scholarly journals A Semiquantitative Scoring System for Histopathological and Immunohistochemical Assessment of Lesions and Tissue Tropism in Avian Influenza

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 868
Author(s):  
Maria Landmann ◽  
David Scheibner ◽  
Annika Graaf ◽  
Marcel Gischke ◽  
Susanne Koethe ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Scoring System ◽  
Viral Antigen ◽  
Meta Analysis ◽  
Influenza Viruses ◽  
Tissue Tropism ◽  
Multiple Organs ◽  
Viral Subtype ◽  
Marked Variability ◽  
Wide Range

The main findings of the post-mortem examination of poultry infected with highly pathogenic avian influenza viruses (HPAIV) include necrotizing inflammation and viral antigen in multiple organs. The lesion profile displays marked variability, depending on viral subtype, strain, and host species. Therefore, in this study, a semiquantitative scoring system was developed to compare histopathological findings across a wide range of study conditions. Briefly, the severity of necrotizing lesions in brain, heart, lung, liver, kidney, pancreas, and/or lymphocytic depletion in the spleen is scored on an ordinal four-step scale (0 = unchanged, 1 = mild, 2 = moderate, 3 = severe), and the distribution of the viral antigen in parenchymal and endothelial cells is evaluated on a four-step scale (0 = none, 1 = focal, 2 = multifocal, 3 = diffuse). These scores are used for a meta-analysis of experimental infections with H7N7 and H5N8 (clade 2.3.4.4b) HPAIV in chickens, turkeys, and ducks. The meta-analysis highlights the rather unique endotheliotropism of these HPAIV in chickens and a more severe necrotizing encephalitis in H7N7-HPAIV-infected turkeys. In conclusion, the proposed scoring system can be used to condensate HPAIV-typical pathohistological findings into semiquantitative data, thus enabling systematic phenotyping of virus strains and their tissue tropism.

scholarly journals Highly Pathogenic Avian Influenza (H5N1) Virus in Feathers

2016 ◽  
Vol 54 (2) ◽  
pp. 226-233 ◽  
Author(s):  
H. Nuradji ◽  
J. Bingham ◽  
J. Payne ◽  
J. Harper ◽  
S. Lowther ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Viral Antigen ◽  
Highly Pathogenic Avian Influenza ◽  
Apparent Difference ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza ◽  
Multiple Organs ◽  
Diagnostic Detection ◽  
Influenza H5n1 ◽  
H5n1 Hpai

H5N1 highly pathogenic avian influenza (HPAI) virus causes high mortality of infected birds, with infection in multiple organs, including in feathers. Feathers have been proposed as samples for diagnosis of HPAI infection in birds, and this study is part of a broader investigation validating the use of feathers for diagnostic purposes. To understand and characterize the morphological basis for feather infection, sections from 7 different skin tracts of ducks and chickens infected with 3 different clades of H5N1 HPAI virus from Indonesia and Vietnam were examined histologically. Results showed that in ducks, lesions and viral antigen were mainly detected in the epidermis of feathers and follicles, whereas in chickens, they were mostly found in the dermis of these structures. Abundant viral antigen was found in nearly all the feathers examined from chickens, and there was no apparent difference between virus isolates or skin tracts in the proportion of feathers that were antigen positive. By immunohistochemistry, the majority of feathers from most skin tracts from ducks infected with a Vietnamese H5N1 HPAI virus contained abundant levels of viral antigen, while few feathers were antigen positive from ducks infected with 2 Indonesian viruses. These results support and inform the use of feathers for diagnostic detection of H5N1 HPAI virus in birds.

Novel means of viral antigen identification: Improved detection of avian influenza viruses by proximity ligation

2010 ◽  
Vol 163 (1) ◽  
pp. 116-122 ◽  
Author(s):  
Joerg Schlingemann ◽  
Mikael Leijon ◽  
Alia Yacoub ◽  
Heidi Schlingemann ◽  
Siamak Zohari ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Viral Antigen ◽  
Influenza Viruses ◽  
Avian Influenza Viruses ◽  
Proximity Ligation

scholarly journals A Systematic Review and Meta-Analysis of Practices Exposing Humans to Avian Influenza Viruses, Their Prevalence, and Rationale

2017 ◽  
Vol 97 (2) ◽  
pp. 376-388 ◽  
Author(s):  
Guillaume Fournié ◽  
Erling Høg ◽  
Tony Barnett ◽  
Dirk U. Pfeiffer ◽  
Punam Mangtani
Keyword(s):  
Systematic Review ◽  
Avian Influenza ◽  
Meta Analysis ◽  
Influenza Viruses ◽  
Avian Influenza Viruses

scholarly journals Tropism of SARS-CoV-2, SARS-CoV and influenza virus in canine tissue explants

