scholarly journals Deletion of the C-terminal ESEV domain of NS1 does not affect the replication of a low-pathogenic avian influenza virus H7N1 in ducks and chickens

2013 ◽  
Vol 94 (1) ◽  
pp. 50-58 ◽  
Author(s):  
Sébastien M. Soubies ◽  
Thomas W. Hoffmann ◽  
Guillaume Croville ◽  
Thibaut Larcher ◽  
Mireille Ledevin ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Virus Replication ◽  
Reverse Genetics ◽  
Binding Motif ◽  
Pathogenic Avian Influenza ◽  
C Terminus ◽  
Efficient Replication ◽  
Pathogenic Avian Influenza Virus ◽  
Low Pathogenic Avian Influenza

Highly pathogenic avian influenza (HPAI) H7N1 viruses caused a series of epizootics in Italy between 1999 and 2001. The emergence of these HPAI viruses coincided with the deletion of the six amino acids R225VESEV230 at the C terminus of NS1. In order to assess how the truncation of NS1 affected virus replication, we used reverse genetics to generate a wild-type low-pathogenic avian influenza (LPAI) H7N1 virus with a 230aa NS1 (H7N1230) and a mutant virus with a truncated NS1 (H7N1224). The 6aa truncation had no impact on virus replication in duck or chicken cells in vitro. The H7N1230 and H7N1224 viruses also replicated to similar levels and induced similar immune responses in ducks or chickens. No significant histological lesions were detected in infected ducks, regardless of the virus inoculated. However, in chickens, the H7N1230 virus induced a more severe interstitial pneumonia than did the H7N1224 virus. These findings indicate that the C-terminal extremity of NS1, including the PDZ-binding motif ESEV, is dispensable for efficient replication of an LPAI virus in ducks and chickens, even though it may increase virulence in chickens, as revealed by the intensity of the histological lesions.

Interference between low pathogenic avian influenza H9N2 and avirulent Newcastle diseases viruses in embryonated Specific Pathogen-Free chicken eggs

2021 ◽  
Vol 1 (2) ◽  
pp. 7-10
Author(s):  
Amal Essalah-Bennani ◽  
Asma Fagrach ◽  
Abderrazak El Khantour ◽  
Ouafaa Fassi Fihri ◽  
Moncef Bouzouaia ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Virus Replication ◽  
Model Assessment ◽  
Specific Pathogen Free ◽  
Pathogenic Avian Influenza ◽  
Specific Pathogen ◽  
Pathogenic Avian Influenza Virus ◽  
Low Pathogenic Avian Influenza

Co-infection with low pathogenic avian influenza virus (LPAIV) H9N2 and Newcastle disease virus (NDV) has become a worrying concern for the poultry industry. The problem arises when the hidden virus influences the replication of another suspected virus. Subsequently, misdiagnosis of the actual cause may be ended up as a source of contamination for the other healthy flocks by the spread of the covered-up virus. In this preliminary study, we determined the potential impact of concurrent infection with H9N2 and avirulent NDV (Lasota) on the virus replication in Specific Pathogen-Free embryonated chicken egg (SPF-ECE) model. Assessment of the potential interference phenomena was carried out based on embryonic lesions, mortalities, and virus replication using real-time PCR. Our results showed that H9N2 interferes with LaSota growth, regardless of which infection occurred first. Our obtained preliminary results are a call for scientists to study the interference between LPAIV H9N2 and NDV both in-vivo and in-vitro in more detail.

scholarly journals Insertion of a Multibasic Cleavage Motif into the Hemagglutinin of a Low-Pathogenic Avian Influenza H6N1 Virus Induces a Highly Pathogenic Phenotype

2010 ◽  
Vol 84 (16) ◽  
pp. 7953-7960 ◽  
Author(s):  
Vincent J. Munster ◽  
Eefje J. A. Schrauwen ◽  
Emmie de Wit ◽  
Judith M. A. van den Brand ◽  
Theo M. Bestebroer ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Virus Replication ◽  
Influenza A ◽  
Virus Genotype ◽  
Specific Nature ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza ◽  
Low Pathogenic Avian Influenza

