scholarly journals Generation of a Highly Pathogenic Avian Influenza A Virus from an Avirulent Field Isolate by Passaging in Chickens

2001 ◽  
Vol 75 (9) ◽  
pp. 4439-4443 ◽  
Author(s):  
Toshihiro Ito ◽  
Hideo Goto ◽  
Eiji Yamamoto ◽  
Hiroko Tanaka ◽  
Mutsuko Takeuchi ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Field Isolate ◽  
Influenza Viruses ◽  
Highly Pathogenic ◽  
Avian Influenza A Virus ◽  
Highly Virulent ◽  
Type Sequence ◽  
Wild Waterfowl ◽  
Selection Of

ABSTRACT Highly virulent avian influenza viruses can arise from avirulent strains maintained in poultry, but evidence to support their generation from viruses in wild birds is lacking. The most likely mechanism for the acquisition of virulence by benign avian viruses is the introduction of mutations by error-prone RNA polymerase, followed by the selection of virulent viruses. To investigate whether this mechanism could apply to wild waterfowl, we studied an avirulent wild-swan virus that replicates poorly in chickens. After 24 consecutive passages by air sac inoculation, followed by five passages in chicken brain, the avirulent virus became highly pathogenic in chickens, producing a 100% mortality rate. Sequence analysis at the hemmaglutinin cleavage site of the original isolate revealed a typical avirulence type of sequence, R-E-T-R, which progressed incrementally to a typical virulence type of sequence, R-R-K-K-R, during repeated passages in chickens. These results demonstrate that avirulent viruses maintained in wild waterfowl in nature and bearing the consensus avirulence type sequence R-E-T-R have the potential to become highly pathogenic while circulating in chickens.

scholarly journals Comparison of the transmission characteristics of low and high pathogenicity avian influenza A virus (H5N2)

2003 ◽  
Vol 131 (2) ◽  
pp. 1003-1013 ◽  
Author(s):  
J. A. VAN DER GOOT ◽  
M. C. M. DE JONG ◽  
G. KOCH ◽  
M. VAN BOVEN
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Influenza Viruses ◽  
Infectious Period ◽  
Transmission Characteristics ◽  
Final Size ◽  
Highly Pathogenic ◽  
Avian Influenza A Virus ◽  
Previous Infection ◽  
Means Of Transmission

Low pathogenicity avian influenza A strains (LPAI) of the H5 and H7 type are noted for their ability to transform into highly pathogenic counterparts (HPAI). Here we compare the transmission characteristics in poultry of LPAI H5N2 (A/Chicken/Pennsylvania/83) and corresponding HPAI virus by means of transmission experiments. In the experiments, five inoculated animals are placed in a cage with five contact animals, and the infection chain is monitored by taking blood samples, and samples from the trachea and cloaca. The data are analysed by final size methods and a generalized linear model. The results show that HPAI virus is more infectious and induces a longer infectious period than LPAI. In fact, fully susceptible animals are invariably infected when confronted with HPAI virus and die within six days after infection. Animals previously infected with LPAI virus, on the other hand, survive an infection with HPAI virus or escape infection all together. This implies that a previous infection with LPAI virus effectively reduces susceptibility of the host to infection and decreases transmission of HPAI virus. We discuss the implications of these conclusions for the control and evolution of avian influenza viruses.

scholarly journals Protection and Virus Shedding of Falcons Vaccinated against Highly Pathogenic Avian Influenza A Virus (H5N1)

2007 ◽  
Vol 13 (11) ◽  
pp. 1667-1674 ◽  
Author(s):  
Michael Lierz ◽  
Hafez M. Hafez ◽  
Robert Klopfleisch ◽  
Dörte Lüschow ◽  
Christine Prusas ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A Virus ◽  
Influenza A ◽  
Highly Pathogenic Avian Influenza ◽  
Highly Pathogenic ◽  
Virus Shedding ◽  
Pathogenic Avian Influenza ◽  
Virus H5n1 ◽  
Avian Influenza A Virus

scholarly journals Molecular Basis for the Generation in Pigs of Influenza A Viruses with Pandemic Potential

