The Character of Influenza Virus the H7 Subtype and Alert to Novel Influenza Virus H7N9 Subtype Virus

Abstract Background Information regarding comparison of the environmental prevalence of avian influenza virus (AIVs), before and after massive poultry vaccinations, is limited. Our study aimed to detect differences in the prevalence of AIVs type A and subtypes H5, H7, and H9 before and after the September 2017 massive poultry vaccination, across different sampling places and types. Methods We collected 55 130 environmental samples from 11 cities in Zhejiang Province (China) between March 2013 and December 2018. Multivariate logistic regression analyses were conducted to determine the prevalence of AIV type A and subtypes H5, H7, and H9 across different sampling places and types, before and after massive poultry vaccination. Results After the vaccination, contamination risk of AIV type A (adjusted odds ratio [aOR] = 1.08; 95% confidence interval [CI], 1.03–1.14) and subtype H9 (aOR = 1.58; 95% CI, 1.48–1.68) increased, and that of subtype H7 (aOR = 0.12; 95% CI, 0.10–0.14) decreased. Statistically significant decreased risk for H7 subtype contamination and increased risk for H9 subtype contamination were observed in backyard poultry flocks, live poultry markets, and slaughtering/processing plants. Swabs from poultry cages and slaughtering tables showed a statistically significant increased risk for H5 subtype contamination. The prevalence of H7 subtype decreased statistically significantly, whereas that of H9 subtype increased across the 5 sample types (poultry cages swabs, slaughtering table swabs, poultry feces, poultry drinking water, and poultry sewage). Conclusions Despite the sharp decrease in H7 subtype prevalence, reduction measures for AIV circulation are still imperative, given the high type A prevalence and the increase in H9 subtype contamination across different sampling places and types.

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Universal influenza virus vaccines: what can we learn from the human immune response following exposure to H7 subtype viruses?

Frontiers of Medicine ◽

10.1007/s11684-017-0602-z ◽

2017 ◽

Vol 11 (4) ◽

pp. 471-479 ◽

Cited By ~ 6

Author(s):

Daniel Stadlbauer ◽

Raffael Nachbagauer ◽

Philip Meade ◽

Florian Krammer

Keyword(s):

Immune Response ◽

Influenza Virus ◽

Human Immune Response ◽

Human Immune ◽

H7 Subtype

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Acquisition of a Polybasic Hemagglutinin Cleavage Site by a Low-Pathogenic Avian Influenza Virus Is Not Sufficient for Immediate Transformation into a Highly Pathogenic Strain

Journal of Virology ◽

10.1128/jvi.02649-08 ◽

2009 ◽

Vol 83 (11) ◽

pp. 5864-5868 ◽

Cited By ~ 56

Author(s):

Olga Stech ◽

Jutta Veits ◽

Siegfried Weber ◽

Daniela Deckers ◽

Diana Schröer ◽

...

Keyword(s):

Influenza Virus ◽

Avian Influenza ◽

Avian Influenza Virus ◽

Cleavage Site ◽

Influenza Viruses ◽

Avirulent Strain ◽

Wild Type ◽

Highly Pathogenic ◽

Pathogenic Avian Influenza ◽

H7 Subtype

ABSTRACT Highly pathogenic avian influenza viruses (HPAIV) differ from all other strains by a polybasic cleavage site in their hemagglutinin. All these HPAIV share the H5 or H7 subtype. In order to investigate whether the acquisition of a polybasic cleavage site by an avirulent avian influenza virus strain with a hemagglutinin other than H5 or H7 is sufficient for immediate transformation into an HPAIV, we adapted the hemagglutinin cleavage site of A/Duck/Ukraine/1/1963 (H3N8) to that of the HPAIV A/Chicken/Italy/8/98 (H5N2), A/Chicken/HongKong/220/97 (H5N1), or A/Chicken/Germany/R28/03 (H7N7) and generated the recombinant wild-type and cleavage site mutants. In contrast to the wild type, multicycle replication of these mutants in tissue culture was demonstrated by positive plaque assays and viral multiplication in the absence of exogenous trypsin. Therefore, in vitro all cleavage site mutants resemble an HPAIV. However, in chicken they did not exhibit high pathogenicity, although they could be reisolated from cloacal swabs to some extent, indicating enhanced replication in vivo. These results demonstrate that beyond the polybasic hemagglutinin cleavage site, the virulence of HPAIV in chicken is based on additional pathogenicity determinants within the hemagglutinin itself or in the other viral proteins. Taken together, these observations support the notion that acquisition of a polybasic hemagglutinin cleavage site by an avirulent strain with a non-H5/H7 subtype is only one among several alterations necessary for evolution into an HPAIV.

