risk population from a Turkish remote region. METHODS A random, cross-sectional face-to-face survey of 1,046 Turkish adults. RESULTS The proportion of participants concerned about contracting the virus was significantly lower amongst the less educated and rural located respondents. Significantly more rural than urban located participants declared not complying with quarantine policies and not handing out their poultry in case of an influenza outbreak. Factors associated with protective behaviours were higher level of education, urban location, not performing backyard farming of poultry, and preferring ready-to-eat products. CONCLUSIONS Preparedness against bird flu endemic in remote regions could be hindered by factors, such as low levels of education and economic dependence on small-scale backyard farming. The baseline data collected in this survey will be useful in monitoring changes over time in the population's perceptions of threat, and its attitude towards compliance with specific public health recommendations.
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159
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Results of the influenza virus surveillance in wild birds in Western part of Mongolia. ASIAN PAC J TROP MED 2010. [DOI: 10.1016/s1995-7645(10)60042-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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160
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Highly pathogenic H5N1 avian influenza virus induces extracellular Ca2+ influx, leading to apoptosis in avian cells. J Virol 2010; 84:3068-78. [PMID: 20053741 DOI: 10.1128/jvi.01923-09] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this study, we show that the highly pathogenic H5N1 avian influenza virus (AIV) (A/crow/Kyoto/53/04 and A/chicken/Egypt/CL6/07) induced apoptosis in duck embryonic fibroblasts (DEF). In contrast, apoptosis was reduced among cells infected with low-pathogenic AIVs (A/duck/HK/342/78 [H5N2], A/duck/HK/820/80 [H5N3], A/wigeon/Osaka/1/01 [H7N7], and A/turkey/Wisconsin/1/66 [H9N2]). Thus, we investigated the molecular mechanisms of apoptosis induced by H5N1-AIV infection. Caspase-dependent and -independent pathways contributed to the cytopathic effects. We further showed that, in the induction of apoptosis, the hemagglutinin of H5N1-AIV played a major role and its cleavage sequence was not critical. We also observed outer membrane permeabilization and loss of the transmembrane potential of the mitochondria of infected DEF, indicating that mitochondrial dysfunction was caused by the H5N1-AIV infection. We then analyzed Ca(2+) dynamics in the infected cells and demonstrated an increase in the concentration of Ca(2+) in the cytosol ([Ca(2+)](i)) and mitochondria ([Ca(2+)](m)) after H5N1-AIV infection. Regardless, gene expression important for regulating Ca(2+) efflux from the endoplasmic reticulum did not significantly change after H5N1-AIV infection. These results suggest that extracellular Ca(2+) may enter H5N1-AIV-infected cells. Indeed, EGTA, which chelates extracellular free Ca(2+), significantly reduced the [Ca(2+)](i), [Ca(2+)](m), and apoptosis induced by H5N1-AIV infection. In conclusion, we identified a novel mechanism for influenza A virus-mediated cell death, which involved the acceleration of extracellular Ca(2+) influx, leading to mitochondrial dysfunction and apoptosis. These findings may be useful for understanding the pathogenesis of H5N1-AIV in avian species as well as the impact of Ca(2+) homeostasis on influenza A virus infection.
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161
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Shapiro DS. Infections acquired from animals other than pets. Infect Dis (Lond) 2010. [DOI: 10.1016/b978-0-323-04579-7.00069-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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162
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The pH of activation of the hemagglutinin protein regulates H5N1 influenza virus pathogenicity and transmissibility in ducks. J Virol 2009; 84:1527-35. [PMID: 19923184 DOI: 10.1128/jvi.02069-09] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
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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163
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Neumann G, Chen H, Gao GF, Shu Y, Kawaoka Y. H5N1 influenza viruses: outbreaks and biological properties. Cell Res 2009; 20:51-61. [PMID: 19884910 DOI: 10.1038/cr.2009.124] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
All known subtypes of influenza A viruses are maintained in wild waterfowl, the natural reservoir of these viruses. Influenza A viruses are isolated from a variety of animal species with varying morbidity and mortality rates. More importantly, influenza A viruses cause respiratory disease in humans with potentially fatal outcome. Local or global outbreaks in humans are typically characterized by excess hospitalizations and deaths. In 1997, highly pathogenic avian influenza viruses of the H5N1 subtype emerged in Hong Kong that transmitted to humans, resulting in the first documented cases of human death by avian influenza virus infection. A new outbreak started in July 2003 in poultry in Vietnam, Indonesia, and Thailand, and highly pathogenic avian H5N1 influenza viruses have since spread throughout Asia and into Europe and Africa. These viruses continue to infect humans with a high mortality rate and cause worldwide concern of a looming pandemic. Moreover, H5N1 virus outbreaks have had devastating effects on the poultry industries throughout Asia. Since H5N1 virus outbreaks appear to originate from Southern China, we here examine H5N1 influenza viruses in China, with an emphasis on their biological properties.
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Affiliation(s)
- Gabriele Neumann
- Department of Pathological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53711, USA
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164
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Tscherne DM, Manicassamy B, García-Sastre A. An enzymatic virus-like particle assay for sensitive detection of virus entry. J Virol Methods 2009; 163:336-43. [PMID: 19879300 DOI: 10.1016/j.jviromet.2009.10.020] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 10/15/2009] [Accepted: 10/20/2009] [Indexed: 10/20/2022]
Abstract
A viral entry assay where a beta-lactamase reporter protein fused to the influenza matrix protein-1 (BlaM1) is packaged as a structural component into influenza virus-like particles (VLPs) is described. The Bla reporter is released upon fusion with target cells and can be detected in live cells by flow cytometry, microscopy, or fluorometric plate reader for utility in high-throughput screening approaches. The production of BlaM1 VLPs and subsequent transfer of Bla activity to target cells requires the presence of influenza hemagglutinin (HA) and neuraminidase (NA). In addition, transfer of Bla by the VLPs can be blocked by an influenza neutralizing antibody, is impeded by a chemical inhibitor of influenza virus entry, and requires HA that is cleaved by a protease specific for its cleavage site. An analogous VLP system also was developed for Ebola (EBOV) and Marburg (MARV) viruses, demonstrating that this straightforward assay has broad application for studying the entry steps of enveloped viruses, especially those that require high levels of biosafety containment.
