scholarly journals Efficacy of Oseltamivir Therapy in Ferrets Inoculated with Different Clades of H5N1 Influenza Virus

2007 ◽  
Vol 51 (4) ◽  
pp. 1414-1424 ◽  
Author(s):  
Elena A. Govorkova ◽  
Natalia A. Ilyushina ◽  
David A. Boltz ◽  
Alan Douglas ◽  
Neziha Yilmaz ◽  
...  
Keyword(s):  
H5n1 Virus ◽  
Direct Sequencing ◽  
Influenza Viruses ◽  
Upper Respiratory Tract ◽  
Virus Inoculation ◽  
Highly Pathogenic ◽  
H5n1 Influenza ◽  
Homologous Virus ◽  
Ha1 Gene ◽  
Pathogenic H5n1

ABSTRACT Highly pathogenic H5N1 influenza viruses have infected an increasing number of humans in Asia, with high mortality rates and the emergence of multiple distinguishable clades. It is not known whether antiviral drugs that are effective against contemporary human influenza viruses will be effective against systemically replicating viruses, such as these pathogens. Therefore, we evaluated the use of the neuraminidase (NA) inhibitor oseltamivir for early postexposure prophylaxis and for treatment in ferrets exposed to representatives of two clades of H5N1 virus with markedly different pathogenicities in ferrets. Ferrets were protected from lethal infection with the A/Vietnam/1203/04 (H5N1) virus by oseltamivir (5 mg/kg of body weight/day) given 4 h after virus inoculation, but higher daily doses (25 mg/kg) were required for treatment when it was initiated 24 h after virus inoculation. For the treatment of ferrets inoculated with the less pathogenic A/Turkey/15/06 (H5N1) virus, 10 mg/kg/day of oseltamivir was sufficient to reduce the lethargy of the animals, significantly inhibit inflammation in the upper respiratory tract, and block virus spread to the internal organs. Importantly, all ferrets that survived the initial infection were rechallenged with homologous virus after 21 days and were completely protected from infection. Direct sequencing of the NA or HA1 gene segments in viruses isolated from ferret after treatment showed no amino acid substitutions known to cause drug resistance in conserved residues. Thus, early oseltamivir treatment is crucial for protection against highly pathogenic H5N1 viruses and the higher dose may be needed for the treatment of more virulent viruses.

scholarly journals Competitive Fitness of Oseltamivir-Sensitive and -Resistant Highly Pathogenic H5N1 Influenza Viruses in a Ferret Model

2010 ◽  
Vol 84 (16) ◽  
pp. 8042-8050 ◽  
Author(s):  
Elena A. Govorkova ◽  
Natalia A. Ilyushina ◽  
Bindumadhav M. Marathe ◽  
Jennifer L. McClaren ◽  
Robert G. Webster
Keyword(s):  
Influenza Viruses ◽  
Viral Fitness ◽  
Upper Respiratory Tract ◽  
Drug Pressure ◽  
Highly Pathogenic ◽  
Enzyme Active Site ◽  
Enzymatic Function ◽  
H5n1 Influenza ◽  
Novel Approach ◽  
Pathogenic H5n1

ABSTRACT The fitness of oseltamivir-resistant highly pathogenic H5N1 influenza viruses has important clinical implications. We generated recombinant human A/Vietnam/1203/04 (VN; clade 1) and A/Turkey/15/06 (TK; clade 2.2) influenza viruses containing the H274Y neuraminidase (NA) mutation, which confers resistance to NA inhibitors, and compared the fitness levels of the wild-type (WT) and resistant virus pairs in ferrets. The VN-H274Y and VN-WT viruses replicated to similar titers in the upper respiratory tract (URT) and caused comparable disease signs, and none of the animals survived. On days 1 to 3 postinoculation, disease signs caused by oseltamivir-resistant TK-H274Y virus were milder than those caused by TK-WT virus, and all animals survived. We then studied fitness by using a novel approach. We coinoculated ferrets with different ratios of oseltamivir-resistant and -sensitive H5N1 viruses and measured the proportion of clones in day-6 nasal washes that contained the H274Y NA mutation. Although the proportion of VN-H274Y clones increased consistently, that of TK-H274Y virus decreased. Mutations within NA catalytic (R292K) and framework (E119A/K, I222L, H274L, and N294S) sites or near the NA enzyme active site (V116I, I117T/V, Q136H, K150N, and A250T) emerged spontaneously (without drug pressure) in both pairs of viruses. The NA substitutions I254V and E276A could exert a compensatory effect on the fitness of VN-H274Y and TK-H274Y viruses. NA enzymatic function was reduced in both drug-resistant H5N1 viruses. These results show that the H274Y NA mutation affects the fitness of two H5N1 influenza viruses differently. Our novel method of assessing viral fitness accounts for both virus-host interactions and virus-virus interactions within the host.

