scholarly journals SequenceAnalysis of Recent H7 Avian Influenza Viruses Associated with ThreeDifferent Outbreaks in Commercial Poultry in the UnitedStates

2003 ◽  
Vol 77 (24) ◽  
pp. 13399-13402 ◽  
Author(s):  
Erica Spackman ◽  
Dennis A. Senne ◽  
Sherrill Davison ◽  
David L. Suarez
Keyword(s):  
Amino Acids ◽  
Avian Influenza ◽  
Cleavage Site ◽  
Influenza Viruses ◽  
Avian Influenza Viruses ◽  
Receptor Binding Site ◽  
Highly Pathogenic ◽  
Genetic Features ◽  
Commercial Poultry ◽  
Live Bird

ABSTRACT The hemagglutinin (HA) and neuraminidase (NA) genes of H7 avian influenza virus (AIV) isolated between 1994 and 2002 from live-bird markets (LBMs) in the northeastern United States and from three outbreaks in commercial poultry have been characterized. Phylogenetic analysis of the HA and NA genes demonstrates that the isolates from commercial poultry were closely related to the viruses circulating in the LBMs. Also, since 1994, two distinguishing genetic features have appeared in this AIV lineage: a deletion of 17 amino acids in the NA protein stalk region and a deletion of 8 amino acids in the HA1 protein which is putatively in part of the receptor binding site. Furthermore, analysis of the HA cleavage site amino acid sequence, a marker for pathogenicity in chickens and turkeys, shows a progression toward a cleavage site sequence that fulfills the molecular criteria for highly pathogenic AIV.

scholarly journals Molecular Determinants within the Surface Proteins Involved in the Pathogenicity of H5N1 Influenza Viruses in Chickens

2004 ◽  
Vol 78 (18) ◽  
pp. 9954-9964 ◽  
Author(s):  
Diane J. Hulse ◽  
Robert G. Webster ◽  
Rupert J. Russell ◽  
Daniel R. Perez
Keyword(s):  
Amino Acids ◽  
Avian Influenza ◽  
Cleavage Site ◽  
Glycosylation Site ◽  
Influenza Viruses ◽  
Surface Proteins ◽  
Avian Influenza Viruses ◽  
Highly Pathogenic ◽  
H5n1 Influenza ◽  
High Pathogenicity

ABSTRACT Although it is established that the cleavage site and glycosylation patterns in the hemagglutinin (HA) play important roles in determining the pathogenicity of H5 avian influenza viruses, some viruses exist that are not highly pathogenic despite possessing the known characteristics of high pathogenicity (i.e., their HA contains multiple basic amino acids at the cleavage site and has glycosylation patterns similar to that of the highly pathogenic H5 viruses). Currently little is known about the H5N1 viruses that fall into this intermediate category of pathogenicity. We have identified strains of H5N1 avian influenza viruses that have markers typical of high pathogenicity but distinctly differ in their ability to cause disease and death in chickens. By analyzing viruses constructed by reverse-genetic methods and containing recombinant HAs, we established that amino acids 97, 108, 126, 138, 212, and 217 of HA, in addition to those within the cleavage site, affect pathogenicity. Further investigation revealed that an additional glycosylation site within the neuraminidase (NA) protein globular head contributed to the high virulence of the H5N1 virus. Our findings are in agreement with previous observations that suggest that the activities of the HA and NA proteins are functionally linked.

scholarly journals Insertion of Basic Amino Acids in the Hemagglutinin Cleavage Site of H4N2 Avian Influenza Virus (AIV)—Reduced Virus Fitness in Chickens is Restored by Reassortment with Highly Pathogenic H5N1 AIV

2020 ◽  
Vol 21 (7) ◽  
pp. 2353
Author(s):  
Marcel Gischke ◽  
Reiner Ulrich ◽  
Olanrewaju I. Fatola ◽  
David Scheibner ◽  
Ahmed H. Salaheldin ◽  
...  
Keyword(s):  
Amino Acids ◽  
Avian Influenza ◽  
Cleavage Site ◽  
Influenza Viruses ◽  
Viral Fitness ◽  
Highly Pathogenic ◽  
Basic Amino Acids ◽  
The Impact ◽  
Virus Fitness