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Affiliation(s)
- Donna M Tscherne
- Department of Microbiology, Mount Sinai School of Medicine, 1 Gustave L. Levy Place, New York, NY 10029, USA
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165
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Tao P, Luo M, Zhu D, Qu S, Yang Z, Gao M, Guo D, Pan Z. Virus-like particle vaccine comprised of the HA, NA, and M1 proteins of an avian isolated H5N1 influenza virus induces protective immunity against homologous and heterologous strains in mice. Viral Immunol 2009; 22:273-81. [PMID: 19594398 DOI: 10.1089/vim.2009.0017] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Highly pathogenic avian influenza H5N1 virus represents a growing threat for an influenza pandemic. Development of effective vaccines for H5N1 is a priority for pandemic preparedness. Focusing on influenza virus-like particles (VLPs) has been suggested as a promising vaccine approach. Recent VLP vaccination efforts have been concentrated on the H5N1 strains isolated from humans. Because all confirmed cases of human H5N1 infection were directly transmitted from infected poultry, it is of interest to develop VLP vaccines comprised of antigenic proteins of avian H5N1 strains in order to compare their efficacy in fighting diverse H5N1 strains with vaccines developed using human isolates. In this study, we generated a VLP vaccine composed of the HA, NA, and M1 proteins of the avian H5N1 influenza virus isolate A/chicken/Hubei/489/2004, which seems to occupy a unique phylogenetic position; it belongs to neither clade 1 nor clade 2. Upon infection of Sf9 insect cells using recombinant baculoviruses, the co-expressed HA, NA, and M1 proteins self-assembled and released into the culture medium as VLPs. In a mouse model, purified VLPs elicited an effective antibody response and conferred complete protection against heterologous human H5N1 influenza virus, as well as a homologous avian H5N1 influenza virus isolate. Our work provides further evidence that vaccination with influenza VLPs may be a productive approach to achieve protection against diverse H5N1 strains.
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Affiliation(s)
- Pan Tao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, HuBei, China
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166
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King MD, Guentzel MN, Arulanandam BP, Lupiani B, Chambers JP. Proteolytic bacteria in the lower digestive tract of poultry may affect avian influenza virus pathogenicity. Poult Sci 2009; 88:1388-93. [PMID: 19531708 DOI: 10.3382/ps.2008-00549] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Proteolytic cleavage of hemagglutinin is required for cell entry by receptor-mediated endocytosis and plays a key role in pathogenicity of the influenza virus. Despite several studies describing relationships between bacterial proteases and influenza A viral activation in mammals, very little is known about the role of the normal bacterial flora of birds on hemagglutinin activation. We examined the indigenous intestinal microflora of 100 mixed-sex, 27-d-old Ross chickens from a commercial poultry facility for protease-secreting bacteria. Protease-secreting bacteria were isolated from 82 of 100 chickens with 50 birds exhibiting 2 or more protease-secreting bacterial species. A total of 20 protease-secreting bacterial species were identified: 17 gram-positive cocci, 2 gram-positive rods, and 1 gram-negative rod. Enterococcus faecalis, Enterococcus gallinarum, and Proteus mirabilis were the most frequently observed protease-secreting bacterial species. The presence of proteolytic bacteria in the intestinal tract of poultry in this study suggests the possibility of yet-to-be-described role(s) in cleavage of hemagglutinin that may alter the pathogenicity of avian influenza viruses.
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Affiliation(s)
- M D King
- Department of Civil and Environmental Engineering, College of Engineering, The University of Texas at San Antonio 78249, USA
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167
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Characterization of H3N6 avian influenza virus isolated from a wild white pelican in Zambia. Arch Virol 2009; 154:1517-22. [PMID: 19655084 DOI: 10.1007/s00705-009-0467-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 07/08/2009] [Indexed: 10/20/2022]
Abstract
We characterized an influenza virus isolated from a great white pelican in Zambia. Phylogenetic analysis showed that all of its gene segments belonged to the Eurasian lineage and that they appear to have evolved in distinct geographical regions in Europe, Asia, and Africa, suggesting reassortment of virus genes maintained in wild aquatic birds whose flyways overlap across these continents. It is notable that this virus might possess some genes of the same origin as those of highly pathogenic H7 and H5 viruses isolated in Eurasia. The present study underscores the need for continued monitoring of avian influenza viruses in Eurasia and Africa.
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168
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Characterization of an avian influenza virus H5N1 Egyptian isolate. J Virol Methods 2009; 159:244-50. [DOI: 10.1016/j.jviromet.2009.04.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2008] [Revised: 04/10/2009] [Accepted: 04/20/2009] [Indexed: 11/18/2022]
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169
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McGill J, Heusel JW, Legge KL. Innate immune control and regulation of influenza virus infections. J Leukoc Biol 2009; 86:803-12. [PMID: 19643736 DOI: 10.1189/jlb.0509368] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Adaptive immune responses are critical for the control and clearance of influenza A virus (IAV) infection. However, in recent years, it has become increasingly apparent that innate immune cells, including natural killer cells, alveolar macrophages (aMphi), and dendritic cells (DC) are essential following IAV infection in the direct control of viral replication or in the induction and regulation of virus-specific adaptive immune responses. This review will discuss the role of these innate immune cells following IAV infection, with a particular focus on DC and their ability to induce and regulate the adaptive IAV-specific immune response.
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Affiliation(s)
- Jodi McGill
- Department of Pathology and Interdisciplinary Graduate Program in Immunology, University of Iowa, Iowa City, Iowa 52242, USA
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170
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Hammerling U, Tallsjö A, Grafström R, Ilbäck NG. Comparative Hazard Characterization in Food Toxicology. Crit Rev Food Sci Nutr 2009; 49:626-69. [DOI: 10.1080/10408390802145617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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171
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Rungrotmongkol T, Decha P, Sompornpisut P, Malaisree M, Intharathep P, Nunthaboot N, Udommaneethanakit T, Aruksakunwong O, Hannongbua S. Combined QM/MM mechanistic study of the acylation process in furin complexed with the H5N1 avian influenza virus hemagglutinin's cleavage site. Proteins 2009; 76:62-71. [PMID: 19089976 DOI: 10.1002/prot.22318] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Combined quantum mechanical/molecular mechanical (QM/MM) techniques have been applied to investigate the detailed reaction mechanism of the first step of the acylation process by furin in which the cleavage site of the highly pathogenic avian influenza virus subtype H5N1 (HPH5) acts as its substrate. The energy profile shows a simultaneous mechanism, known as a concerted reaction, of the two subprocesses: the proton transfer from Ser368 to His194 and the nucleophilic attack on the carbonyl carbon of the scissile peptide of the HPH5 cleavage site with a formation of tetrahedral intermediate (INT). The calculated energy barrier for this reaction is 16.2 kcal.mol(-1) at QM/MM B3LYP/6-31+G*//PM3-CHARMM22 level of theory. Once the reaction proceeds, the ordering of the electrostatic stabilization by protein environment is of the enzyme-substrate < transition state < INT complexes. Asp153 was found to play the most important role in the enzymatic reaction by providing the highest degree of intermediate complex stabilization. In addition, the negatively charged carbonyl oxygen of INT is well stabilized by the oxyanion hole constructed by Asn295's carboxamide and Ser368's backbone.
