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novel reassortant h7n2 originating from the h7n9 highly pathogenic avian influenza viruses in china, 2019. 201931473272
a single amino acid substitution at residue 218 of hemagglutinin improves the growth of influenza a(h7n9) candidate vaccine viruses.the potential avian influenza pandemic remains a threat to public health, as the avian-origin influenza a(h7n9) virus has caused more than 1,560 laboratory-confirmed human infections since 2013, with nearly 40% mortality. development of low-pathogenic candidate vaccine viruses (cvvs) for vaccine production is essential for pandemic preparedness. however, the suboptimal growth of cvvs in mammalian cells and chicken eggs is often a challenge. by introducing a single adaptive substitution, g218e, i ...201931270231
single immunization with newcastle disease virus-vectored h7n9 vaccine confers a complete protection against challenge with highly pathogenic avian influenza h7n9 virus.in the fifth wave of the h7n9 avian influenza epidemic, highly pathogenic avian influenza (hpai) a (h7n9) viruses have emerged and pose a great challenge to public health and the poultry industry. in addition, there are apparent genetic and antigenic variations between the classical h7n9 avian influenza virus and the newly-emerged h7n9 virus. therefore, an antigenic-match vaccine is required for the prevention and control of h7n9 avian influenza in poultry in china. in this study, a recombinant ...201931251520
chinese poultry farmers' decision-making for avian influenza prevention: a qualitative analysis.poultry farmers faced dual risk when mutant avian influenza (ai) virus showed the zoonotic characteristics. a/h5n1 and a/h7n9 were two dominant ai virus strains that have captured the attention of the public over the years for they have been reported to bring about greater loss to poultry and human, respectively. previous studies mainly used quantitative methods investigating either the means that poultry farmers adopted for protecting their poultry against a/h5n1 infection or the poultry farmer ...201931215154
human-derived a/guangdong/th005/2017 (h7n9) exhibits extremely high replication in the lungs of ferrets and is highly pathogenic in chickens.after a series of studies on the pathogenicity of several h7n9 strains from 2013 to 2018, we wanted to dynamically track the pathogenicity of a/guangdong/th005/2017 in ferrets and poultry. the pathogenicity and transmissibility of th005, especially the distribution and replication in tissues, were studied in ferrets. we also aimed to assess the level of th005 pathogenicity in chickens. the results showed that the pathogenicity of th005 was significantly increased in ferrets and chickens, especia ...201931146467
the pathogenesis of h7 highly pathogenic avian influenza viruses in lesser scaup (aythya affinis).waterfowl are the natural hosts of avian influenza virus (aiv), and through migration spread the virus worldwide. most aivs carried by wild waterfowl are low pathogenic strains; however, goose/guangdong/1996 lineage clade 2.3.4.4 h5 highly pathogenic (hp) aiv now appears to be endemic in wild birds in much of the eastern hemisphere. most research efforts studying aiv pathogenicity in waterfowl thus far have been directed toward dabbling ducks. in order to better understand the role of diving duc ...201931131581
better fit of codon usage of the polymerase and nucleoprotein genes to the chicken host for h7n9 than h9n2 aivs. 201931125636
prevalence of h7n9 subtype avian influenza viruses in poultry in china, 2013-2018.h7n9 subtype avian influenza viruses (aiv) circulating in china over recent years have had an enormous impact on public health and economy. during the period between november 2016 and april 2017, an increase in human infections caused by these viruses was reported, with rapid emergence and spread of variants in china. consequently, the government of china implemented a controversial vaccination strategy in september 2017. here, we provide evidence of the prevalence of h7n9 aivs in china based on ...201930903740
amino acid substitutions n123d and n149d in hemagglutinin molecule enhance immunigenicity of live attenuated influenza h7n9 vaccine strain in experiment.we compared three cold-adapted live attenuated influenza vaccine strains prepared by reverse genetics methods on the basis of master donor virus a/leningrad/134/17/57 and influenza h7n9 strains a/anhui/1/2013 and a/shanghai/1/2013. two strains based on a/anhui/1/2013 differed by amino acid positions 123 and 149 in ha1 (123n/149n; 123d/149d). all strains efficiently replicated in developing chicken embryos; a/shanghai/1/2013-based strain and a/anhui/1/2013-123n/149n variant were characterized by ...201930903496
an avian influenza virus a(h7n9) reassortant that recently emerged in the united states with low pathogenic phenotype does not efficiently infect swine.in 2017, outbreaks of low and highly pathogenic avian h7n9 viruses were reported in four states in the united states. in total, over 270 000 birds died or were culled, causing significant economic loss. the potential for avian-to-swine transmission of the u.s. avian h7n9 was unknown. in an experimental challenge in swine using a representative low pathogenic h7n9 (a/chicken/tennessee/17-007431-3/2017; lpai tn/17) isolated from these events, no infectious virus in the upper and minimal virus in t ...201930761746