2021 ◽  
Author(s):  
Christine H T Bui ◽  
H W Yeung ◽  
John C W Ho ◽  
Connie Y H Leung ◽  
Kenrie P Y Hui ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Avian Influenza ◽  
Influenza A ◽  
Ex Vivo ◽  
Influenza Viruses ◽  
Influenza B ◽  
Influenza A Viruses ◽  
Avian Influenza Viruses ◽  
Canine Influenza Virus ◽  
Wide Range

Abstract Background Human spillovers of SARS-CoV-2 to dogs and the emergence of a highly contagious avian-origin H3N2 canine influenza virus have raised concerns towards the role of dogs in the spread of SARS-CoV-2 and their susceptibility to existing human and avian influenza viruses which might result in further reassortment. Methods We systematically studied the replication kinetics of SARS-CoV-2, SARS-CoV, influenza A viruses of H1, H3, H5, H7 and H9 subtypes and influenza B viruses of Yamagata-like and Victoria-like lineages in ex-vivo canine nasal cavity (NC), soft palate (SP), trachea (T) and lung (L) tissue explant cultures and examined ACE2 and sialic acid (SA) receptor distribution in these tissues. Results There was limited productive replication of SARS-CoV-2 in canine NC and SARS-CoV in canine NC, SP and L with unexpectedly high ACE2 levels in canine NC and SP. Meanwhile, the canine tissues were susceptible to a wide range of human and avian influenza viruses, which matched with the abundance of both human and avian SA receptors. Conclusions Existence of suitable receptors and tropism for the same tissue foster virus adaptation and reassortment. Continuous surveillance in dog populations should be conducted given the plenty of chances for spillover during outbreaks.

scholarly journals Prevalence of Avian Influenza H5N6 in Birds: A Systematic Review and Meta-analysis of Other Viral Zoonosis

2021 ◽  
Vol 11 (2) ◽  
pp. 146-156
Author(s):  
D. Katterine Bonilla-Aldana ◽  
Yeimer Holguin-Rivera ◽  
Isabella Cortes-Bonilla ◽  
María C. Cardona-Trujillo ◽  
Alejandra García-Barco ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Meta Analysis ◽  
Wild Birds ◽  
Influenza Viruses ◽  
Considerable Proportion ◽  
Rt Pcr ◽  
Pooled Prevalence ◽  
Quantitative Analyses ◽  
Near Future ◽  
Pool Prevalence

Avian influenza viruses (AIV) are zoonotic pathogens that can potentially affect humans and potentially be epidemic in a region. Birds (such as poultry and wild birds) serve as potential reservoirs for these viruses, highlighting the importance of determining AIV prevalence in the avian population. No systematic reviews have been published on this issue in the world so far. The present systematic literature review following the PRISMA standard, with meta-analysis, used three databases to globally assess the Influenza H5N6 infection in birds (including poultry and wild birds). A model of random-effects meta-analysis was performed to calculate the pooled prevalence and 95% Confidence Interval (95% CI) for the prevalence of Influenza H5N6 infection in birds. A total number of 14,605 articles published from 2015 to 2020 were retrieved. After screening the abstract/title, 37 articles were selected for full-text assessment, and 15 were included for qualitative and quantitative analyses. Of the total number of birds (n = 13,416 birds), the pool prevalence by RT-PCR was 3.5% (95% CI: 2.8-4.3%). From the total, 39.67% of the birds assessed were ducks (family Anatidae), in which pool prevalence was 7.7% (95% CI: 4.4-11.0). In chickens (Gallus gallus domesticus), the pool prevalence was 3.3% (95% CI 1.9-4.8). Vietnam was the country with the highest pool prevalence; 7.9% (95% CI 4.0-11.7%). Bangladesh was the country with the lowest pool prevalence of 0.4% (95% CI 0.2-0.7%). A considerable proportion of infected birds tested positive highlighted the relevance of individual animals as reservoirs of H5N6. Ducks and chickens were found to be positive by RT-PCR in over 3% of the cases. These data suggest their relevance in maintaining zoonotic transmission and their potential implications for epidemics and even pandemics in the near future.

scholarly journals Review analysis and impact of co-circulating H5N1 and H9N2 avian influenza viruses in Bangladesh