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Affiliation(s)
- Thanyada Rungrotmongkol
- Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
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172
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Christophersen OA, Haug A. Why is the world so poorly prepared for a pandemic of hypervirulent avian influenza? MICROBIAL ECOLOGY IN HEALTH AND DISEASE 2009. [DOI: 10.1080/08910600600866544] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
| | - Anna Haug
- Norwegian University of Life Sciences, Ås, Norway
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Avian influenza and Newcastle disease viruses from northern pintail in Japan: Isolation, characterization and inter-annual comparisons during 2006–2008. Virus Res 2009; 143:44-52. [DOI: 10.1016/j.virusres.2009.02.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Revised: 02/25/2009] [Accepted: 02/26/2009] [Indexed: 11/23/2022]
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174
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Daum LT, Canas LC, Arulanandam BP, Niemeyer D, Valdes JJ, Chambers JP. Real-time RT-PCR assays for type and subtype detection of influenza A and B viruses. Influenza Other Respir Viruses 2009; 1:167-75. [PMID: 19432632 PMCID: PMC4634535 DOI: 10.1111/j.1750-2659.2007.00024.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Influenza viruses type A (H3N2 and H1N1 subtypes) and B are the most prevalently circulating human influenza viruses. However, an increase in several confirmed cases of high pathogenic H5N1 in humans has raised concerns of a potential pandemic underscoring the need for rapid, point of contact detection. In this report, we describe development and evaluation of ‘type,’ i.e., influenza virus A and B, and ‘subtype,’ i.e., H1, H3, and H5, specific, single‐step/reaction vessel format, real‐time RT‐PCR assays using total RNA from archived reference strains, shell‐vial cultured and uncultured primary (throat swab/nasal wash) clinical samples. The type A and B specific assays detected all 16 influenza type A viruses and both currently circulating influenza B lineages (Yamagata and Victoria), respectively. ‘Type’ and ‘subtype’ specific assays utilize one common set of thermocycling conditions, are specific and highly sensitive (detection threshold of approximately 100 target template molecules). All clinical specimens and samples were evaluated using both the unconventional portable Ruggedized Advanced Pathogen Identification Device (RAPID) and standard laboratory bench LightCycler instruments. These potentially field‐deployable assays could offer significant utility for rapid, point of care screening needs arising from a pandemic influenza outbreak.
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Affiliation(s)
- Luke T Daum
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX 78249, USA
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175
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Abstract
The respiratory tract is characterized by an extensive surface area that is in direct contact with the environment, posing a significant problem for effective immune surveillance. Yet most respiratory pathogens are quickly recognized and controlled by a coordinated response involving the innate and adaptive arms of the immune system. The investigation of pulmonary immunity to respiratory viruses during a primary infection has demonstrated that multiple innate and adaptive immune mechanisms are necessary for efficient antiviral responses, and the inhibition of any single mechanism can have disastrous consequences for the host. Furthermore, the investigation of recall responses in the lung has shown that protection from a secondary challenge infection is a complex and elegant process that occurs in distinct stages. In this review, we discuss recent advances that describe the roles of individual components during primary and secondary responses to respiratory virus infections and how these discoveries have added to our understanding of antiviral immunity in the lung.
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176
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Infection and replication of avian influenza H5N1 virus in an infected human. Virus Genes 2009; 39:76-80. [PMID: 19444601 PMCID: PMC7101767 DOI: 10.1007/s11262-009-0365-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2008] [Accepted: 04/23/2009] [Indexed: 11/23/2022]
Abstract
The highly pathogenic avian influenza H5N1 viruses usually cause severe diseases and high mortality in infected humans. However, the tissue tropism and underlying pathogenesis of H5N1 virus infection in humans have not been clearly elucidated yet. In this study, an autopsy was conducted to better understand H5N1 virus distributions in tissues of infected humans, and whether H5N1 virus can replicate in extrapulmonary tissues. We found that the lungs had the higher viral load than the spleen, whereas no detectable viruses in tissues of heart, liver, kidney, large intestine, small intestine, or brain. Specifically, the viral load was higher in the left lung (7.1 log10 copies per ml) in relation to the right lung (5.7 log10 copies per ml), resulting in more severe pathological damage in the left lung, and lung tissues contained both positive- and negative-stranded viral RNA. However, there existed a low level of H5N1 viruses in the spleen (3.8 log10 copies per ml), with the absence of positive-stranded viral RNA. Our results indicate that replication of H5N1 viruses mainly occurs in the lungs, and the degree of lung damage is highly correlated with the viral load in the lungs. The low-load viruses in the spleen might be introduced through blood circulation or other ways.
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Herbert AS, Heffron L, Sundick R, Roberts PC. Incorporation of membrane-bound, mammalian-derived immunomodulatory proteins into influenza whole virus vaccines boosts immunogenicity and protection against lethal challenge. Virol J 2009; 6:42. [PMID: 19393093 PMCID: PMC2679740 DOI: 10.1186/1743-422x-6-42] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Accepted: 04/24/2009] [Indexed: 12/30/2022] Open
Abstract
Background Influenza epidemics continue to cause morbidity and mortality within the human population despite widespread vaccination efforts. This, along with the ominous threat of an avian influenza pandemic (H5N1), demonstrates the need for a much improved, more sophisticated influenza vaccine. We have developed an in vitro model system for producing a membrane-bound Cytokine-bearing Influenza Vaccine (CYT-IVAC). Numerous cytokines are involved in directing both innate and adaptive immunity and it is our goal to utilize the properties of individual cytokines and other immunomodulatory proteins to create a more immunogenic vaccine. Results We have evaluated the immunogenicity of inactivated cytokine-bearing influenza vaccines using a mouse model of lethal influenza virus challenge. CYT-IVACs were produced by stably transfecting MDCK cell lines with mouse-derived cytokines (GM-CSF, IL-2 and IL-4) fused to the membrane-anchoring domain of the viral hemagglutinin. Influenza virus replication in these cell lines resulted in the uptake of the bioactive membrane-bound cytokines during virus budding and release. In vivo efficacy studies revealed that a single low dose of IL-2 or IL-4-bearing CYT-IVAC is superior at providing protection against lethal influenza challenge in a mouse model and provides a more balanced Th1/Th2 humoral immune response, similar to live virus infections. Conclusion We have validated the protective efficacy of CYT-IVACs in a mammalian model of influenza virus infection. This technology has broad applications in current influenza virus vaccine development and may prove particularly useful in boosting immune responses in the elderly, where current vaccines are minimally effective.