scholarly journals Host Genetic Variation Affects Resistance to Infection with a Highly Pathogenic H5N1 Influenza A Virus in Mice

2009 ◽  
Vol 83 (20) ◽  
pp. 10417-10426 ◽  
Author(s):  
Adrianus C. M. Boon ◽  
Jennifer deBeauchamp ◽  
Anna Hollmann ◽  
Jennifer Luke ◽  
Malak Kotb ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
H5n1 Virus ◽  
Lethal Dose ◽  
Influenza Virus Infection ◽  
Virus Titer ◽  
Influenza Viruses ◽  
Highly Pathogenic ◽  
H5n1 Influenza ◽  
Pathogenic H5n1

ABSTRACT Despite the prevalence of H5N1 influenza viruses in global avian populations, comparatively few cases have been diagnosed in humans. Although viral factors almost certainly play a role in limiting human infection and disease, host genetics most likely contribute substantially. To model host factors in the context of influenza virus infection, we determined the lethal dose of a highly pathogenic H5N1 virus (A/Hong Kong/213/03) in C57BL/6J and DBA/2J mice and identified genetic elements associated with survival after infection. The lethal dose in these hosts varied by 4 logs and was associated with differences in replication kinetics and increased production of proinflammatory cytokines CCL2 and tumor necrosis factor alpha in susceptible DBA/2J mice. Gene mapping with recombinant inbred BXD strains revealed five loci or Qivr (quantitative trait loci for influenza virus resistance) located on chromosomes 2, 7, 11, 15, and 17 associated with resistance to H5N1 virus. In conjunction with gene expression profiling, we identified a number of candidate susceptibility genes. One of the validated genes, the hemolytic complement gene, affected virus titer 7 days after infection. We conclude that H5N1 influenza virus-induced pathology is affected by a complex and multigenic host component.

scholarly journals Selection of H5N1 Influenza Virus PB2 during Replication in Humans

2009 ◽  
Vol 83 (10) ◽  
pp. 5278-5281 ◽  
Author(s):  
Quynh Mai Le ◽  
Yuko Sakai-Tagawa ◽  
Makoto Ozawa ◽  
Mustumi Ito ◽  
Yoshihiro Kawaoka
Keyword(s):  
Amino Acids ◽  
Protein A ◽  
Direct Analysis ◽  
Influenza Viruses ◽  
Upper Respiratory Tract ◽  
Virus Propagation ◽  
Highly Pathogenic ◽  
H5n1 Influenza ◽  
Respiratory Tract Viruses ◽  
Pathogenic H5n1

ABSTRACT Highly pathogenic H5N1 influenza viruses continue to cause concern, even though currently circulating strains are not efficiently transmitted among humans. For efficient transmission, amino acid changes in viral proteins may be required. Here, we examined the amino acids at positions 627 and 701 of the PB2 protein. A direct analysis of the viral RNAs of H5N1 viruses in patients revealed that these amino acids contribute to efficient virus propagation in the human upper respiratory tract. Viruses grown in culture or eggs did not always reflect those in patients. These results emphasize the importance of the direct analysis of original specimens.

scholarly journals Are Ducks Contributing to the Endemicity of Highly Pathogenic H5N1 Influenza Virus in Asia?