recombinant baculovirus vaccine expressing hemagglutinin of h7n9 avian influenza virus confers full protection against lethal highly pathogenic h7n9 virus infection in chickens.the emergent highly pathogenic avian influenza a (h7n9) (hpai) virus is a major public concern in china. therefore, it is crucially important to develop an effective vaccine against this virus. in this study, we constructed a baculovirus vaccine expressing the hemagglutinin (ha) of h7n9 strain a/chicken/jiaxing/148/2014 (jx148). the recombinant baculovirus (rbac-jx148ha) generated in this study showed good growth in insect cells and good safety, and it stably expressed the ha protein. we compare ...201930671655
comparative pathogenicity and transmissibility of pandemic h1n1, avian h5n1, and human h7n9 influenza viruses in tree shrews.influenza a viruses (iavs) continuously challenge the poultry industry and human health. studies of iavs are still hampered by the availability of suitable animal models. chinese tree shrews (tupaia belangeri chinensis) are closely related to primates physiologically and genetically, which make them a potential animal model for human diseases. in this study, we comprehensively evaluated infectivity and transmissibility in chinese tree shrews by using pandemic h1n1 (a/sichuan/1/2009, pdmh1n1), av ...201931921093
genetic and biological characteristics of avian influenza virus subtype h1n8 in environments related to live poultry markets in china.since 2008, avian influenza surveillance in poultry-related environments has been conducted annually in china. samples have been collected from environments including live poultry markets, wild bird habitats, slaughterhouses, and poultry farms. multiple subtypes of avian influenza virus have been identified based on environmental surveillance, and an h1n8 virus was isolated from the drinking water of a live poultry market.201931117981
efficacy of clarithromycin against h5n1 and h7n9 avian influenza a virus infection in cynomolgus monkeys.clarithromycin (cam), a 14-membered ring macrolide, has anti-inflammatory and immunomodulatory actions and antiviral effects in seasonal influenza virus infection. we examined the prophylactic and therapeutic efficacy of cam against h5n1 highly pathogenic and h7n9 low pathogenic avian influenza virus infections in cynomolgus monkeys. cam suppressed h5n1 virus-induced severe signs of disease in the treated monkeys and inhibited virus propagation in tracheal samples and the production of inflammat ...201931421167
identification of key amino acids in the pb2 and m1 proteins of h7n9 influenza virus that affect its transmission in guinea pigs.efficient human-to-human transmission is a prerequisite for a novel influenza virus to cause an influenza pandemic; however, the genetic determinants of influenza virus transmission are still not fully understood. in this study, we compared the respiratory droplet transmissibilities of four h7n9 viruses that are genetic closely related and found that these viruses have dissimilar transmissibilities in guinea pigs: a/anhui/1/2013 (ah/1) transmitted efficiently, whereas the other three viruses did ...201931597771
diverse biological characteristics and varied virulence of h7n9 from wave 5.there was a substantial increase with infections of h7n9 avian influenza virus (aiv) in humans during wave 5 (2016-2017). to investigate whether h7n9 had become more infectious/transmissible and pathogenic overall, we characterized the receptor binding and experimentally infected ferrets with highly pathogenic (hp)- and low pathogenic (lp)-h7n9 isolates selected from wave 5, and compared their pathogenicity and transmissibility with a wave 1 isolate from 2013. studies show that a/anhui/1/2013 (l ...201930866763
hemagglutinin-specific non-neutralizing antibody is essential for protection provided by inactivated and viral-vectored h7n9 avian influenza vaccines in chickens.hemagglutination inhibition (hi) and virus neutralization antibody (nab) do not always correlate with the protection of h7 avian influenza vaccines in mammals and humans. the contribution of different classes of antibodies induced by h7n9 vaccines to protection is poorly characterized in chickens. in this study, antibody responses induced by both inactivated and viral-vectored h7n9 vaccines in chickens were dissected. chickens immunized with inactivated h7n9 vaccine showed 50% seroconversion rat ...201931998763
avian h5n1 influenza virus infection causes severe pneumonia in the northern tree shrew (tupaia belangeri).avian-origin influenza viruses like h5n1 and h7n9 often cause severe symptoms with high mortality in humans. animal models are useful for clarification of the mechanisms of pathogenicity of these infections. in this study, to expand the potential utility of the northern tree shrew (tupaia belangeri) for influenza virus infection, we assessed the pathogenicity of h5n1 and h7n9 avian influenza viruses in tupaia. infectious virus was detected continuously from nasal, oral, tracheal, and conjunctiva ...201930684692
bioaerosol sampling to detect avian influenza virus in hanoi's largest live poultry market.newly emergent and virulent strains of h7n9 avian influenza virus are rapidly spreading in china and threaten to invade vietnam. we sought to introduce aerosol sampling for avian influenza viruses in vietnam.201930184114