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Affiliation(s)
- Andrew S Herbert
- Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, Virginia Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24060, USA.
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178
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Minimal molecular constraints for respiratory droplet transmission of an avian-human H9N2 influenza A virus. Proc Natl Acad Sci U S A 2009; 106:7565-70. [PMID: 19380727 DOI: 10.1073/pnas.0900877106] [Citation(s) in RCA: 182] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pandemic influenza requires interspecies transmission of an influenza virus with a novel hemagglutinin (HA) subtytpe that can adapt to its new host through either reassortment or point mutations and transmit by aerosolized respiratory droplets. Two previous pandemics of 1957 and 1968 resulted from the reassortment of low pathogenic avian viruses and human subtypes of that period; however, conditions leading to a pandemic virus are still poorly understood. Given the endemic situation of avian H9N2 influenza with human-like receptor specificity in Eurasia and its occasional transmission to humans and pigs, we wanted to determine whether an avian-human H9N2 reassortant could gain respiratory transmission in a mammalian animal model, the ferret. Here we show that following adaptation in the ferret, a reassortant virus carrying the surface proteins of an avian H9N2 in a human H3N2 backbone can transmit efficiently via respiratory droplets, creating a clinical infection similar to human influenza infections. Minimal changes at the protein level were found in this virus capable of respiratory droplet transmission. A reassortant virus expressing only the HA and neuraminidase (NA) of the ferret-adapted virus was able to account for the transmissibility, suggesting that currently circulating avian H9N2 viruses require little adaptation in mammals following acquisition of all human virus internal genes through reassortment. Hemagglutinin inhibition (HI) analysis showed changes in the antigenic profile of the virus, which carries profound implications for vaccine seed stock preparation against avian H9N2 influenza. This report illustrates that aerosolized respiratory transmission is not exclusive to current human H1, H2, and H3 influenza subtypes.
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Calligari PA, Kneller GR, Giansanti A, Ascenzi P, Porrello A, Bocedi A. Inhibition of viral group-1 and group-2 neuraminidases by oseltamivir: A comparative structural analysis by the ScrewFit algorithm. Biophys Chem 2009; 141:117-23. [DOI: 10.1016/j.bpc.2009.01.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Revised: 01/08/2009] [Accepted: 01/08/2009] [Indexed: 11/28/2022]
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Abstract
Influenza has been long absent from the list of infectious diseases considered as possibilities in dogs and cats. With the discovery that avian influenza H5N1 can infect cats and dogs, and the appearance of canine influenza H3N8, small animal veterinarians have an important role to play in detection of influenza virus strains that may become zoonotic. Small animal veterinarians must educate staff and clients about influenza to improve understanding as to when and where influenza infection is possible, and to avert unreasonable fears.
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Affiliation(s)
- Emily Beeler
- Los Angeles County Department of Public Health, Veterinary Public Health and Rabies Control Program, 7601 East Imperial Highway, Building 700, Room 94A, Downey, CA 90242, USA.
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181
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Hall JS, Bentler KT, Landolt G, Elmore SA, Minnis RB, Campbell TA, Barras SC, Root JJ, Pilon J, Pabilonia K, Driscoll C, Slate D, Sullivan H, McLean RG. Influenza infection in wild raccoons. Emerg Infect Dis 2009; 14:1842-8. [PMID: 19046505 PMCID: PMC2634612 DOI: 10.3201/eid1412.071371] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Raccoons (Procyon lotor) are common, widely distributed animals that frequently come into contact with wild waterfowl, agricultural operations, and humans. Serosurveys showed that raccoons are exposed to avian influenza virus. We found antibodies to a variety of influenza virus subtypes (H10N7, H4N6, H4N2, H3, and H1) with wide geographic variation in seroprevalence. Experimental infection studies showed that raccoons become infected with avian and human influenza A viruses, shed and transmit virus to virus-free animals, and seroconvert. Analyses of cellular receptors showed that raccoons have avian and human type receptors with a similar distribution as found in human respiratory tracts. The potential exists for co-infection of multiple subtypes of influenza virus with genetic reassortment and creation of novel strains of influenza virus. Experimental and field data indicate that raccoons may play an important role in influenza disease ecology and pose risks to agriculture and human health.
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Affiliation(s)
- Jeffrey S Hall
- US Department of Agriculture, National Wildlife Research Center, Fort Collins, Colorado 53711, USA.
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182
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Abstract
Proteolytic activation of the hemagglutinin (HA) protein is indispensable for influenza virus infectivity, and the tissue expression of the responsible cellular proteases impacts viral tropism and pathogenicity. The HA protein critically contributes to the exceptionally high pathogenicity of the 1918 influenza virus, but the mechanisms underlying cleavage activation of the 1918 HA have not been characterized. The neuraminidase (NA) protein of the 1918 influenza virus allows trypsin-independent growth in canine kidney cells (MDCK). However, it is at present unknown if the 1918 NA, like the NA of the closely related strain A/WSN/33, facilitates HA cleavage activation by recruiting the proprotease plasminogen. Moreover, it is not known which pulmonary proteases activate the 1918 HA. We provide evidence that NA-dependent, trypsin-independent cleavage activation of the 1918 HA is cell line dependent and most likely plasminogen independent since the 1918 NA failed to recruit plasminogen and neither exogenous plasminogen nor the presence of the A/WSN/33 NA promoted efficient cleavage of the 1918 HA. The transmembrane serine protease TMPRSS4 was found to be expressed in lung tissue and was shown to cleave the 1918 HA. Accordingly, coexpression of the 1918 HA with TMPRSS4 or the previously identified HA-processing protease TMPRSS2 allowed trypsin-independent infection by pseudotypes bearing the 1918 HA, indicating that these proteases might support 1918 influenza virus spread in the lung. In summary, we show that the previously reported 1918 NA-dependent spread of the 1918 influenza virus is a cell line-dependent phenomenon and is not due to plasminogen recruitment by the 1918 NA. Moreover, we provide evidence that TMPRSS2 and TMPRSS4 activate the 1918 HA by cleavage and therefore may promote viral spread in lung tissue.