1998 ◽  
Vol 72 (9) ◽  
pp. 7367-7373 ◽  
Author(s):  
Toshihiro Ito ◽  
J. Nelson S. S. Couceiro ◽  
Sørge Kelm ◽  
Linda G. Baum ◽  
Scott Krauss ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Influenza Viruses ◽  
Structural Basis ◽  
Human Populations ◽  
Influenza A Viruses ◽  
Human Virus ◽  
Surface Receptors ◽  
Virus Receptors ◽  
Avian Influenza A Virus

ABSTRACT Genetic and biologic observations suggest that pigs may serve as “mixing vessels” for the generation of human-avian influenza A virus reassortants, similar to those responsible for the 1957 and 1968 pandemics. Here we demonstrate a structural basis for this hypothesis. Cell surface receptors for both human and avian influenza viruses were identified in the pig trachea, providing a milieu conducive to viral replication and genetic reassortment. Surprisingly, with continued replication, some avian-like swine viruses acquired the ability to recognize human virus receptors, raising the possibility of their direct transmission to human populations. These findings help to explain the emergence of pandemic influenza viruses and support the need for continued surveillance of swine for viruses carrying avian virus genes.

scholarly journals Molecular Analysis of H7 Avian Influenza Viruses from Australia and New Zealand: Genetic Diversity and Relationships from 1976 to 2007

2010 ◽  
Vol 84 (19) ◽  
pp. 9957-9966 ◽  
Author(s):  
Dieter Bulach ◽  
Rebecca Halpin ◽  
David Spiro ◽  
Laura Pomeroy ◽  
Daniel Janies ◽  
...  
Keyword(s):  
New Zealand ◽  
Avian Influenza ◽  
Influenza A ◽  
Influenza Viruses ◽  
Full Genome Sequencing ◽  
Influenza A Viruses ◽  
Independent Evolution ◽  
Avian Influenza A Virus ◽  
Geographic Regions ◽  
Genetic Pool

ABSTRACT Full-genome sequencing of 11 Australian and 1 New Zealand avian influenza A virus isolate (all subtype H7) has enabled comparison of the sequences of each of the genome segments to those of other subtype H7 avian influenza A viruses. The inference of phylogenetic relationships for each segment has been used to develop a model of the natural history of these viruses in Australia. Phylogenetic analysis of the hemagglutinin segment indicates that the Australian H7 isolates form a monophyletic clade. This pattern is consistent with the long-term, independent evolution that is, in this instance, associated with geographic regions. On the basis of the analysis of the other H7 hemagglutinin sequences, three other geographic regions for which similar monophyletic clades have been observed were confirmed. These regions are Eurasia plus Africa, North America, and South America. Analysis of the neuraminidase sequences from the H7N1, H7N3, and H7N7 genomes revealed the same region-based relationships. This pattern of independent evolution of Australian isolates is supported by the results of analysis of each of the six remaining genomic segments. These results, in conjunction with the occurrence of five different combinations of neuraminidase subtypes (H7N2, H7N3, H7N4, H7N6, H7N7) among the 11 Australian isolates, suggest that the maintenance host(s) is nearly exclusively associated with Australia. The single lineage of Australian H7 hemagglutinin sequences, despite the occurrence of multiple neuraminidase types, suggests the existence of a genetic pool from which a variety of reassortants arise rather than the presence of a small number of stable viral clones. This pattern of evolution is likely to occur in each of the regions mentioned above.

scholarly journals Complete Coding Sequences of One H9 and Three H7 Low-Pathogenic Influenza Viruses Circulating in Wild Birds in Belgium, 2009 to 2012

2016 ◽  
Vol 4 (3) ◽  
Author(s):  
Steven Van Borm ◽  
Toon Rosseel ◽  
Sylvie Marché ◽  
Mieke Steensels ◽  
Didier Vangeluwe ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Illumina Sequencing ◽  
Viral Genome ◽  
Influenza A ◽  
Wild Bird ◽  
Influenza Viruses ◽  
Influenza A Viruses ◽  
Bird Population ◽  
Coding Sequences ◽  
Wild Waterfowl

The complete coding sequences of four avian influenza A viruses (two H7N7, one H7N1, and one H9N2) circulating in wild waterfowl in Belgium from 2009 to 2012 were determined using Illumina sequencing. All viral genome segments represent viruses circulating in the Eurasian wild bird population.