2005 ◽  
Vol 79 (17) ◽  
pp. 11269-11279 ◽  
Author(s):  
K. M. Sturm-Ramirez ◽  
D. J. Hulse-Post ◽  
E. A. Govorkova ◽  
J. Humberd ◽  
P. Seiler ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Virus Disease ◽  
Influenza Viruses ◽  
H5n1 Influenza Virus ◽  
Highly Pathogenic ◽  
Main Site ◽  
H5n1 Influenza ◽  
Pathogenic H5n1 ◽  
Virus Isolates

ABSTRACT Wild waterfowl are the natural reservoir of all influenza A viruses, and these viruses are usually nonpathogenic in these birds. However, since late 2002, H5N1 outbreaks in Asia have resulted in mortality among waterfowl in recreational parks, domestic flocks, and wild migratory birds. The evolutionary stasis between influenza virus and its natural host may have been disrupted, prompting us to ask whether waterfowl are resistant to H5N1 influenza virus disease and whether they can still act as a reservoir for these viruses. To better understand the biology of H5N1 viruses in ducks and attempt to answer this question, we inoculated juvenile mallards with 23 different H5N1 influenza viruses isolated in Asia between 2003 and 2004. All virus isolates replicated efficiently in inoculated ducks, and 22 were transmitted to susceptible contacts. Viruses replicated to higher levels in the trachea than in the cloaca of both inoculated and contact birds, suggesting that the digestive tract is not the main site of H5N1 influenza virus replication in ducks and that the fecal-oral route may no longer be the main transmission path. The virus isolates' pathogenicities varied from completely nonpathogenic to highly lethal and were positively correlated with tracheal virus titers. Nevertheless, the eight virus isolates that were nonpathogenic in ducks replicated and transmitted efficiently to naïve contacts, suggesting that highly pathogenic H5N1 viruses causing minimal signs of disease in ducks can propagate silently and efficiently among domestic and wild ducks in Asia and that they represent a serious threat to human and veterinary public health.

scholarly journals High Level of Genetic Compatibility between Swine-Origin H1N1 and Highly Pathogenic Avian H5N1 Influenza Viruses

2010 ◽  
Vol 84 (20) ◽  
pp. 10918-10922 ◽  
Author(s):  
Cássio Pontes Octaviani ◽  
Makoto Ozawa ◽  
Shinya Yamada ◽  
Hideo Goto ◽  
Yoshihiro Kawaoka
Keyword(s):  
Influenza Virus ◽  
H5n1 Virus ◽  
Human Lung ◽  
Cultured Cells ◽  
Influenza Viruses ◽  
Compatibility Studies ◽  
Genetic Compatibility ◽  
Highly Pathogenic ◽  
H5n1 Influenza ◽  
High Level

Reassortment is an important mechanism for the evolution of influenza viruses. Here, we coinfected cultured cells with the pandemic swine-origin influenza virus (S-OIV) and a contemporary H5N1 virus and found that these two viruses have high genetic compatibility. Studies of human lung cell lines indicated that some reassortants had better growth kinetics than their parental viruses. We conclude that reassortment between these two viruses can occur and could create pandemic H5N1 viruses.

scholarly journals Molecular Evolution of H6 Influenza Viruses from Poultry in Southeastern China: Prevalence of H6N1 Influenza Viruses Possessing Seven A/Hong Kong/156/97 (H5N1)-Like Genes in Poultry

2002 ◽  
Vol 76 (2) ◽  
pp. 507-516 ◽  
Author(s):  
P. S. Chin ◽  
E. Hoffmann ◽  
R. Webby ◽  
R. G. Webster ◽  
Y. Guan ◽  
...  
Keyword(s):  
Amino Acids ◽  
Hong Kong ◽  
H5n1 Virus ◽  
Influenza Pandemic ◽  
Influenza Viruses ◽  
Evolutionary Analysis ◽  
Human Pathogens ◽  
Species Barrier ◽  
H5n1 Influenza ◽  
Pathogenic H5n1