emergence of waterfowl-originated gene cassettes in hpai h7n9 viruses caused severe human infection in fujian, china.highly pathogenic avian influenza (hpai) a(h7n9) virus emerged and caused human infections during the 2016-2017 epidemic wave of influenza a(h7n9) viruses in china. we report a human infection with hpai h7n9 virus and six environmental isolates in fujian province, china.201931187583
generation of h7n9-specific human polyclonal antibodies from a transchromosomic goat (caprine) system.to address the unmet needs for human polyclonal antibodies both as therapeutics and diagnostic reagents, building upon our previously established transchromosomic (tc) cattle platform, we report herein the development of a tc goat system expressing human polyclonal antibodies in their sera. in the tc goat system, a human artificial chromosome (hac) comprising the entire human immunoglobulin (ig) gene repertoire in the germline configuration was introduced into the genetic makeup of the domestic ...201930675003
recombinant hemagglutinin produced from chinese hamster ovary (cho) stable cell clones and a pelc/cpg combination adjuvant for h7n9 subunit vaccine development.the novel h7n9 avian influenza a virus has caused human infections in china since 2013; some isolates from the fifth wave of infections have emerged as highly pathogenic avian influenza viruses. recombinant hemagglutinin proteins of h7n9 viruses can be rapidly and efficiently produced with low-level biocontainment facilities. in this study, recombinant h7 antigen was obtained from engineered stable clones of chinese hamster ovary (cho) cells for subsequent large-scale production. the stable cho ...201931383491
h5n8 and h7n9 packaging signals constrain ha reassortment with a seasonal h3n2 influenza a virus.influenza a virus (iav) has a segmented genome, which (i) allows for exchange of gene segments in coinfected cells, termed reassortment, and (ii) necessitates a selective packaging mechanism to ensure incorporation of a complete set of segments into virus particles. packaging signals serve as segment identifiers and enable segment-specific packaging. we have previously shown that packaging signals limit reassortment between heterologous iav strains in a segment-dependent manner. here, we evaluat ...201930760600
a novel reassortant avian h7n6 influenza virus is transmissible in guinea pigs via respiratory droplets.since 2013, h7n9 and h5n6 avian influenza viruses (aivs) have caused sporadic human infections and deaths and continued to circulate in the poultry industry. since 2014, h7n6 viruses which might be reassortants of h7n9 and h5n6 viruses, have been isolated in china. however, the biological properties of h7n6 viruses are unknown. here, we characterize the receptor binding preference, pathogenicity and transmissibility of a h7n6 virus a/chicken/hubei/00095/2017(h7n6) (abbreviated hb95), and a close ...201930723462
comparative pathogenicity and transmissibility of the h7n9 highly pathogenic avian influenza virus and the h7n9 low pathogenic avian influenza virus in chickens.there were five outbreaks of h7n9 influenza virus in humans in china since it emerged in 2013, infecting >1000 people. the h7n9 low pathogenic influenza virus was inserted into four amino acids in the ha protein cleavage site to mutate into the h7n9 highly pathogenic virus. this emerging virus caused 15 outbreaks in chickens from the end of 2016 to date. two h7n9 avian influenza virus (aiv) strains, a/chicken/guangdong/a46/2013 (lpaiv) and a/chicken/guangdong/q29/2017 (hpaiv), were selected to c ...201931717632
characterization of mouse monoclonal antibodies against the ha of a(h7n9) influenza virus.many cases of human infection with the h7n9 virus have been detected in china since 2013. h7n9 viruses are maintained in chickens and are transmitted to humans at live bird markets. during circulation in birds, h7n9 viruses have accumulated amino acid substitutions in their hemagglutinin (ha), which resulted in an antigenically change in the recent h7n9 viruses. here, we characterized 46 mouse monoclonal antibodies against the ha of the prototype strain. 16 h7-ha-specific monoclonal antibodies ( ...201930754701
pathogenicity of two novel human-origin h7n9 highly pathogenic avian influenza viruses in chickens and ducks.human infection by low-pathogenic avian influenza viruses of the h7n9 subtype was first reported in march 2013 in china. subsequently, these viruses caused five outbreaks through september 2017. in the fifth outbreak, h7n9 virus possessing a multiple basic amino acid insertion in the cleavage site of hemagglutinin emerged and caused 4% of all human infections in that period. to date, h7n9 highly pathogenic avian influenza viruses (hpaivs) have been isolated from poultry, mostly chickens, as well ...201930539262
the optimized fusion protein ha1-2-flicδd2d3 promotes mixed th1/th2 immune responses to influenza h7n9 with low induction of systemic proinflammatory cytokines in mice.h7n9 influenza virus has an unusually high fatality rate of approximately 40%, and a safe and effective vaccine against this subtype is urgently needed. flagellin, a toll-like receptor (tlr) 5 agonist, has been deemed as a potent adjuvant candidate. however, its high antigenicity and potential for causing inflammatory injury might restrict its clinical application. previously, we demonstrated that a fusion protein, ha1-2-flic, comprising the hemagglutinin globular head protein (ha1-2) of h7n9 in ...201930389471
