Isolation and characterization of H7N9 viruses from live poultry markets — Implication of the source of current H7N9 infection in humans

Shi, Jianzhong; Deng, Guohua; Liu, Peihong; Zhou, Jinlin; Guan, Lizheng; Li, Wenhui; Li, XuYong; Guo, Jing; Wang, Guojun; Fan, Jun; Wang, Jinliang; Li, Yuanyuan; Jiang, Yongping; Liu, Liling; Tian, Guobin; Liu, Chengjun; Chen, Hualan

doi:10.1007/s11434-013-5873-4

Cited by 149 publications

(174 citation statements)

References 27 publications

Supporting

Mentioning

166

Contrasting

Unclassified

Order By: Relevance

“…Phylogenetic analysis has revealed that the hemagglutinin (HA) and neuraminidase (NA) genes of the A(H7N9) viruses share the greatest sequence identities with Eurasian avian A(H7N3) viruses and N9 viruses of different HA subtypes, respectively (3)(4)(5)(6). The other six viral genes are highly related to A(H9N2) viruses that have circulated in poultry in China (1,(3)(4)(5)(6)(7). These findings indicate that A(H7N9) viruses are reassortant viruses with genes from several avian isolates.…”

mentioning

confidence: 99%

Virulence-Affecting Amino Acid Changes in the PA Protein of H7N9 Influenza A Viruses

Yamayoshi

Yamada

Fukuyama

et al. 2014

J Virol

108

View full text Add to dashboard Cite

Novel avian-origin influenza A(H7N9) viruses were first reported to infect humans in March 2013. To date, 143 human cases, including 45 deaths, have been recorded. By using sequence comparisons and phylogenetic and ancestral inference analyses, we identified several distinct amino acids in the A(H7N9) polymerase PA protein, some of which may be mammalian adapting. Mutant viruses possessing some of these amino acid changes, singly or in combination, were assessed for their polymerase activities and growth kinetics in mammalian and avian cells and for their virulence in mice. We identified several mutants that were slightly more virulent in mice than the wild-type A(H7N9) virus, A/Anhui/1/2013. These mutants also exhibited increased polymerase activity in human cells but not in avian cells. Our findings indicate that the PA protein of A(H7N9) viruses has several amino acid substitutions that are attenuating in mammals. (1). To date, 143 confirmed cases of A(H7N9) virus infection and 45 associated deaths have been reported. This represents a case-fatality rate of ca. 31.5%; however, this rate may actually be lower because the number of mild cases is unknown (2). Phylogenetic analysis has revealed that the hemagglutinin (HA) and neuraminidase (NA) genes of the A(H7N9) viruses share the greatest sequence identities with Eurasian avian A(H7N3) viruses and N9 viruses of different HA subtypes, respectively (3-6). The other six viral genes are highly related to A(H9N2) viruses that have circulated in poultry in China (1, 3-7). These findings indicate that A(H7N9) viruses are reassortant viruses with genes from several avian isolates. IMPORTANCE Novel avian-origin influenzaWe (8) and others (9-14) recently reported that prototype A(H7N9) viruses replicate efficiently in mammalian cells, mice, and ferrets, and transmit among subsets of pairs of ferrets. A(H7N9) viruses isolated from humans possess several amino acid changes already known to facilitate infection of mammals, including leucine at position 226 of HA (H3 HA numbering), which confers increased binding to human-type receptors (15), and lysine at position 627 (PB2-627K) (16,17) and asparagine at position 701 (PB2-701N) (18,19) in the polymerase protein PB2, which increase the polymerase activity in mammalian cells. Notably, the PB2-627K and PB2-701N markers have been detected in almost all human, but not avian or environmental, A(H7N9) isolates (6).In addition to the known mammalian-adapting amino acid changes in the PB2 and HA proteins, additional amino acid changes in A(H7N9) proteins may have enabled these viruses to infect mammals. We therefore undertook a comprehensive analysis of A(H7N9) sequences and identified several amino acids in the polymerase PA protein that are typically found in human (but not avian) influenza A viruses or are characteristic of A(H7N9) viruses (i.e., not commonly detected among human or avian influenza viruses). Here, we evaluated these distinguishing amino acid changes in vivo and in vitro. Cells. Madin-Darby canine kidney ...

show abstract

mentioning

confidence: 99%

Virulence-Affecting Amino Acid Changes in the PA Protein of H7N9 Influenza A Viruses

Yamayoshi

Yamada

Fukuyama

et al. 2014

J Virol

108

View full text Add to dashboard Cite

show abstract

“…The transmission of the China/ 2013 virus to humans probably occurred at live-bird markets and resulted in a high case fatality rate (2)(3)(4). Genetic analysis indicates that the virus represents a multiple reassortant with all of the gene segments being of complex avian ancestry.…”

mentioning

confidence: 99%

“…The hemagglutinin (HA) and neuraminidase (NA) genome segments probably descended from viruses of ducks and migratory birds, respectively, whereas the six "internal genes" might have originated from H9N2 viruses circulating in chickens in eastern China (1,5,6). The HA cleavage site of China/2013 contains a monobasic motif, indicating a low-pathogenicity phenotype in gallinaceous poultry (1,2,(4)(5)(6). Moreover, sequence analysis revealed several genetic features probably associated with its ability to replicate in mammals, like alterations in the receptor binding site (H5 numbering: G195V, Q235L/I) and loss of a glycosylation site (T169A) within the HA protein, as well as either the E627K or the D701N substitution in PB2 of H7N9 China/2013 viruses isolated from humans (1,(5)(6)(7)(8)(9).…”