ABSTRACT The highly pathogenic avian influenza (HPAI) virus phenotype is restricted to influenza A viruses of the H5 and H7 hemagglutinin (HA) subtypes. To obtain more information on the apparent subtype-specific nature of the HPAI virus phenotype, a low-pathogenic avian influenza (LPAI) H6N1 virus was generated, containing an HPAI H5 RRRKKR↓G multibasic cleavage site (MBCS) motif in HA (the downward arrow indicates the site of cleavage). This insertion converted the LPAI virus phenotype into an HPAI virus phenotype in vitro and in vivo. The H6N1 virus with an MBCS displayed in vitro characteristics similar to those of HPAI H5 viruses, such as cleavage of HA0 (the HA protein of influenza A virus initially synthesized as a single polypeptide precursor) and virus replication in the absence of exogenous trypsin. Studies of chickens confirmed the HPAI phenotype of the H6N1 virus with an MBCS, with an intravenous pathogenicity index of 1.4 and systemic virus replication upon intranasal inoculation, the hallmarks of HPAI viruses. This study provides evidence that the subtype-specific nature of the emergence of HPAI viruses is not at the molecular, structural, or functional level, since the introduction of an MBCS resulted in a fully functional virus with an HPAI virus genotype and phenotype.

scholarly journals Reverse genetics of influenza viruses

2006 ◽  
Vol 27 (4) ◽  
pp. 153
Author(s):  
Glenn A Marsh
Keyword(s):  
Influenza Virus ◽  
Avian Influenza ◽  
Virus Replication ◽  
Reverse Genetics ◽  
Highly Pathogenic Avian Influenza ◽  
Influenza Viruses ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza ◽  
Pathogenic Avian Influenza Virus ◽  
Virus Replication Cycle

Reverse genetics for generation of influenza viruses is a powerful tool allowing for the direct manipulation of the genome of viruses. It has the potential to allow for the generation of safer and more immunogenic vaccines and for a better understanding of the virus replication cycle. Reverse genetics is essential tool for producing a vaccine against the highly pathogenic avian influenza virus.

Opposite outcomes of the within-host competition between highly and low pathogenic H5N8 avian influenza viruses in chickens compared to ducks

2021 ◽  
Author(s):  
Pierre Bessière ◽  
Thomas Figueroa ◽  
Amelia Coggon ◽  
Charlotte Foret-Lucas ◽  
Alexandre Houffschmitt ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Reverse Genetics ◽  
Highly Pathogenic Avian Influenza ◽  
Viral Evolution ◽  
Influenza Viruses ◽  
Poultry Production ◽  
Avian Influenza Viruses ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza ◽  
Low Pathogenic Avian Influenza

Highly pathogenic avian influenza viruses (HPAIV) emerge from low pathogenic avian influenza viruses (LPAIV) through the introduction of basic amino acids at the hemagglutinin (HA) cleavage site. Following viral evolution, the newly formed HPAIV likely represents a minority variant within the index host, predominantly infected with the LPAIV precursor. Using reverse-genetics engineered H5N8 viruses differing solely at the HA cleavage, we tested the hypothesis that the interaction between the minority HPAIV and the majority LPAIV could modulate the risk of HPAIV emergence and that the nature of the interaction could depend on the host species. In chickens, we observed that the H5N8 LP increased H5N8 HP replication and pathogenesis. By contrast, the H5N8 LP antagonized H5N8 HP replication and pathogenesis in ducks. Ducks mounted a more potent antiviral innate immune response than chickens against the H5N8 LP , which correlated with H5N8 HP inhibition. These data provide experimental evidence that HPAIV may be more likely to emerge in chickens than in ducks and underscore the importance of within-host viral variants interactions in viral evolution. IMPORTANCE Highly pathogenic avian influenza viruses represent a threat to poultry production systems and to human health because of their impact on food security and because of their zoonotic potential. It is therefore crucial to better understand how these viruses emerge. Using a within-host competition model between highly and low pathogenic avian influenza viruses, we provide evidence that highly pathogenic avian influenza viruses could be more likely to emerge in chickens than in ducks. These results have important implications for highly pathogenic avian influenza virus emergence prevention and they underscore the importance of within-host viral variants interactions in virus evolution.