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183
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Hickman D, Hossain MJ, Song H, Araya Y, Solórzano A, Perez DR. An avian live attenuated master backbone for potential use in epidemic and pandemic influenza vaccines. J Gen Virol 2009; 89:2682-2690. [PMID: 18931063 PMCID: PMC2886961 DOI: 10.1099/vir.0.2008/004143-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The unprecedented emergence in Asia of multiple avian influenza virus (AIV) subtypes with a broad host range poses a major challenge in the design of vaccination strategies that are both effective and available in a timely manner. The present study focused on the protective effects of a genetically modified AIV as a source for the preparation of vaccines for epidemic and pandemic influenza. It has previously been demonstrated that a live attenuated AIV based on the internal backbone of influenza A/Guinea fowl/Hong Kong/WF10/99 (H9N2), called WF10att, is effective at protecting poultry species against low- and high-pathogenicity influenza strains. More importantly, this live attenuated virus provided effective protection when administered in ovo. In order to characterize the WF10att backbone further for use in epidemic and pandemic influenza vaccines, this study evaluated its protective effects in mice. Intranasal inoculation of modified attenuated viruses in mice provided adequate protective immunity against homologous lethal challenges with both the wild-type influenza A/WSN/33 (H1N1) and A/Vietnam/1203/04 (H5N1) viruses. Adequate heterotypic immunity was also observed in mice vaccinated with modified attenuated viruses carrying H7N2 surface proteins. The results presented in this report suggest that the internal genes of a genetically modified AIV confer similar protection in a mouse model and thus could be used as a master donor strain for the generation of live attenuated vaccines for epidemic and pandemic influenza.
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Affiliation(s)
- Danielle Hickman
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, 8075 Greenmead Drive, College Park, MD 20742-3711, USA
| | - Md Jaber Hossain
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, 8075 Greenmead Drive, College Park, MD 20742-3711, USA
| | - Haichen Song
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, 8075 Greenmead Drive, College Park, MD 20742-3711, USA
| | - Yonas Araya
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, 8075 Greenmead Drive, College Park, MD 20742-3711, USA
| | - Alicia Solórzano
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, 8075 Greenmead Drive, College Park, MD 20742-3711, USA
| | - Daniel R Perez
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, 8075 Greenmead Drive, College Park, MD 20742-3711, USA
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184
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Abstract
Influenza is a zoonotic viral disease that represents a health and economic threat to both humans and animals worldwide. Swine influenza (SI) was first recognized clinically in pigs in the Midwestern U.S., in 1918, coinciding with the human influenza pandemic known as the Spanish flu. Since that time SI has remained of importance to the swine industry throughout the world. In this review, the epidemiology of swine influenza virus (SIV) infection in North American pigs is described in detail. The first 80 years of SI remained relatively static, whereas the last decade has become dynamic with the establishment of many emerging subtypes. With the increasing number of novel subtypes and genetic variants, the control of SI has become increasingly difficult and innovative strategies to combat this economically important zoonotic disease are critical. Therefore, protective immune responses against influenza virus infections as well as new paradigms of vaccine development in pigs are discussed in the review. It is expected that the dynamic evolutionary changes of SIVs in North American pigs will continue, making currently available prophylactic approaches of limited use to control the spread and economic losses associated with this important swine pathogen.
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Affiliation(s)
- Amy L Vincent
- Virus and Prion Diseases of Livestock Research Unit, National Animal Disease Center, USDA-ARS, Ames, Iowa 50010, USA
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185
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Abstract
In this chapter, we will review the development of and clinical experience with the currently licensed seasonal live attenuated influenza vaccines (LAIV) and preclinical studies of H5, H7, and H9 live attenuated pandemic influenza vaccine candidates. Vectored vaccine approaches will not be reviewed in this chapter. Experience with seasonal influenza vaccination has demonstrated the safety and efficacy of LAIV in both children and adults; moreover, cross-protection among antigenically distinct viruses within the same subtype may be induced by LAIV. While clinical studies and further characterization of the immunologic response to avian influenza viruses are still needed, the experience with seasonal LAIV underscores the potential of live attenuated vaccines to play an important role in the event of a pandemic.
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Affiliation(s)
- Grace L Chen
- Laboratory of Infectious Diseases, NIAID, NIH, Building 33, 3E 13C.2, 33 North Drive, MSC 3203, Bethesda, MD 20892-3203, USA
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186
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Abstract
Pandemics of influenza emerge from the aquatic bird reservoir, adapt to humans, modify their severity, and cause seasonal influenza. The catastrophic Spanish H1N1 virus may have obtained all of its eight gene segments from the avian reservoir, whereas the Asian H2N2 and the Hong Kong H3N2 pandemics emerged by reassortment between the circulating human virus and an avian H2 or H3 donor. Of the 16 hemagglutinin subtypes, the H2, H5, H6, H7, and H9 viruses are considered to have pandemic potential. While this chapter focuses on the evolution of the Asian highly pathogenic (HP) H5N1 influenza virus, other subtypes are also considered. The unique features of the HP H5N1 viruses that have devastated the domestic poultry of Eurasia are discussed. Although they transmit poorly to humans, they continue to kill more than 60% of infected persons. It is unknown whether HP H5N1 will acquire human pandemic status; if it does not, another subtype eventually will do so, for a future influenza pandemic is inevitable.
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187
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Wang W, Ren P, Mardi S, Hou L, Tsai C, Chan KH, Cheng P, Sheng J, Buchy P, Sun B, Toyoda T, Lim W, Peiris JSM, Zhou P, Deubel V. design of multiplexed detection assays for identification of avian influenza a virus subtypes pathogenic to humans by SmartCycler real-time reverse transcription-PCR. J Clin Microbiol 2009; 47:86-92. [PMID: 18971359 PMCID: PMC2620859 DOI: 10.1128/jcm.01090-08] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Revised: 08/13/2008] [Accepted: 10/13/2008] [Indexed: 11/20/2022] Open
Abstract
Influenza A virus (IAV) epidemics are the result of human-to-human or poultry-to-human transmission. Tracking seasonal outbreaks of IAV and other avian influenza virus (AIV) subtypes that can infect humans, aquatic and migratory birds, poultry, and pigs is essential for epidemiological surveillance and outbreak alerts. In this study, we performed four real-time reverse transcription-PCR (rRT-PCR) assays for identification of the IAV M and hemagglutinin (HA) genes from six known AIVs infecting pigs, birds, and humans. IAV M1 gene-positive samples tested by single-step rRT-PCR and a fluorogenic Sybr green I detection system were further processed for H5 subtype identification by using two-primer-set multiplex and Sybr green I rRT-PCR assays. H5 subtype-negative samples were then tested with either a TaqMan assay for subtypes H1 and H3 or a TaqMan assay for subtypes H2, H7, and H9 and a beacon multiplex rRT-PCR identification assay. The four-tube strategy was able to detect 10 RNA copies of the HA genes of subtypes H1, H2, H3, H5, and H7 and 100 RNA copies of the HA gene of subtype H9. At least six H5 clades of H5N1 viruses isolated in Southeast Asia and China were detected by that test. Using rRT-PCR assays for the M1 and HA genes in 202 nasopharyngeal swab specimens from children with acute respiratory infections, we identified a total of 39 samples positive for the IAV M1 gene and subtypes H1 and H3. When performed with a portable SmartCycler instrument, the assays offer an efficient, flexible, and reliable platform for investigations of IAV and AIV in remote hospitals and in the field.