ABSTRACT The A/teal/Hong Kong/W312/97 (H6N1) influenza virus and the human H5N1 and H9N2 influenza viruses possess similar genes encoding internal proteins, suggesting that H6N1 viruses could become novel human pathogens. The molecular epidemiology and evolution of H6 influenza viruses were characterized by antigenic and genetic analyses of 29 H6 influenza viruses isolated from 1975 to 1981 and 1997 to 2000. Two distinct groups were identified on the basis of their antigenic characteristics. Phylogenetic analysis revealed that all H6N1 viruses isolated from terrestrial poultry in 1999 and 2000 are closely related to A/teal/Hong Kong/W312/97 (H6N1), and the nucleotide sequences of these viruses and of A/Hong Kong/156/97 (H5N1) were more than 96% homologous. The hemagglutinin (HA) of the 1999 and 2000 terrestrial viruses does not have multiple basic amino acids at the site of cleavage of HA1 to HA2; however, a unique insertion of aspartic acid in HA1 between positions 144 and 145 (H3 numbering) was found. The neuraminidase of these terrestrial H6N1 viruses has a deletion of 19 amino acids characteristic of A/Hong Kong/156/97 (H5N1). Evolutionary analysis suggested that these H6N1 viruses coevolved with A/quail/Hong Kong/G1/97-like H9N2 viruses and became more adapted to terrestrial poultry. These terrestrial 1999 and 2000 A/teal/Hong Kong/W312/97 (H6N1)-like viruses, along with the H9N2 viruses, could have been involved in the genesis of the pathogenic H5N1 influenza viruses of 1997. The presence of H6N1 viruses in poultry markets in Hong Kong that possess seven of the eight genes of the A/Hong Kong/156/97 (H5N1) virus raises the following fundamental questions relevant to influenza pandemic preparedness: could the pathogenic H5N1 virus reemerge and could the H6N1 viruses directly cross the species barrier to mammals?

scholarly journals Epitope Mapping of the Hemagglutinin Molecule of a Highly Pathogenic H5N1 Influenza Virus by Using Monoclonal Antibodies

2007 ◽  
Vol 81 (23) ◽  
pp. 12911-12917 ◽  
Author(s):  
Nikolai V. Kaverin ◽  
Irina A. Rudneva ◽  
Elena A. Govorkova ◽  
Tatyana A. Timofeeva ◽  
Aleksandr A. Shilov ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Amino Acid ◽  
H5n1 Virus ◽  
Antigenic Site ◽  
H5n1 Influenza Virus ◽  
Highly Pathogenic ◽  
H5n1 Influenza ◽  
Antigenic Sites ◽  
Escape Mutants ◽  
Pathogenic H5n1

ABSTRACT We mapped the hemagglutinin (HA) antigenic epitopes of a highly pathogenic H5N1 influenza virus on the three-dimensional HA structure by characterizing escape mutants of a recombinant virus containing A/Vietnam/1203/04 (H5N1) ΔHA and neuraminidase genes in the genetic background of A/Puerto Rico/8/34 (H1N1) virus. The mutants were selected with a panel of eight anti-HA monoclonal antibodies (MAbs), seven to A/Vietnam/1203/04 (H5N1) virus and one to A/Chicken/Pennsylvania/8125/83 (H5N2) virus, and the mutants’ HA genes were sequenced. The amino acid changes suggested three MAb groups: four MAbs reacted with the complex epitope comprising parts of the antigenic site B of H3 HA and site Sa of H1 HA, two MAbs reacted with the epitope corresponding to the antigenic site A in H3 HA, and two MAbs displayed unusual behavior: each recognized amino acid changes at two widely separate antigenic sites. Five changes were detected in amino acid residues not previously reported as changed in H5 escape mutants, and four others had substitutions not previously described. The HA antigenic structure differs substantially between A/Vietnam/1203/04 (H5N1) virus and the low-pathogenic A/Mallard/Pennsylvania/10218/84 (H5N2) virus we previously characterized (N. V. Kaverin et al., J. Gen. Virol. 83:2497-2505, 2002). The hemagglutination inhibition reactions of the MAbs with recent highly pathogenic H5N1 viruses were consistent with the antigenic-site amino acid changes but not with clades and subclades based on H5 phylogenetic analysis. These results provide information on the recognition sites of the MAbs widely used to study H5N1 viruses and demonstrate the involvement of the HA antigenic sites in the evolution of highly pathogenic H5N1 viruses, findings that can be critical for characterizing pathogenesis and vaccine design.