intranasally administered protein coated chitosan nanoparticles encapsulating influenza h9n2 ha2 and m2e mrna molecules elicit protective immunity against avian influenza viruses in chickens.chitosan nanoparticles (cnps) represent an efficient vaccination tool to deliver immunogenic antigens to the antigen-presenting cells (apcs), which subsequently stimulate protective immune responses against infectious diseases. herein, we prepared cnps encapsulating mrna molecules followed by surface coating with conserved h9n2 ha2 and m2e influenza proteins. we demonstrated that cnps efficiently delivered mrna molecules into apcs and had effectively penetrated the mucosal barrier to reach to th ...202032143695
characterization of h7n9 avian influenza viruses isolated from duck meat products.avian influenza h7n9 viruses have caused five epidemic waves of human infections since the first human cases were reported in 2013. in 2016, the initial low pathogenic avian influenza (lpai) h7n9 viruses became highly pathogenic, acquiring multi-basic amino acids at the haemagglutinin cleavage site. these highly pathogenic avian influenza (hpai) h7n9 viruses have been detected in poultry and humans in china, causing concerns of a serious threat to global public health. in japan, both hpai and lp ...202031650680
genetic and antigenic characterization of h5 and h7 avian influenza viruses isolated from migratory waterfowl in mongolia from 2017 to 2019.the circulation of highly pathogenic avian influenza viruses (hpaivs) of various subtypes (e.g., h5n1, h5n6, h5n8, and h7n9) in poultry remains a global concern for animal and public health. migratory waterfowls play important roles in the transmission of these viruses across countries. to monitor virus spread by wild birds, active surveillance for avian influenza in migratory waterfowl was conducted in mongolia from 2015 to 2019. in total, 5000 fecal samples were collected from lakesides in cen ...202032430568
development of high-growth influenza h7n9 prepandemic candidate vaccine viruses in suspension mdck cells.influenza vaccine manufacturers traditionally use egg-derived candidate vaccine viruses (cvvs) to produce high-yield influenza viruses for seasonal or pandemic vaccines; however, these egg-derived cvvs need an adaptation process for the virus to grow in mammalian cells. the low yields of cell-based manufacturing systems using egg-derived cvvs remain an unsolved issue. this study aimed to develop high-growth cell-derived cvvs for mdck cell-based vaccine manufacturing platforms.202032241276
genetic and antigenic characterization of the first h7n7 low pathogenic avian influenza viruses isolated in vietnam.during the annual surveillance of avian influenza viruses (aivs) in vietnam in 2018, three h7n7 aiv isolates were identified in domestic ducks in a single flock in vinh long province. the present study is the first documented report of h7n7 virus isolates in vietnam and aimed to characterize these viruses, both genetically and antigenically. deduced amino acid sequences for the hemagglutinins (has) indicated a low pathogenicity of these viruses in chickens. phylogenetic analysis revealed that th ...202031760087
human matriptase/st 14 proteolytically cleaves h7n9 hemagglutinin and facilitates the activation of influenza a/shanghai/2/2013 virus in cell culture.influenza is a zoonotic disease that infects millions of people each year resulting in hundreds of thousands of deaths, and in turn devastating pandemics. influenza is caused by influenza viruses, including influenza a virus (iav). there are many subtypes of iav but only a few seem to be able to adapt to humans and to cause disease. in 2013, an h7n9 iav subtype emerged in china that does not cause clinical symptoms in its chicken host but leads to severe infections when transmitted into humans. ...202031820577
mouse adaptation of the h9n2 avian influenza virus causes the downregulation of genes related to innate immune responses and ubiquitin-mediated proteolysis in mice.h9n2 avian influenza viruses sporadically infect humans worldwide. these viruses have also contributed internal genes to h5n1, h5n6, h7n9, and h10n8 viruses, which have been isolated from humans with infections and are a substantial public health threat. to investigate the potential pathogenic mechanism of the h9n2 virus, we performed serial lung-to-lung passage of an avirulent h9n2 avian influenza virus (a/chicken/shandong/416/2016 [sd/416]) in mice to increase the pathogenicity of this virus. ...202031982962
geographical variation in the risk of h7n9 human infections in china: implications for risk-based surveillance.the influenza a (h7n9) subtype remains a public health problem in china affecting individuals in contact with live poultry, particularly at live bird markets. despite enhanced surveillance and biosecurity at lbms h7n9 viruses are now more widespread in china. this study aims to quantify the temporal relationship between poultry surveillance results and the onset of human h7n9 infections during 2013-2017 and to estimate risk factors associated with geographical risk of h7n9 human infections in co ...202032587266