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Affiliation(s)
- Wei Wang
- Chinese Academy of Sciences, Institut Pasteur of Shanghai, Shanghai Institute of Biological Sciences, 411 Hefei Road, 200025 Shanghai, People's Republic of China
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188
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Live attenuated influenza viruses containing NS1 truncations as vaccine candidates against H5N1 highly pathogenic avian influenza. J Virol 2008; 83:1742-53. [PMID: 19073731 DOI: 10.1128/jvi.01920-08] [Citation(s) in RCA: 182] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Due to the high mortality associated with recent, widely circulating strains of H5N1 influenza virus in poultry, the recurring introduction of H5N1 viruses from birds to humans, and the difficulties in H5N1 eradication by elimination of affected flocks, an effective vaccine against HPAI (highly pathogenic avian influenza) is highly desirable. Using reverse genetics, a set of experimental live attenuated vaccine strains based on recombinant H5N1 influenza virus A/Viet Nam/1203/04 was generated. Each virus was attenuated through expression of a hemagglutinin protein in which the polybasic cleavage site had been removed. Viruses were generated which possessed a full-length NS1 or a C-terminally truncated NS1 protein of 73, 99, or 126 amino acids. Viruses with each NS genotype were combined with a PB2 polymerase gene which carried either a lysine or a glutamic acid at position 627. We predicted that glutamic acid at position 627 of PB2 would attenuate the virus in mammalian hosts, thus increasing the safety of the vaccine. All recombinant viruses grew to high titers in 10-day-old embryonated chicken eggs but were attenuated in mammalian cell culture. Induction of high levels of beta interferon by all viruses possessing truncations in the NS1 protein was demonstrated by interferon bioassay. The viruses were each found to be highly attenuated in a mouse model. Vaccination with a single dose of any virus conferred complete protection from death upon challenge with a mouse lethal virus expressing H5N1 hemagglutinin and neuraminidase proteins. In a chicken model, vaccination with a single dose of a selected virus encoding the NS1 1-99 protein completely protected chickens from lethal challenge with homologous HPAI virus A/Viet Nam/1203/04 (H5N1) and provided a high level of protection from a heterologous virus, A/egret/Egypt/01/06 (H5N1). Thus, recombinant influenza A/Viet Nam/1203/04 viruses attenuated through the introduction of mutations in the hemagglutinin, NS1, and PB2 coding regions display characteristics desirable for live attenuated vaccines and hold potential as vaccine candidates in poultry as well as in mammalian hosts.
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189
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Chen Y, Xu F, Fan X, Luo H, Ge S, Zheng Q, Xia N, Chen H, Guan Y, Zhang J. Evaluation of a rapid test for detection of H5N1 avian influenza virus. J Virol Methods 2008; 154:213-5. [DOI: 10.1016/j.jviromet.2008.08.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Revised: 08/14/2008] [Accepted: 08/20/2008] [Indexed: 11/29/2022]
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190
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Somphou P, Takano T, Nakamura K. Cohabitation with farm animals in urban households with and without occupational farm work: associations between participation in educational activities and good hygiene practices in at-risk households cohabiting with farm animals. Environ Health Prev Med 2008; 13:322-31. [PMID: 19568892 PMCID: PMC2698226 DOI: 10.1007/s12199-008-0046-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Accepted: 07/22/2008] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVES This study was performed to investigate patterns of cohabitation with farm animals in urban households in Vientiane, Lao People's Democratic Republic, with regard to animal-to-human disease transmission. We also investigated the association between participation in hygiene-related educational activities and good hygiene practices in households with or without cohabitation with animals. METHODS A survey regarding cohabitation with animals, socioeconomic characteristics and participation in educational activities was conducted among 1,497 households randomly sampled from urban districts of Vientiane in 2001. Rates of satisfactory performance of recommended good hygiene practices according to a program commencing in 1996 were compared among households cohabiting with animals with or without participation in educational activities (reference group). RESULTS Even among households not engaged in agriculture as a major source of income, 54.4, 34.9, 7.9, 3.1 and 35.7% cohabited with chickens, ducks, cattle, buffaloes and dogs, respectively. The percentage of households fulfilling the recommendations for good hygiene practices was 56.7%. The rates of satisfactory hygiene practices among households participating in health education and cohabitating with chickens, ducks or cattle were greater than those in the reference group (OR = 1.7, 95%CI = 1.2, 2.3; OR = 2.0, 95%CI = 1.3, 3.0; OR = 2.3, 95%CI = 1.0, 4.9) regardless of socioeconomic factors. Households cohabiting with animals showed poorer rates of satisfactory hygiene practices than those without animals. CONCLUSIONS Cohabitation with farm animals is common in urban Vientiane regardless of household involvement in agriculture. Further effort is required to improve hygiene conditions, despite some positive effects of health education even in households cohabiting with animals.
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Affiliation(s)
- Phoupasong Somphou
- Health Promotion Section, Division of Public Health, Graduate School of Tokyo Medical and Dental University, Tokyo, Japan
- Vientiane Municipality Health Department, Vientiane, Lao People’s Democratic Republic
| | - Takehito Takano
- Health Promotion Section, Division of Public Health, Graduate School of Tokyo Medical and Dental University, Tokyo, Japan
| | - Keiko Nakamura
- International Health Section, Division of Public Health, Graduate School of Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo, 113-8519 Japan
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191
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Abstract
Avian influenza A virus A/teal/HK/W312/97 (H6N1) possesses seven gene segments that are highly homologous to those of highly pathogenic human influenza H5N1 viruses, suggesting that a W312-like H6N1 virus might have been involved in the generation of the A/HK/97 H5N1 viruses. The continuous circulation and reassortment of influenza H6 subtype viruses in birds highlight the need to develop an H6 vaccine to prevent potential influenza pandemics caused by the H6 viruses. Based on the serum antibody cross-reactivity data obtained from 14 different H6 viruses from Eurasian and North American lineages, A/duck/HK/182/77, A/teal/HK/W312/97, and A/mallard/Alberta/89/85 were selected to produce live attenuated H6 candidate vaccines. Each of the H6 vaccine strains is a 6:2 reassortant ca virus containing HA and NA gene segments from an H6 virus and the six internal gene segments from cold-adapted A/Ann Arbor/6/60 (AA ca), the master donor virus that is used to make live attenuated influenza virus FluMist (intranasal) vaccine. All three H6 vaccine candidates exhibited phenotypic properties of temperature sensitivity (ts), ca, and attenuation (att) conferred by the internal gene segments from AA ca. Intranasal administration of a single dose of the three H6 ca vaccine viruses induced neutralizing antibodies in mice and ferrets and fully protected mice and ferrets from homologous wild-type (wt) virus challenge. Among the three H6 vaccine candidates, the A/teal/HK/W312/97 ca virus provided the broadest cross-protection against challenge with three antigenically distinct H6 wt viruses. These data support the rationale for further evaluating the A/teal/HK/W312/97 ca vaccine in humans.