2018 ◽  
Vol 146 (10) ◽  
pp. 1259-1266 ◽  
Author(s):  
Rokshana Parvin ◽  
Jahan Ara Begum ◽  
Mohammed Nooruzzaman ◽  
Emdadul Haque Chowdhury ◽  
Mohammad Rafiqul Islam ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Full Range ◽  
Influenza Viruses ◽  
Avian Influenza Viruses ◽  
Highly Pathogenic ◽  
Additional Tool ◽  
Ha Gene ◽  
Glycosylation Sites ◽  
Wide Range ◽  
Live Bird

AbstractAlmost the full range of 16 haemagglutinin (HA) and nine neuraminidase subtypes of avian influenza viruses (AIVs) has been detected either in waterfowl, land-based poultry or in the environment in Bangladesh. AIV infections in Bangladesh affected a wide range of host species of terrestrial poultry. The highly pathogenic avian influenza (AI) H5N1 and low pathogenic AI H9N2 were found to co-circulate and be well entrenched in the poultry population, which has caused serious damage to the poultry industry since 2007. By reviewing the available scientific literature, the overall situation of AIVs in Bangladesh is discussed. All Bangladeshi (BD) H5N1 and H9N2 AIV sequences available at GenBank were downloaded along with other representative sequences to analyse the genetic diversity among the circulating AIVs in Bangladesh and to compare with the global situation. Three different H5N1 clades, 2.2.2, 2.3.2.1 and 2.3.4.2, have been detected in Bangladesh. Only 2.3.2.1a is still present. The BD LP H9N2 viruses mostly belonged to the H9 G1 lineage but segregated into many branches, and some of these shared internal genes with HP viruses of subtypes H7N3 and H5N1. However, these reassortment events might have taken place before introduction to Bangladesh. Currently, H9N2 viruses continue to evolve their HA cleavage, receptor binding and glycosylation sites. Multiple mutations in the HA gene associated with adaptation to mammalian hosts were also observed. Strict biosecurity at farms and gradual phasing out of live-bird markets could be the key measures to better control AIVs, whereas stamping out is not a practicable option in Bangladesh. Vaccination also could be an additional tool, which however, requires careful planning. Continuous monitoring of AIVs through systematic surveillance and genetic characterisation of the viruses remains a hallmark of AI control.

scholarly journals Development of Clade-Specific and Broadly Reactive Live Attenuated Influenza Virus Vaccines against Rapidly Evolving H5 Subtype Viruses

2017 ◽  
Vol 91 (15) ◽  
Author(s):  
Kobporn Boonnak ◽  
Yumiko Matsuoka ◽  
Weijia Wang ◽  
Amorsolo L. Suguitan ◽  
Zhongying Chen ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Protective Efficacy ◽  
Cross Reactivity ◽  
Influenza Viruses ◽  
Immune Memory ◽  
Challenge Virus ◽  
Wide Range ◽  
Ann Arbor ◽  
Clade 1 ◽  
Human Infections

ABSTRACT We have developed pandemic live attenuated influenza vaccines (pLAIVs) against clade 1 H5N1 viruses on an Ann Arbor cold-adapted (ca) backbone that induced long-term immune memory. In 2015, many human infections caused by a new clade (clade 2.2.1.1) of goose/Guangdong (gs/GD) lineage H5N1 viruses were reported in Egypt, which prompted updating of the H5N1 pLAIV. We explored two strategies to generate suitable pLAIVs. The first approach was to modify the hemagglutinin gene of a highly pathogenic wild-type (wt) clade 2.2.1.1 virus, A/Egypt/N03434/2009 (Egy/09) (H5N1), with its unmodified neuraminidase (NA) gene; this virus was designated Egy/09 ca. The second approach was to select a low-pathogenicity avian influenza H5 virus that elicited antibodies that cross-reacted with a broad range of H5 viruses, including the Egypt H5N1 viruses, and contained a novel NA subtype for humans. We selected the low-pathogenicity A/duck/Hokkaido/69/2000 (H5N3) (dk/Hok/00) virus for this purpose. Both candidate vaccines were attenuated and immunogenic in ferrets, inducing antibodies that neutralized homologous and heterologous H5 viruses with different degrees of cross-reactivity; Egy/09 ca vaccine antisera were more specific for the gs/GD lineage viruses but did not neutralize recent North American isolates (clade 2.3.4.4), whereas antisera from dk/Hok/69 ca-vaccinated ferrets cross-reacted with clade 2.3.4.4 and 2.2.1 viruses but not clade 1 or 2.1 viruses. When vaccinated ferrets were challenged with homologous and heterologous H5 viruses, challenge virus replication was reduced in the respiratory tract. Thus, the two H5 pLAIV candidates are suitable for clinical development to protect humans from infection with different clades of H5 viruses. IMPORTANCE In response to the continuing evolution of H5N1 avian influenza viruses and human infections, new candidate H5 live attenuated vaccines were developed by using two different approaches: one targeted a specific circulating strain in Egypt, and the other was based on a virus that elicits broadly cross-reactive antibodies against a wide range of H5 viruses. Both candidate vaccines were immunogenic and exhibited protective efficacy in ferrets. Our study permits a comparison of the two approaches, and the data support the further development of both vaccine viruses to optimally prepare for the further spread of clade 2.2.1 or 2.3.4.4 viruses.