l226q mutation on influenza h7n9 virus hemagglutinin increases receptor-binding avidity and leads to biased antigenicity evaluation.since the first outbreak in 2013, the influenza a (h7n9) virus has continued emerging and has caused over five epidemic waves. suspected antigenic changes of the h7n9 virus based on hemagglutination inhibition (hi) assay during the fifth outbreak have prompted the update of h7n9 candidate vaccine viruses (cvvs). in this study, we comprehensively compared the serological cross-reactivities induced by the hemagglutinins (has) of the earlier cvv a/anhui/1/2013 (h7/ah13) and the updated a/guangdong/ ...202032796071
evaluation of the immune response of a h7n9 candidate vaccine virus derived from the fifth wave a/guangdong/17sf003/2016.highly pathogenic influenza h7n9 viruses that emerged in the fifth wave of h7n9 outbreak pose a risk to human health. the world health organization has updated the candidate vaccine viruses for h7n9 viruses recently. in this study, we evaluated the immune response to an updated h7n9 candidate vaccine virus, which derived from the highly pathogenic a/guangdong/17sf003/2016 (gd/16) in mice and rhesus macaques. gd/16 vaccination elicited robust neutralizing, virus-specific immunoglobulin g antibodi ...202032201204
low replicative fitness of neuraminidase inhibitor-resistant h7n9 avian influenza a virus with r292k substitution in neuraminidase in cynomolgus macaques compared with i222t substitution.human cases of h7n9 influenza a virus infection have been increasing since 2013. the first choice of treatment for influenza is neuraminidase (na) inhibitors (nais), but there is a concern that nai-resistant viruses are selected in the presence of nais. in our previous study, an h7n9 virus carrying aa substitution of threonine (t) for isoleucine (i) at residue 222 in na (na222t, n2 numbering) and an h7n9 virus carrying aa substitution of lysine (k) for arginine (r) at residue 292 in na (na292k, ...202032272175
an r195k mutation in the pa-x protein increases the virulence and transmission of influenza a virus in mammalian hosts.in the 21st century, the emergence of h7n9 and h1n1/2009 influenza viruses, originating from animals and causing severe human infections, has prompted investigations into the genetic alterations required for cross-species transmission. we previously found that replacement of the human-origin pa gene segment in avian influenza virus (aiv) could overcome barriers to cross-species transmission. recently, it was reported that the pa gene segment encodes both the pa protein and a second protein, pa-x ...202032161172
analysis of the codon usage pattern of ha and na genes of h7n9 influenza a virus.novel h7n9 influenza virus transmitted from birds to human and, since march 2013, it has caused five epidemic waves in china. although the evolution of h7n9 viruses has been investigated, the evolutionary changes associated with codon usage are still unclear. herein, the codon usage pattern of two surface glycoproteins, hemagglutinin (ha) and neuraminidase (na), was studied to understand the evolutionary changes in relation to host, epidemic wave, and pathogenicity. both genes displayed a low co ...202032992529
immune escape adaptive mutations in the h7n9 avian influenza hemagglutinin protein increase virus replication fitness and decrease pandemic potential.h7n9 avian influenza viruses (aivs) continue to evolve and remain a huge threat to human health and the poultry industry. previously, serially passaging the h7n9 a/anhui/1/2013 virus in the presence of homologous ferret antiserum resulted in immune escape viruses containing amino acid substitutions alanine to threonine at residues 125 (a125t) and 151 (a151t) and leucine to glutamine at residue 217 (l217q) in the hemagglutinin (ha) protein. these ha mutations have also been found in field isolate ...202032699084
induction of cross-group broadly reactive antibody response by natural h7n9 avian influenza virus infection and immunization with inactivated h7n9 vaccine in chickens.pre-existing immunity against the conserved haemagglutinin (ha) stalk underlies the elicitation of cross-group antibody induced by natural h7n9 virus infection and immunization in humans. however, whether broadly reactive antibodies can be induced by h7n9 infection and immunization in the absence of pre-existing stalk-specific immunity is unclear. in this study, antibody response induced by h7n9 virus infection and immunization with inactivated and viral-vectored h7n9 vaccines in naïve chickens ...202032602258
h7n9 influenza virus in china.in early 2013, human infections caused by a novel h7n9 avian influenza virus (aiv) were first reported in china; these infections caused severe disease and death. the virus was initially low pathogenic to poultry, enabling it to spread widely in different provinces, especially in live poultry markets. importantly, the h7n9 low pathogenic aivs (lpaivs) evolved into highly pathogenic aivs (hpaivs) in the beginning of 2017, causing a greater threat to human health and devastating losses to the poul ...202032205415