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192
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Greger M. The Human/Animal Interface: Emergence and Resurgence of Zoonotic Infectious Diseases. Crit Rev Microbiol 2008; 33:243-99. [DOI: 10.1080/10408410701647594] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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193
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VanDalen KK, Anderson TD, Killian ML, Pedersen JC, Franklin AB, Piaggio AJ. Increased detection of influenza A H16 in the United States. Arch Virol 2008; 153:1981-3. [PMID: 18825483 DOI: 10.1007/s00705-008-0213-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Accepted: 09/05/2008] [Indexed: 11/29/2022]
Abstract
As a result of an US interagency avian influenza surveillance effort in wild birds, four isolates of influenza A viruses were initially identified as H7 by hemagglutination inhibition (HI) but subsequently identified as H16 through genetic sequence analysis. We report the development of internal primers for amplification and cycle-sequencing of the full-length H16 gene, increased detection of H16 within the US, and possible steric inhibition or cross-reaction between H7 and H16 antigens during the conventional HI assay. The latter could have critical implications for poultry operations if H16 viruses are detected and mistakenly reported as H7 viruses.
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Affiliation(s)
- Kaci K VanDalen
- US Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Fort Collins, CO 80521, USA.
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194
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Luo M, Tao P, Li J, Zhou S, Guo D, Pan Z. Immunization with plasmid DNA encoding influenza A virus nucleoprotein fused to a tissue plasminogen activator signal sequence elicits strong immune responses and protection against H5N1 challenge in mice. J Virol Methods 2008; 154:121-7. [PMID: 18789973 DOI: 10.1016/j.jviromet.2008.08.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2008] [Revised: 08/12/2008] [Accepted: 08/15/2008] [Indexed: 11/16/2022]
Abstract
DNA vaccination is an effective means of eliciting both humoral and cellular immunity. Most of influenza vaccines targeted at hemagglutinin (HA) show efficient immunogenicity for protecting subjects against influenza virus infection. However, major antigenic variations of HA may facilitate the virus in developing resistance against such vaccines. DNA vaccines encoding conserved antigens protect animals against diverse viral subtypes, but their potency requires further improvement. In the present study, a DNA vaccine encoding the conserved nucleoprotein (NP) with a tissue plasminogen activator (tPA) signal sequence (ptPAs/NP) was generated, and immune responses were examined in vaccinated mice. A higher level of NP expression and secretion was observed in lysates and supernatants of the cells transfected with ptPAs/NP when compared to a plasmid encoding the wild-type full-length NP (pflNP). Immunofluorescence studies showed the cytoplasmic localization of the NP protein expressed from ptPAs/NP, but not from pflNP. In mice, the ptPAs/NP vaccine elicited higher levels of the NP-specific IgG and CD8(+) T cell-stimulating responses than that of pflNP. Vaccination with ptPAs/NP efficiently cleared the homologous H5N1 influenza virus in the infected lungs and induced partial cross-protection against heterologous, highly pathogenic H5N1 strains in mice. Our results may contribute to the development of protective immunity against diverse, highly pathogenic H5N1 virus subtypes.
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Affiliation(s)
- Mengcheng Luo
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
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195
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Hoelscher M, Gangappa S, Zhong W, Jayashankar L, Sambhara S. Vaccines against epidemic and pandemic influenza. Expert Opin Drug Deliv 2008; 5:1139-57. [DOI: 10.1517/17425247.5.10.1139] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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196
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Avian influenza viruses detected by surveillance of waterfowl in Ireland during 2003–2007. Epidemiol Infect 2008; 137:464-72. [DOI: 10.1017/s0950268808001325] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
SUMMARYSpecimens for the detection of avian influenza virus (AIV) were collected from 1937 waterfowl on the Wexford Sloblands, a major wetland reserve in southeast Ireland, between January 2003 and September 2007. During the same period, 1404 waterfowl were sampled at other locations in Ireland. Specimens were tested either by virus isolation or real-time reverse transcriptase polymerase chain reaction (rtRT–PCR). A total of 32 isolates of AIV, comprising nine subtypes, was obtained from specimens from the Sloblands compared with just one isolate from elsewhere in Ireland. Samples from nine other waterfowl, five of which were from the Sloblands, tested positive for AIV by rtRT–PCR. Ecological factors are likely to have contributed to the higher detection rate of AIV at the Sloblands compared with the rest of Ireland. It was concluded that targeted surveillance at such sites is a cost-effective means of monitoring the circulation of new AIVs in waterfowl, whereas widespread opportunistic sampling is unproductive and wasteful of resources.
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197
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Bogomolni AL, Gast RJ, Ellis JC, Dennett M, Pugliares KR, Lentell BJ, Moore MJ. Victims or vectors: a survey of marine vertebrate zoonoses from coastal waters of the Northwest Atlantic. DISEASES OF AQUATIC ORGANISMS 2008; 81:13-38. [PMID: 18828560 PMCID: PMC5452619 DOI: 10.3354/dao01936] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Surveillance of zoonotic pathogens in marine birds and mammals in the Northwest Atlantic revealed a diversity of zoonotic agents. We found amplicons to sequences from Brucella spp., Leptospira spp., Giardia spp. and Cryptosporidium spp. in both marine mammals and birds. Avian influenza was detected in a harp seal and a herring gull. Routine aerobic and anaerobic culture showed a broad range of bacteria resistant to multiple antibiotics. Of 1460 isolates, 797 were tested for resistance, and 468 were resistant to one or more anti-microbials. 73% (341/468) were resistant to 1-4 drugs and 27% (128/468) resistant to 5-13 drugs. The high prevalence of resistance suggests that many of these isolates could have been acquired from medical and agricultural sources and inter-microbial gene transfer. Combining birds and mammals, 45% (63/141) of stranded and 8% (2/26) of by-caught animals in this study exhibited histopathological and/or gross pathological findings associated with the presence of these pathogens. Our findings indicate that marine mammals and birds in the Northwest Atlantic are reservoirs for potentially zoonotic pathogens, which they may transmit to beachgoers, fishermen and wildlife health personnel. Conversely, zoonotic pathogens found in marine vertebrates may have been acquired via contamination of coastal waters by sewage, run-off and agricultural and medical waste. In either case these animals are not limited by political boundaries and are therefore important indicators of regional and global ocean health.