Highly pathogenic (HP) avian influenza viruses (AIVs) are naturally restricted to H5 and H7 subtypes with a polybasic cleavage site (CS) in hemagglutinin (HA) and any AIV with an intravenous pathogenicity index (IVPI) ≥ 1.2. Although only a few non-H5/H7 viruses fulfill the criteria of HPAIV; it remains unclear why these viruses did not spread in domestic birds. In 2012, a unique H4N2 virus with a polybasic CS 322PEKRRTR/G329 was isolated from quails in California which, however, was avirulent in chickens. This is the only known non-H5/H7 virus with four basic amino acids in the HACS. Here, we investigated the virulence of this virus in chickens after expansion of the polybasic CS by substitution of T327R (322PEKRRRR/G329) or T327K (322PEKRRKR/G329) with or without reassortment with HPAIV H5N1 and H7N7. The impact of single mutations or reassortment on virus fitness in vitro and in vivo was studied. Efficient cell culture replication of T327R/K carrying H4N2 viruses increased by treatment with trypsin, particularly in MDCK cells, and reassortment with HPAIV H5N1. Replication, virus excretion and bird-to-bird transmission of H4N2 was remarkably compromised by the CS mutations, but restored after reassortment with HPAIV H5N1, although not with HPAIV H7N7. Viruses carrying the H4-HA with or without R327 or K327 mutations and the other seven gene segments from HPAIV H5N1 exhibited high virulence and efficient transmission in chickens. Together, increasing the number of basic amino acids in the H4N2 HACS was detrimental for viral fitness particularly in vivo but compensated by reassortment with HPAIV H5N1. This may explain the absence of non-H5/H7 HPAIV in poultry.

scholarly journals Alterations in Hemagglutinin Receptor-Binding Specificity Accompany the Emergence of Highly Pathogenic Avian Influenza Viruses

2015 ◽  
Vol 89 (10) ◽  
pp. 5395-5405 ◽  
Author(s):  
Alla Heider ◽  
Larisa Mochalova ◽  
Timm Harder ◽  
Alexander Tuzikov ◽  
Nicolai Bovin ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Receptor Binding ◽  
Cleavage Site ◽  
Highly Pathogenic Avian Influenza ◽  
Binding Specificity ◽  
Influenza Viruses ◽  
Avian Influenza Viruses ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza ◽  
Receptor Binding Specificity

ABSTRACTHighly pathogenic avian influenza viruses (HPAIVs) of hemagglutinin H5 and H7 subtypes emerge after introduction of low-pathogenic avian influenza viruses (LPAIVs) from wild birds into poultry flocks, followed by subsequent circulation and evolution. The acquisition of multiple basic amino acids at the endoproteolytical cleavage site of the hemagglutinin (HA) is a molecular indicator for high pathogenicity, at least for infections of gallinaceous poultry. Apart from the well-studied significance of the multibasic HA cleavage site, there is only limited knowledge on other alterations in the HA and neuraminidase (NA) molecules associated with changes in tropism during the emergence of HPAIVs from LPAIVs. We hypothesized that changes in tropism may require alterations of the sialyloligosaccharide specificities of HA and NA. To test this hypothesis, we compared a number of LPAIVs and HPAIVs for their HA-mediated binding and NA-mediated desialylation of a set of synthetic receptor analogs, namely, α2-3-sialylated oligosaccharides. NA substrate specificity correlated with structural groups of NAs and did not correlate with pathogenic potential of the virus. In contrast, all HPAIVs differed from LPAIVs by a higher HA receptor-binding affinity toward the trisaccharides Neu5Acα2-3Galβ1-4GlcNAcβ (3′SLN) and Neu5Acα2-3Galβ1-3GlcNAcβ (SiaLec) and by the ability to discriminate between the nonfucosylated and fucosylated sialyloligosaccharides 3′SLN and Neu5Acα2-3Galβ1-4(Fucα1-3)GlcNAcβ (SiaLex), respectively. These results suggest that alteration of the receptor-binding specificity accompanies emergence of the HPAIVs from their low-pathogenic precursors.IMPORTANCEHere, we have found for the first time correlations of receptor-binding properties of the HA with a highly pathogenic phenotype of poultry viruses. Our study suggests that enhanced receptor-binding affinity of HPAIVs for a typical “poultry-like” receptor, 3′SLN, is provided by substitutions in the receptor-binding site of HA which appeared in HA of LPAIVs in the course of transmission of LPAIVs from wild waterfowl into poultry flocks, with subsequent adaptation in poultry. The identification of LPAIVs with receptor characteristics of HPAIVs argues that the sialic acid-binding specificity of the HA may be used as a novel phenotypic marker of HPAIVs.

scholarly journals A Decade of Avian Influenza in Bangladesh: Where Are We Now?