reassortment and adaptive mutations of an emerging avian influenza virus h7n4 subtype in china.human infections with avian influenza viruses including h5, h7 and h9 hemagglutinin subtypes occur at a low rate. among human infections with h7 viruses, regional outbreaks with h7n2, h7n3, h7n7 and h7n9 have been documented. early in 2018, a human infection with a novel h7n4 avian influenza virus was reported in jiangsu, china. this study is aimed at understanding the probable origin and molecular features of this emerging h7n4 virus. genomic segments encoding hemagglutinin (ha) and neuraminida ...202031951605
amino acid mutations a286v and t437m in the nucleoprotein attenuate h7n9 viruses in mice.the low-pathogenic h7n9 influenza viruses that emerged in 2013 acquired an insertion of four amino acids in their hemagglutinin cleavage site and thereby became highly pathogenic to chickens in 2017. previous studies indicated that these highly pathogenic h7n9 viruses are virulent in chickens but have distinct pathotypes in mice. a/chicken/guangdong/sd098/2017 (ck/sd098) is avirulent, with a 50% mouse lethal dose (mld50) of >7.5 log10 50% egg infectious dose (eid50), whereas a/chicken/hunan/s122 ...202031666373
detection of pb2 627 k mutation in two highly pathogenic isolates of the h7n9 subtype influenza a virus from chickens in northern china. 202032828821
continuous reassortment of clade 2.3.4.4 h5n6 highly pathogenetic avian influenza viruses demonstrating high risk to public health.since it firstly emerged in china in 2013, clade 2.3.4.4 h5n6 highly pathogenic avian influenza viruses (hpaivs) has rapidly replaced predominant h5n1 to become the dominant h5 subtype in china, especially in ducks. not only endemic in china, it also crossed the geographical barrier and emerged in south korea, japan, and europe. here, we analyzed the genetic properties of the clade 2.3.4.4 h5n6 hpaivs with full genome sequences available online together with our own isolates. phylogenetic analys ...202032824873
immunogenicity and efficacy comparison of mdck cell-based and egg-based live attenuated influenza vaccines of h5 and h7 subtypes in ferrets.during a pandemic, the availability of specific pathogen free chicken eggs is a major bottleneck for up-scaling response to the demand for influenza vaccine. this has led us to explore the use of madin-darby canine kidney (mdck) cells for the manufacture of live attenuated influenza vaccine (laiv) that provides production flexibility and speed. the present study reports the comparison of the immunogenicity and efficacy of two mdck-based laivs against two egg-based laivs prepared from the same pa ...202032741671
contribution of segment 3 to the acquisition of virulence in contemporary h9n2 avian influenza viruses.h9n2 avian influenza viruses (aivs) circulate in poultry throughout much of asia, the middle east, and africa. these viruses cause huge economic damage to poultry production systems and pose a zoonotic threat both in their own right and in the generation of novel zoonotic viruses, for example, h7n9. in recent years, it has been observed that h9n2 viruses have further adapted to gallinaceous poultry, becoming more highly transmissible and causing higher morbidity and mortality. here, we investiga ...202032727875
emergence of human avian influenza a(h7n9) virus infections in wenshan city in southwest china, 2017.the emergence of human infection with avian influenza a(h7n9) virus was reported in wenshan city, southwestern china in 2017. the study describes the epidemiological and virological features of the outbreak and discusses the origin of the infection.202032075579
role of the hemagglutinin residue 227 in immunogenicity of h5 and h7 subtype avian influenza vaccines in chickens.many h5 and h7 subtype avian influenza vaccines are poorly immunogenic in terms of inducing hemagglutination-inhibition (hi) antibody titers. residue 227 (h3 numbering) in the receptor binding site in the hemagglutinin (ha) is critical for the detectability of hi antibodies induced by h5 influenza vaccines. however, whether the effect of residue 227 on immunogenicity can be generalized in different subtypes is unclear. in this study, the impact of ha residue 227 on immunogenicity of h5n1, h5n6, ...202033347548
establishing a multicolor flow cytometry to characterize cellular immune response in chickens following h7n9 avian influenza virus infection.avian influenza virus (aiv) emerged and has continued to re-emerge, continuously posing great threats to animal and human health. the detection of hemagglutination inhibition (hi) or virus neutralization antibodies (na) is essential for assessing immune protection against aiv. however, the hi/na-independent immune protection is constantly observed in vaccines' development against h7n9 subtype aiv and other subtypes in chickens and mammals, necessitating the analysis of the cellular immune respon ...202033291218
dominant subtype switch in avian influenza viruses during 2016-2019 in china.we have surveyed avian influenza virus (aiv) genomes from live poultry markets within china since 2014. here we present a total of 16,091 samples that were collected from may 2016 to february 2019 in 23 provinces and municipalities in china. we identify 2048 aiv-positive samples and perform next generation sequencing. aiv-positive rates (12.73%) from samples had decreased substantially since 2016, compared to that during 2014-2016 (26.90%). additionally, h9n2 has replaced h5n6 and h7n9 as the do ...202033219213