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Development of a monoclonal antibody‐based antigen capture enzyme‐linked immunosorbent assay for detection of H7N9 subtype avian influenza virus

Journal of Medical Virology ◽

10.1002/jmv.26292 ◽

2020 ◽

Author(s):

Fan Yang ◽

Yixin Xiao ◽

Fumin Liu ◽

Hangping Yao ◽

Nanping Wu ◽

...

Keyword(s):

Monoclonal Antibody ◽

Influenza Virus ◽

Avian Influenza ◽

Avian Influenza Virus ◽

Immunosorbent Assay ◽

Enzyme Linked Immunosorbent Assay ◽

Antigen Capture ◽

H7n9 Subtype

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Computational approach for predicting the conserved B-cell epitopes of hemagglutinin H7 subtype influenza virus

Experimental and Therapeutic Medicine ◽

10.3892/etm.2016.3636 ◽

2016 ◽

Vol 12 (4) ◽

pp. 2439-2446 ◽

Cited By ~ 6

Author(s):

Xiangyu Wang ◽

Qi Sun ◽

Zhonghua Ye ◽

Ying Hua ◽

Na Shao ◽

...

Keyword(s):

Influenza Virus ◽

B Cell ◽

Computational Approach ◽

B Cell Epitopes ◽

H7 Subtype

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AS03-adjuvanted H7N9 inactivated split virion vaccines induce cross-reactive and protective responses in ferrets

npj Vaccines ◽

10.1038/s41541-021-00299-3 ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

Daniel Stadlbauer ◽

Leon de Waal ◽

Edith Beaulieu ◽

Shirin Strohmeier ◽

Edwin J. B. Veldhuis Kroeze ◽

...

Keyword(s):

Case Fatality ◽

Influenza Viruses ◽

Health Concern ◽

Post Challenge ◽

The North ◽

H7n9 Subtype ◽

Challenge Study ◽

Eurasian Lineage ◽

Antibody Titers ◽

H7 Subtype

AbstractHuman infections with avian H7N9 subtype influenza viruses are a major public health concern and vaccines against H7N9 are urgently needed for pandemic preparedness. In early 2013, novel H7N9 influenza viruses emerged in China that caused about 1600 human cases of infection with a high associated case fatality rate. In this study, two H7N9 split virion vaccines with or without AS03 adjuvant were tested in the naive ferret model. Serological analyses demonstrated that homologous hemagglutination inhibition and microneutralization antibody titers were detectable in the ferrets after the first immunization with the AS03-adjuvanted vaccines that were further boosted by the second immunization. In addition, heterologous antibody titers against older H7 subtype viruses of the North American lineage (H7N7, H7N3) and newer H7 subtype viruses of the Eurasian lineage (H7N9) were detected in the animals receiving the AS03-adjuvanted vaccines. Animals receiving two immunizations of the AS03-adjuvanted vaccines were protected from weight loss and fever in the homologous challenge study and had no detectable virus in throat or lung samples. In addition, microscopic examination post-challenge showed animals immunized with the AS03-adjuvanted vaccines had the least signs of lung injury and inflammation, consistent with the greater relative efficacy of the adjuvanted vaccines. In conclusion, this study demonstrated that the AS03-adjuvanted H7N9 vaccines elicited high levels of homologous and heterologous antibodies and protected against H7N9 virus damage post-challenge.

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