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Affiliation(s)
- Andrea L. Bogomolni
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
| | - Rebecca J. Gast
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
| | - Julie C. Ellis
- Tufts University, Cummings School of Veterinary Medicine, 200 Westboro Road, North Grafton, Massachusetts 01536, USA
| | - Mark Dennett
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
| | - Katie R. Pugliares
- Cape Cod Stranding Network, a project of IFAW, 290 Summer Street, Yarmouthport, Massachusetts 02675, USA
| | - Betty J. Lentell
- National Marine Fisheries Service, Northeast Fisheries Observer Program, 166 Water Street, Woods Hole, Massachusetts 02543, USA
| | - Michael J. Moore
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
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198
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Wan H, Sorrell EM, Song H, Hossain MJ, Ramirez-Nieto G, Monne I, Stevens J, Cattoli G, Capua I, Chen LM, Donis RO, Busch J, Paulson JC, Brockwell C, Webby R, Blanco J, Al-Natour MQ, Perez DR. Replication and transmission of H9N2 influenza viruses in ferrets: evaluation of pandemic potential. PLoS One 2008; 3:e2923. [PMID: 18698430 PMCID: PMC2500216 DOI: 10.1371/journal.pone.0002923] [Citation(s) in RCA: 232] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Accepted: 07/14/2008] [Indexed: 12/04/2022] Open
Abstract
H9N2 avian influenza A viruses are endemic in poultry of many Eurasian countries and have caused repeated human infections in Asia since 1998. To evaluate the potential threat of H9N2 viruses to humans, we investigated the replication and transmission efficiency of H9N2 viruses in the ferret model. Five wild-type (WT) H9N2 viruses, isolated from different avian species from 1988 through 2003, were tested in vivo and found to replicate in ferrets. However these viruses achieved mild peak viral titers in nasal washes when compared to those observed with a human H3N2 virus. Two of these H9N2 viruses transmitted to direct contact ferrets, however no aerosol transmission was detected in the virus displaying the most efficient direct contact transmission. A leucine (Leu) residue at amino acid position 226 in the hemagglutinin (HA) receptor-binding site (RBS), responsible for human virus-like receptor specificity, was found to be important for the transmission of the H9N2 viruses in ferrets. In addition, an H9N2 avian-human reassortant virus, which contains the surface glycoprotein genes from an H9N2 virus and the six internal genes of a human H3N2 virus, showed enhanced replication and efficient transmission to direct contacts. Although no aerosol transmission was observed, the virus replicated in multiple respiratory tissues and induced clinical signs similar to those observed with the parental human H3N2 virus. Our results suggest that the establishment and prevalence of H9N2 viruses in poultry pose a significant threat for humans.
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Affiliation(s)
- Hongquan Wan
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
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199
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Alvarez AC, Brunck MEG, Boyd V, Lai R, Virtue E, Chen W, Bletchly C, Heine HG, Barnard R. A broad spectrum, one-step reverse-transcription PCR amplification of the neuraminidase gene from multiple subtypes of influenza A virus. Virol J 2008; 5:77. [PMID: 18613963 PMCID: PMC2483269 DOI: 10.1186/1743-422x-5-77] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Accepted: 07/09/2008] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The emergence of high pathogenicity strains of Influenza A virus in a variety of human and animal hosts, with wide geographic distribution, has highlighted the importance of rapid identification and subtyping of the virus for outbreak management and treatment. Type A virus can be classified into subtypes according to the viral envelope glycoproteins, hemagglutinin and neuraminidase. Here we review the existing specificity and amplification of published primers to subtype neuraminidase genes and describe a new broad spectrum primer pair that can detect all 9 neuraminidase subtypes. RESULTS Bioinformatic analysis of 3,337 full-length influenza A neuraminidase segments in the NCBI database revealed semi-conserved regions not previously targeted by primers. Two degenerate primers with M13 tags, NA8F-M13 and NA10R-M13 were designed from these regions and used to generate a 253 bp cDNA product. One-step RT-PCR testing was successful in 31/32 (97%) cases using a touchdown protocol with RNA from over 32 different cultured influenza A virus strains representing the 9 neuraminidase subtypes. Frozen blinded clinical nasopharyngeal aspirates were also assayed and were mostly of subtype N2. The region amplified was direct sequenced and then used in database searches to confirm the identity of the template RNA. The RT-PCR fragment generated includes one of the mutation sites related to oseltamivir resistance, H274Y. CONCLUSION Our one-step RT-PCR assay followed by sequencing is a rapid, accurate, and specific method for detection and subtyping of different neuraminidase subtypes from a range of host species and from different geographical locations.
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Affiliation(s)
| | - Marion EG Brunck
- Biochip Innovations Pty Ltd., 8 Mile Plains, Queensland, Australia
| | - Victoria Boyd
- CSIRO livestock Industries, Australian Animal Health Laboratory (AAHL), Geelong, Vic, Australia
| | - Richard Lai
- Biochip Innovations Pty Ltd., 8 Mile Plains, Queensland, Australia
| | - Elena Virtue
- CSIRO livestock Industries, Australian Animal Health Laboratory (AAHL), Geelong, Vic, Australia
- Australian Biosecurity Cooperative Research Centre for Emerging Infectious Disease, The University of Queensland, St. Lucia, Queensland, Australia
| | - Wenbin Chen
- Pathology Queensland, Central Laboratory, Herston Hospitals Campus, Herston, Queensland, Australia
| | - Cheryl Bletchly
- Pathology Queensland, Central Laboratory, Herston Hospitals Campus, Herston, Queensland, Australia
| | - Hans G Heine
- CSIRO livestock Industries, Australian Animal Health Laboratory (AAHL), Geelong, Vic, Australia
| | - Ross Barnard
- Biochip Innovations Pty Ltd., 8 Mile Plains, Queensland, Australia
- School of Molecular and Microbial Sciences, The University of Queensland, St. Lucia, Queensland, Australia
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200
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Smallman-Raynor M, Cliff AD. The Geographical Spread of Avian Influenza A (H5N1): Panzootic Transmission (December 2003–May 2006), Pandemic Potential, and Implications. ACTA ACUST UNITED AC 2008. [DOI: 10.1080/00045600802098958] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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