transcriptome profiles of highly pathogenic pure avian h7n9 virus-infected lungs of balb/c mice.avian influenza a (h7n9) viruses emerged in china in 2013 and caused a zoonotic disease associated with a high case-fatality ratio of more than 30%. transcriptional profiles obtained using animal models reveal host responses to the disease, thereby providing insights into disease pathogenesis. therefore, we aimed to characterize the host responses of the h7n9 virus infected-mouse lungs in this study. first, we isolated an avian-originated h7n9 strain, which was shown to be highly pathogenic to b ...202033409298
interleukin 12-containing influenza virus-like-particle vaccine elevate its protective activity against heterotypic influenza virus infection.to produce monovalent and bivalent influenza vaccines composed of virus-like particles (vlps) containing hemagglutinin (ha), we generated four recombinant baculoviruses derived from bombyx mori nuclear polyhedrosis virus (bmnpv) and autographa california nuclear polyhedrosis virus (acnpv). monovalent fukushima (a/tufted duck/fukushima/16/2011 [h5n1]) (fkh5) and anhui (a/anhui/1/2013 [h7n9]) (anh7) vlp influenza vaccines were produced in silkworm pupae infected with fkh5-bmnpv or anh7-bmnpv. to p ...202032802975
molecular characteristics of h9n2 influenza viruses isolated from farmed raccoon dogs and arctic foxes in china.in this study, eight h9n2 iavs were isolated from infected diseased, farmed raccoon dogs and arctic foxes. eight genes shared 98.6%-100% identity among the isolates possessing a psrssr/gl motif at the ha cleavage site, which is same as the motif of g1 and y280 lineages of h9n2 iavs. the phylogenetic analysis showed that the ha genes of the eight isolates clustered with y280-like viruses, whereas the na genes belonged to f/98-like sublineage. interestingly, the ns, np, pb2 and pa genes of the iso ...202033223121
the pb2 co-adaptation of h10n8 avian influenza virus increases the pathogenicity to chickens and mice.avian influenza (ai) is an important zoonotic disease, which can be transmitted across species barriers to other hosts, especially humans, posing a serious threat to the poultry industry and public health. in recent years, human cases infected with the h10n8, h9n2, and h7n9 of avian influenza viruses (aivs) have been identified frequently as have the internal genes of h7n9 and h10n8, which are derived from h9n2 viruses. the adaptive mutation of the pb2 gene is an important way for the h10n8, h9n ...202134008327
h7n9 influenza virus-like particle based on bevs protects chickens from lethal challenge with highly pathogenic h7n9 avian influenza virus.h7n9 avian influenza virus poses a dual threat to both poultry industry and public health. therefore, it is highly urgent to develop an effective vaccine to reduce its pandemic potential. virus-like particles (vlp) represent an effective approach for pandemic vaccine development. in this study, a recombinant baculovirus co-expressing the ha, na and m1 genes of the h7n9 virus was constructed for generation of h7n9 vlp. single immunization of chickens with 15 μg of the vlp or the commercial whole ...202134004568
h9n2 influenza virus spillover into wild birds from poultry in china bind to human-type receptors and transmit in mammals via respiratory droplets.h9n2 influenza virus has been reported worldwide for several decades, and it has evolved into multiple genotypes among domestic poultry. however, the study involving ecology and evolution of low pathogenic avian influenza virus h9n2 in wild birds in china is limited. here, we carried out surveillance of avian influenza virus h9n2 in wild birds along with the east asian-australian migratory flyway in china in 2017. to estimate the prevalence of h9n2 avian virus in wild birds, information on expos ...202133566453
virus adaptation following experimental infection of chickens with a domestic duck low pathogenic avian influenza isolate from the 2017 usa h7n9 outbreak identifies polymorphic mutations in multiple gene segments.in march 2017, highly pathogenic (hp) and low pathogenic (lp) avian influenza virus (aiv) subtype h7n9 were detected from poultry farms and backyard birds in several states in the southeast united states. because interspecies transmission is a known mechanism for evolution of aivs, we sought to characterize infection and transmission of a domestic duck-origin h7n9 lpaiv in chickens and genetically compare the viruses replicating in the chickens to the original h7n9 clinical field samples used as ...202134207098
development of an immunochromatographic strip for rapid detection of h7 subtype avian influenza viruses.h7n9 avian influenza virus (aiv) including highly and low pathogenic viruses have been detected in china since 2013. h7n9 aiv has a high mortality rate after infection in humans, and most human cases have close contacted with poultry in the live poultry market. therefore, it is necessary to develop a rapid point-of-care testing (poct) technique for h7n9 aiv detection.202133827632
reassortment with dominant chicken h9n2 influenza virus contributed to the fifth h7n9 virus human epidemic.h9n2 avian influenza virus (aiv) is regarded as a principal donor of viral genes through reassortment to co-circulating influenza viruses that can result in zoonotic reassortants. whether h9n2 virus can maintain sustained evolutionary impact on such reassortants is unclear. since 2013, avian h7n9 virus had caused five sequential human epidemics in china; the fifth wave in 2016-2017 was by far the largest but the mechanistic explanation behind the scale of infection is not clear. here, we found t ...202133731452