scholarly journals Characterization of the In Vitro and In Vivo Efficacy of Baloxavir Marboxil against the H5 Highly Pathogenic Avian Influenza Virus Infection

2021 ◽  
Author(s):  
Keiichi Taniguchi ◽  
Yoshinori Ando ◽  
Masanori Kobayashi ◽  
Shinsuke Toba ◽  
Haruaki Nobori ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Avian Influenza ◽  
Avian Influenza Virus ◽  
Highly Pathogenic Avian Influenza ◽  
Influenza Virus Infection ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza ◽  
Antiviral Efficacy ◽  
Pathogenic Avian Influenza Virus

Human infections with the H5 highly pathogenic avian influenza virus (HPAIV) sporadically threatens public health. The susceptibility of HPAIVs to baloxavir acid (BXA), which is a new class of inhibitor for the influenza virus cap-dependent endonuclease, has been confirmed in vitro, but has not yet been characterized fully. Here, the efficacy of BXA against HPAIVs, including recent H5N8 variants in vitro was assessed. The antiviral efficacy of baloxavir marboxil (BXM) in H5N1 virus-infected mice was also investigated. BXA exhibited similar in vitro activities against H5N1, H5N6, and H5N8 variants tested to those of seasonal and other zoonotic strains. BXM monotherapy in mice infected with the H5N1 HPAIV clinical isolate; A/Hong Kong/483/1997 (H5N1) strain, also caused a significant reduction in viral titers in the lungs, brains, and kidneys, followed by prevention of acute lung inflammation and improvement of mortality compared with oseltamivir phosphate (OSP). Furthermore, combination treatments with BXM and OSP, using a 48-hour delayed treatment model showed a more potent effect on viral replication in organs, accompanied by improved survival compared to BXM or OSP monotherapy. From each test, no resistant virus (e.g., I38T in the PA) emerged in any BXM-treated mouse. These results therefore support the conclusion that BXM has potent antiviral efficacy against H5 HPAIV infections.

Sales and immunogenicity of commercial vaccines to H9N2 low pathogenic avian influenza virus in Korea from 2007 to 2017

Vaccine ◽  
2020 ◽  
Vol 38 (16) ◽  
pp. 3191-3195
Author(s):  
Hyun-Kyu Cho ◽  
Yong-Myung Kang ◽  
Hyun-Mi Kim ◽  
Chi-Ho Lee ◽  
Do-Young Kim ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Avian Influenza ◽  
Avian Influenza Virus ◽  
Pathogenic Avian Influenza ◽  
Pathogenic Avian Influenza Virus ◽  
Low Pathogenic Avian Influenza

An experimental model to analyse the risk of introduction of a duck-originated H5 low-pathogenic avian influenza virus in poultry through close contact and contaminative transmission

2013 ◽  
Vol 142 (9) ◽  
pp. 1836-1847 ◽  
Author(s):  
G. CLAES ◽  
S. MARCHÉ ◽  
J. DEWULF ◽  
T. VAN DEN BERG ◽  
B. LAMBRECHT
Keyword(s):  
Avian Influenza ◽  
Close Contact ◽  
Animal Experiments ◽  
Wild Birds ◽  
Influenza Viruses ◽  
Pathogenic Avian Influenza ◽  
Contaminated Drinking Water ◽  
Pathogenic Avian Influenza Virus ◽  
Efficient Route ◽  
Low Pathogenic Avian Influenza

SUMMARYAquatic wild birds are often carriers of low-pathogenic avian influenza viruses (LPAIVs). If H5 and H7 LPAIVs are transmitted to poultry and have the opportunity to circulate, a highly pathogenic AIV may arise. Contact with aquatic wild birds is one of the most important ways in which these LPAIVs can be introduced into poultry flocks. In this study, the transmissibility of a duck-originated H5 LPAIV between ducks and chickens was analysed in a series of animal experiments, using different transmission routes. Results indicate that the outcome of virus intake by chickens exposed to infectious ducks depends on the way the virus is presented. Faecally contaminated drinking water proved to be the most efficient route by which the virus can be transmitted to chickens. The results from this study also suggest that some duck-originated H5 LPAIVs may be introduced to poultry but do not have the potential to become established in poultry populations.

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