Identification of a Small Benzamide Inhibitor of Influenza Virus Using a Cell-Based Screening

Chemotherapy ◽  
2016 ◽  
Vol 61 (3) ◽  
pp. 159-166 ◽  
Author(s):  
Woo-Jin Shin ◽  
Ky-Youb Nam ◽  
Nam-Doo Kim ◽  
Sei-Hwan Kim ◽  
Kyoung-Tai No ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
H1n1 Influenza ◽  
Influenza Viruses ◽  
Global Pandemic ◽  
Lethal Infection ◽  
Avian Influenza A Virus ◽  
A Cell ◽  
Antiviral Activities

Background: The zoonotic transmission of highly pathogenic avian influenza viruses and the global pandemic of H1N1 influenza in 2009 signified the need for a wider coverage of therapeutic options for the control of influenza. Methods: An in-house compound library was screened using a cytopathic effect inhibition assay. Selected hits were then tested in vivo and used as a core skeleton for derivative synthesis. Results: The hit compound (BMD-2601505) was effective [50% effective concentration (EC50) of 60-70 μM] in reducing the death rate of cells infected with human influenza A and B viruses as well as avian influenza A virus. Furthermore, BMD-2601505 reduced the weight loss and increased the survival after lethal infection. The compound was further modified to enhance its antiviral potency. Results show that one derivative with bromobenzene moiety was most effective (EC50 of 22-37 μM) against the influenza viruses tested. Conclusion: We identified a small benzamide compound exhibiting antiviral activity against influenza viruses. The results warrant further evaluation of antiviral activities against drug-resistant influenza isolates.

scholarly journals Pathogenesis and Transmission Assessments of Two H7N8 Influenza A Viruses Recently Isolated from Turkey Farms in Indiana Using Mouse and Ferret Models

2016 ◽  
Vol 90 (23) ◽  
pp. 10936-10944 ◽  
Author(s):  
Xiangjie Sun ◽  
Jessica A. Belser ◽  
Joanna A. Pulit-Penaloza ◽  
Hui Zeng ◽  
Amanda Lewis ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Influenza Viruses ◽  
Avian Influenza Viruses ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza ◽  
Domestic Poultry ◽  
Commercial Turkey

ABSTRACTAvian influenza A H7 viruses have caused multiple outbreaks in domestic poultry throughout North America, resulting in occasional infections of humans in close contact with affected birds. In early 2016, the presence of H7N8 highly pathogenic avian influenza (HPAI) viruses and closely related H7N8 low-pathogenic avian influenza (LPAI) viruses was confirmed in commercial turkey farms in Indiana. These H7N8 viruses represent the first isolation of this subtype in domestic poultry in North America, and their virulence in mammalian hosts and the potential risk for human infection are largely unknown. In this study, we assessed the ability of H7N8 HPAI and LPAI viruses to replicatein vitroin human airway cells andin vivoin mouse and ferret models. Both H7N8 viruses replicated efficientlyin vitroandin vivo, but they exhibited substantial differences in disease severity in mammals. In mice, while the H7N8 LPAI virus largely remained avirulent, the H7N8 HPAI virus exhibited greater infectivity, virulence, and lethality. Both H7N8 viruses replicated similarly in ferrets, but only the H7N8 HPAI virus caused moderate weight loss, lethargy, and mortality. The H7N8 LPAI virus displayed limited transmissibility in ferrets placed in direct contact with an inoculated animal, while no transmission of H7N8 HPAI virus was detected. Our results indicate that the H7N8 avian influenza viruses from Indiana are able to replicate in mammals and cause severe disease but with limited transmission. The recent appearance of H7N8 viruses in domestic poultry highlights the need for continued influenza surveillance in wild birds and close monitoring of the potential risk to human health.IMPORTANCEH7 influenza viruses circulate in wild birds in the United States, but when the virus emerges in domestic poultry populations, the frequency of human exposure and the potential for human infections increases. An H7N8 highly pathogenic avian influenza (HPAI) virus and an H7N8 low-pathogenic avian influenza (LPAI) virus were recently isolated from commercial turkey farms in Indiana. To determine the risk that these influenza viruses pose to humans, we assessed their pathogenesis and transmissionin vitroand in mammalian models. We found that the H7N8 HPAI virus exhibited enhanced virulence, and although transmission was only observed with the H7N8 LPAI virus, the ability of this H7 virus to transmit in a mammalian host and quickly evolve to a more virulent strain is cause for concern. Our findings offer important insight into the potential for emerging H7 avian influenza viruses to acquire the ability to cause disease and transmit among mammals.