mentioning

confidence: 99%

“…To this end, we infected chickens and pigeons; both species are involved as avian hosts in the current circulation of the H7N9 virus in China (4,8). The ferret is considered a suitable mammalian model in which to study the pathogenicity (and transmissibility) of influenza viruses of various origins (22,23) and was included here to comparatively investigate the pathogenicity to mammals of the novel avian H7N9 virus and a "standard" LP H7N7 virus.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Avian Influenza H7N9/13 and H7N7/13: a Comparative Virulence Study in Chickens, Pigeons, and Ferrets

Kalthoff

Bogs

Grund

et al. 2014

J Virol

View full text Add to dashboard Cite

Human influenza cases caused by a novel avian H7N9 virus in China emphasize the zoonotic potential of that subtype. We compared the infectivity and pathogenicity of the novel H7N9 virus with those of a recent European avian H7N7 strain in chickens, pigeons, and ferrets. Neither virus induced signs of disease despite substantial replication in inoculated chickens and rapid transmission to contact chickens. Evidence of the replication of both viruses in pigeons, albeit at lower levels of RNA excretion, was also detected. No clear-cut differences between the two H7 isolates emerged regarding replication and antibody development in avian hosts. In ferrets, in contrast, greater replication of the avian H7N9 virus than of the H7N7 strain was observed with significant differences in viral presence, e.g., in nasal wash, lung, and cerebellum samples. Importantly, both viruses showed the potential to spread to the mammal brain. We conclude that efficient asymptomatic viral replication and shedding, as shown in chickens, facilitate the spread of H7 viruses that may harbor zoonotic potential. Biosafety measures are required for the handling of poultry infected with avian influenza viruses of the H7 subtype, independently of their pathogenicity for gallinaceous poultry. IMPORTANCEThis study is important to the field since it provides data about the behavior of the novel H7N9 avian influenza virus in chickens, pigeons, and ferrets in comparison with that of a recent low-pathogenicity H7N7 strain isolated from poultry. We clearly show that chickens, but not pigeons, are highly permissive hosts of both H7 viruses, allowing high-titer replication and virus shedding without any relevant clinical signs. In the ferret model, the potential of both viruses to infect mammals could be demonstrated, including infection of the brain. However, the replication efficiency of the H7N9 virus in ferrets was higher than that of the H7N7 strain. In conclusion, valuable data for the risk analysis of low-pathogenicity avian influenza viruses of the H7 subtype are provided that could also be used for the risk assessment of zoonotic potentials and necessary biosafety measures.

show abstract

“…Most recently, another animal influenza virus, this time of purely avian origin, was introduced into the human population in the east of China: influenza A subtype H7N9 [2], hereafter referred to as avian H7N9 virus. At least 354 people were infected, most probably after contact with infected poultry, other avian species, or contaminated environment [3,4]. A total of 113 deaths ensued (last revised on 18 February 2014, WHO) [5].…”

Section: Introductionmentioning

confidence: 99%

Nucleic acid-based detection of influenza A virus subtypes H7 and N9 with a special emphasis on the avian H7N9 virus

et al. 2014

View full text Add to dashboard Cite

In 2013, a novel influenza A virus of subtype H7N9 was transmitted from avian sources to humans in China, causing severe illness and substantial mortality. Rapid and sensitive diagnostic approaches are the basis of epidemiological studies and of utmost importance for the detection of infected humans and animals. We developed various quantitative reverse transcriptase PCR (RT-qPCR) assays for (i) the generic detection of the haemagglutinin (HA) gene of H7 viruses or the neuraminidase (NA) gene of N9 viruses, and (ii) the specific detection of HA and NA of the novel avian H7N9/2013 virus. The sensitivity of the newly developed assays was compared with previously published PCRs, and the specificity of all RT-qPCRs was examined using a panel of 42 different H7 and 16 different N9 isolates. Furthermore, we analysed the performance of the RT-qPCR assays with dilution series and diagnostic samples obtained from animal experiments. Our study provides a comprehensive set of RT-qPCR assays for the reliable detection of the novel avian H7N9 virus, with high sensitivity and improved and tailored specificity values compared with published assays. Finally, we also present data about the robustness of a duplex assay for the simultaneous detection of HA and NA of the avian influenza H7N9/2013 virus.

show abstract

Isolation and characterization of H7N9 viruses from live poultry markets — Implication of the source of current H7N9 infection in humans

Cited by 149 publications

References 27 publications

Virulence-Affecting Amino Acid Changes in the PA Protein of H7N9 Influenza A Viruses

Virulence-Affecting Amino Acid Changes in the PA Protein of H7N9 Influenza A Viruses

Avian Influenza H7N9/13 and H7N7/13: a Comparative Virulence Study in Chickens, Pigeons, and Ferrets

Nucleic acid-based detection of influenza A virus subtypes H7 and N9 with a special emphasis on the avian H7N9 virus

Contact Info

Product

Resources

About