scholarly journals The current state of H5N1 vaccines and the use of the ferret model for influenza therapeutic and prophylactic development

2012 ◽  
Vol 6 (06) ◽  
pp. 465-469 ◽  
Author(s):  
David Banner ◽  
Alyson Ann Kelvin
Keyword(s):  
H5n1 Virus ◽  
Influenza Viruses ◽  
Current Status ◽  
Global Public Health ◽  
Highly Pathogenic ◽  
Current State ◽  
Vaccine Testing ◽  
Pathogenic H5n1 ◽  
Influenza H5n1 ◽  
H5n1 Vaccine

Highly pathogenic avian influenza H5N1 is a threat to global public health as a natural pandemic causing agent but has recently been considered a bioterrorism concern.  The evolving view of the H5N1 virus necessitates the re-evaluation of the current status of H5N1 therapeutics and prophylactics, in particular the preparation of viable H5N1 vaccination strategies as well as the use of ferrets in influenza research.  Here the highly pathogenic H5N1 virus dilemma is discussed in context with the current H5N1 vaccine status and the use of the ferret model.  Previously, the development of various H5N1 vaccine platforms have been attempted, many of them tested in the ferret model, including vector vaccines, adjuvant vaccines, DNA vaccines, and reverse engineered vaccines. Moreover, as ferrets are a superlative animal model for influenza investigation and vaccine testing, it is imperative that this model is recognized for its uses in prophylactic development and not only as an agent for creating transmissible influenza viruses.  Elucidating the ferret immune response and creating ferret immune reagents remain important goals in conjunction with the development and manufacture of H5N1 vaccines.  In summary, an efficacious H5N1 vaccine is urgently needed and the ferret model remains an appropriate model for its development.

scholarly journals Apoptotic and Early Innate Immune Responses to PB1-F2 Protein of Influenza A Viruses Belonging to Different Subtypes in Human Lung Epithelial A549 Cells

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Gunisha Pasricha ◽  
Sanjay Mukherjee ◽  
Alok K. Chakrabarti
Keyword(s):  
Inflammatory Response ◽  
Influenza A ◽  
H5n1 Virus ◽  
A549 Cells ◽  
Terminal Region ◽  
Influenza Viruses ◽  
Influenza A Viruses ◽  
Highly Pathogenic ◽  
Lung Epithelial ◽  
Pathogenic H5n1

PB1-F2 is a multifunctional protein and contributes to the pathogenicity of influenza A viruses. PB1-F2 is known to have strain and cell specific functions. In this study we have investigated the apoptotic and inflammatory responses of PB1-F2 protein from influenza viruses of diverse pathogenicities in A549 lung epithelial cells. Overexpression of PB1-F2 resulted in apoptosis and heightened inflammatory response in A549 cells. Comparison revealed that the response varied with each subtype. PB1-F2 protein from highly pathogenic H5N1 virus induced least apoptosis but maximum inflammatory response. Results indicated that apoptosis was mediated through death receptor ligands TNFα and TRAIL via Caspase 8 activation. Significant induction of cytokines/chemokines CXCL10, CCL5, CCL2, IFNα, and IL-6 was noted in A549 cells transfected with PB1-F2 gene construct of 2008 West Bengal H5N1 virus (H5N1-WB). On the contrary, PB1-F2 construct from 2007 highly pathogenic H5N1 isolate (H5N1-M) with truncated N-terminal region did not evoke as exuberant inflammatory response as the other H5N1-WB with full length PB1-F2, signifying the importance of N-terminal region of PB1-F2. Sequence analysis revealed that PB1-F2 proteins derived from different influenza viruses varied at multiple amino acid positions. The secondary structure prediction showed each of the PB1-F2 proteins had distinct helix-loop-helix structure. Thus, our data substantiate the notion that the contribution of PB1-F2 to influenza pathogenicity is greatly strain specific and involves multiple host factors. This data demonstrates that PB1-F2 protein of influenza A virus, when expressed independently is minimally apoptotic and strongly influences the early host response in A549 cells.

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