Newcastle Disease and Avian Influenza A Virus in Wild Waterfowl in South Africa

2000 ◽  
Vol 44 (3) ◽  
pp. 655 ◽  
Author(s):  
S. Pfitzer ◽  
D. J. Verwoerd ◽  
G. H. Gerdes ◽  
A. E. Labuschagne ◽  
A. Erasmus ◽  
...  
Keyword(s):  
South Africa ◽  
Avian Influenza ◽  
Influenza A Virus ◽  
Newcastle Disease ◽  
Influenza A ◽  
Avian Influenza A Virus ◽  
Wild Waterfowl

scholarly journals Newly Emergent Highly Pathogenic H5N9 Subtype Avian Influenza A Virus

2015 ◽  
Vol 89 (17) ◽  
pp. 8806-8815 ◽  
Author(s):  
Yang Yu ◽  
Xingbo Wang ◽  
Tao Jin ◽  
Hailong Wang ◽  
Weiying Si ◽  
...  
Keyword(s):  
Public Health ◽  
Avian Influenza ◽  
Influenza A ◽  
Mortality Rates ◽  
The Novel ◽  
Reassortant Virus ◽  
Highly Pathogenic ◽  
Live Bird Markets ◽  
Avian Influenza A Virus ◽  
Live Bird

ABSTRACTThe novel H7N9 avian influenza virus (AIV) was demonstrated to cause severe human respiratory infections in China. Here, we examined poultry specimens from live bird markets linked to human H7N9 infection in Hangzhou, China. Metagenomic sequencing revealed mixed subtypes (H5, H7, H9, N1, N2, and N9). Subsequently, AIV subtypes H5N9, H7N9, and H9N2 were isolated. Evolutionary analysis showed that the hemagglutinin gene of the novel H5N9 virus originated from A/Muscovy duck/Vietnam/LBM227/2012 (H5N1), which belongs to clade 2.3.2.1. The neuraminidase gene of the novel H5N9 virus originated from human-infective A/Hangzhou/1/2013 (H7N9). The six internal genes were similar to those of other H5N1, H7N9, and H9N2 virus strains. The virus harbored the PQRERRRKR/GL motif characteristic of highly pathogenic AIVs at the HA cleavage site. Receptor-binding experiments demonstrated that the virus binds α-2,3 sialic acid but not α-2,6 sialic acid. Identically, pathogenicity experiments also showed that the virus caused low mortality rates in mice. This newly isolated H5N9 virus is a highly pathogenic reassortant virus originating from H5N1, H7N9, and H9N2 subtypes. Live bird markets represent a potential transmission risk to public health and the poultry industry.IMPORTANCEThis investigation confirms that the novel H5N9 subtype avian influenza A virus is a reassortant strain originating from H5N1, H7N9, and H9N2 subtypes and is totally different from the H5N9 viruses reported before. The novel H5N9 virus acquired a highly pathogenic H5 gene and an N9 gene from human-infecting subtype H7N9 but caused low mortality rates in mice. Whether this novel H5N9 virus will cause human infections from its avian host and become a pandemic subtype is not known yet. It is therefore imperative to assess the risk of emergence of this novel reassortant virus with potential transmissibility to public health.

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