scholarly journals The molecular basis of antigenic variation among A(H9N2) avian influenza viruses

2018 ◽  
Author(s):  
Thomas P. Peacock ◽  
William T. Harvey ◽  
Jean-Remy Sadeyen ◽  
Richard Reeve ◽  
Munir Iqbal
Keyword(s):  
Avian Influenza ◽  
Molecular Basis ◽  
Influenza A ◽  
Molecular Mechanisms ◽  
Antigenic Variation ◽  
Immune Escape ◽  
Meta Analysis ◽  
Influenza Viruses ◽  
Poultry Production ◽  
Epitope Structure

AbstractAvian influenza A(H9N2) viruses are an increasing threat to global poultry production and, through zoonotic infection, to human health where they are considered viruses with pandemic potential. Vaccination of poultry is a key element of disease control in endemic countries, but vaccine effectiveness is persistently challenged by the emergence of antigenic variants. Here we employed a combination of techniques to investigate the genetic basis of H9N2 antigenic variability and evaluate the role of different molecular mechanisms of immune escape. We systematically tested the influence of published H9N2 monoclonal antibody escape mutants on chicken antisera binding, determining that many have no significant effect. Substitutions introducing additional glycosylation sites were a notable exception, though these are relatively rare among circulating viruses. To identify substitutions responsible for antigenic variation in circulating viruses, we performed an integrated meta-analysis of all published H9 haemagglutinin sequences and antigenic data. We validated this statistical analysis experimentally and allocated several new residues to H9N2 antigenic sites providing molecular markers that will help explain vaccine breakdown in the field and inform vaccine selection decisions. We find evidence for the importance of alternative mechanisms of immune escape, beyond simple modulation of epitope structure, with substitutions increasing glycosylation or receptor-binding avidity exhibiting the largest impacts on chicken antisera binding. Of these, meta-analysis indicates avidity regulation to be more relevant to the evolution of circulating viruses, suggesting that a specific focus on avidity regulation is required to fully understand the molecular basis of immune escape by influenza, and potentially other viruses.

scholarly journals An Outbreak of Highly Pathogenic Avian Influenza (H7N7) in Australia and the Potential for Novel Influenza A Viruses to Emerge

2021 ◽  
Vol 9 (8) ◽  
pp. 1639
Author(s):  
Andrew T. Bisset ◽  
Gerard F. Hoyne
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Highly Pathogenic Avian Influenza ◽  
Influenza Viruses ◽  
Human Influenza ◽  
Influenza A Viruses ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza ◽  
Wide Range ◽  
Novel Influenza A

In 2020, several geographically isolated farms in Victoria, Australia, experienced an outbreak of highly pathogenic avian influenza (HPAI) virus H7N7 and low pathogenic avian influenza (LPAI) viruses H5N2 and H7N6. Effective containment and control measures ensured the eradication of these viruses but the event culminated in substantial loss of livestock and significant economic impact. The avian HPAI H7N7 virus generally does not infect humans; however, evidence shows the ocular pathway presents a favourable tissue tropism for human infection. Through antigenic drift, mutations in the H7N7 viral genome may increase virulence and pathogenicity in humans. The Victorian outbreak also detected LPAI H7N6 in emus at a commercial farm. Novel influenza A viruses can emerge by mixing different viral strains in a host susceptible to avian and human influenza strains. Studies show that emus are susceptible to infections from a wide range of influenza viral subtypes, including H5N1 and the pandemic H1N1. The emu’s internal organs and tissues express abundant cell surface sialic acid receptors that favour the attachment of avian and human influenza viruses, increasing the potential for internal genetic reassortment and the emergence of novel influenza A viruses. This review summarises the historical context of H7N7 in Australia, considers the potential for increased virulence and pathogenesis through mutations and draws attention to the emu as potentially an unrecognised viral mixing vessel.

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