2019 ◽  
Vol 4 (3) ◽  
pp. 119 ◽  
Author(s):  
Rimi ◽  
Hassan ◽  
Chowdhury ◽  
Rahman ◽  
Sultana ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Resource Limitation ◽  
Influenza Viruses ◽  
Avian Influenza Viruses ◽  
Short Term ◽  
Highly Pathogenic ◽  
Predominant Genotype ◽  
Key Stakeholders ◽  
The Government ◽  
Live Bird

Highly pathogenic avian influenza (HPAI) has been a public health threat in Bangladesh since the first reported outbreak in poultry in 2007. The country has undertaken numerous efforts to detect, track, and combat avian influenza viruses (AIVs). The predominant genotype of the H5N1 viruses is clade 2.3.2.1a. The persistent changing of clades of the circulating H5N1 strains suggests probable mutations that might have been occurring over time. Surveillance has provided evidence that the virus has persistently prevailed in all sectors and caused discontinuous infections. The presence of AIV in live bird markets has been detected persistently. Weak biosecurity in the poultry sector is linked with resource limitation, low risk perception, and short-term sporadic interventions. Controlling avian influenza necessitates a concerted multi-sector ‘One Health’ approach that includes the government and key stakeholders.

scholarly journals H9 avian influenza reassortant with engineered polybasic cleavage site displays a highly pathogenic phenotype in chicken

2011 ◽  
Vol 92 (8) ◽  
pp. 1843-1853 ◽  
Author(s):  
Sandra Gohrbandt ◽  
Jutta Veits ◽  
Angele Breithaupt ◽  
Jana Hundt ◽  
Jens P. Teifke ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Cleavage Site ◽  
Influenza Viruses ◽  
The Other ◽  
Virulence Determinants ◽  
Avian Influenza Viruses ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza ◽  
Ha Gene ◽  
Virulence Potential

In the field, highly pathogenic avian influenza viruses (HPAIV) originate from low-pathogenic strains of the haemagglutinin (HA) serotypes H5 and H7 that have acquired a polybasic HA cleavage site. This observation suggests the presence of a cryptic virulence potential of H5 and H7 low-pathogenic avian influenza viruses (LPAIV). Among all other LPAIV, the H9N2 strains are of particular relevance as they have become widespread across many countries in several avian species and have been transmitted to humans. To assess the potential of these strains to transform into an HPAIV, we introduced a polybasic cleavage site into the HA of a contemporary H9N2 isolate. Whereas the engineered polybasic HA cleavage site mutant remained a low-pathogenic strain like its parent virus, a reassortant expressing the modified H9 HA with engineered polybasic cleavage site and all the other genes from an H5N1 HPAIV became highly pathogenic in chicken with an intravenous pathogenicity index of 1.23. These results suggest that an HPAIV with a subtype other than H5 or H7 would only emerge under conditions where the HA gene could acquire a polybasic cleavage site and the other viral genes carry additional virulence determinants.

scholarly journals Amino acids adjacent to the haemagglutinin cleavage site are relevant for virulence of avian influenza viruses of subtype H5

2010 ◽  
Vol 92 (1) ◽  
pp. 51-59 ◽  
Author(s):  
S. Gohrbandt ◽  
J. Veits ◽  
J. Hundt ◽  
J. Bogs ◽  
A. Breithaupt ◽  
...  
Keyword(s):  
Amino Acids ◽  
Avian Influenza ◽  
Cleavage Site ◽  
Influenza Viruses ◽  
Avian Influenza Viruses

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.

Sign in / Sign up

Export Citation Format

Share Document