a live attenuated h9n2 avian influenza vaccine prevents the viral reassortment by exchanging the ha and ns1 packaging signals.the h9n2 avian influenza virus is not only an important zoonotic pathogen, it can also easily recombine with other subtypes to generate novel reassortments, such as the h7n9 virus. although h9n2 live attenuated vaccines can provide good multiple immunities, including humoral, cellular, and mucosal immunity, the risk of reassortment between the vaccine strain and wild-type virus is still a concern. here, we successfully rescued an h9n2 live attenuated strain [rtx-ns1-128 (mut)] that can interdict ...202133613465
g1-like m and pb2 genes are preferentially incorporated into h7n9 progeny virions during genetic reassortment.genotype s h9n2 viruses have become predominant in poultry in china since 2010. these viruses frequently donate their whole internal gene segments to other emerging influenza a subtypes such as the novel h7n9, h5n6, and h10n8 viruses. we recently reported that the pb2 and m genes of the genotype s h9n2 virus, which are derived from the g1-like virus, enhance the fitness of h5nx and h7n9 avian influenza viruses in chickens and mice. however, whether the g1-like pb2 and m genes are preferentially ...202133588843
a risk marker of tribasic hemagglutinin cleavage site in influenza a (h9n2) virus.low pathogenic avian influenza a(h9n2) virus is endemic worldwide and continually recruit internal genes to generate human-infecting h5n1, h5n6, h7n9, and h10n8 influenza variants. here we show that hemagglutinin cleavage sites (hacs) of h9n2 viruses tended to mutate towards hydrophilic via evolutionary transition, and the tribasic hacs were found at high prevalence in asia and the middle east. our finding suggested that the tribasic h9n2 viruses increased the viral replication, stability, patho ...202133452423
molecular characteristics of the h9n2 avian influenza viruses in live poultry markets in anhui province, china, 2013 to 2018.h9n2 subtype avian influenza virus (aiv) has low-pathogenicity but causes respiratory symptoms and drop in egg production in chicken with long-term virus shedding, resulting in great economic losses due to high mortality related to secondary infection with other pathogens. in recent years, h9n2 viruses have been posing a threat to public health, causing human infection in china. compared to studies on other aiv subtypes, there are relatively few studies on the pathogenic mechanism of the h9n2 vi ...202133437876
egyptian fruit bats (rousettus aegyptiacus) were resistant to experimental inoculation with avian-origin influenza a virus of subtype h9n2, but are susceptible to experimental infection with bat-borne h9n2 virus.influenza a viruses (iav) of subtype h9n2, endemic in world-wide poultry holdings, are reported to cause spill-over infections to pigs and humans and have also contributed substantially to recent reassortment-derived pre-pandemic zoonotic viruses of concern, such as the asian h7n9 viruses. recently, a h9n2 bat influenza a virus was found in egyptian fruit bats (rousettus aegyptiacus), raising the question of whether this bat species is a suitable host for iav. here, we studied the susceptibility ...202133919890
identification of the dominant non-neutralizing epitope in the haemagglutinin of h7n9 avian influenza virus.h7n9 avian influenza vaccines induce high levels of non-neutralizing (nonneu) antibodies against the haemagglutinin (ha). however, the antigenic epitopes underlying this particular antibody response are still undefined. in this study, a panel of 13 monoclonal antibodies (mabs) against the ha protein of h7n9 virus was generated and 12 of them had no hemagglutination inhibition and virus neutralizing activities. one linear epitope in the stalk (373-taa-375) recognized by three mabs and one conform ...202133819520
genetic and biological properties of h7n9 avian influenza viruses detected after application of the h7n9 poultry vaccine in china.the h7n9 avian influenza virus (aiv) that emerged in china have caused five waves of human infection. further human cases have been successfully prevented since september 2017 through the use of an h7n9 vaccine in poultry. however, the h7n9 aiv has not been eradicated from poultry in china, and its evolution remains largely unexplored. in this study, we isolated 19 h7n9 aivs during surveillance and diagnosis from february 2018 to december 2019, and genetic analysis showed that these viruses have ...202133905456
pathogenesis and genetic characteristics of a novel reassortant low pathogenic avian influenza a(h7n6) virus isolated in cambodia in 2019.the first human case of zoonotic a(h7n4) avian influenza virus (aiv) infection was reported in early 2018 in china. two months after this case, novel a(h7n4) viruses phylogenetically related to the jiangsu isolate emerged in ducks from live bird markets in cambodia. during active surveillance in cambodia, a novel a(h7n6) reassortant of the zoonotic low pathogenic aiv (lpaiv) a(h7n4) was detected in domestic ducks at a slaughterhouse. complete genome sequencing and phylogenetic analysis showed th ...202134347386
efficacy of a cap-dependent endonuclease inhibitor and neuraminidase inhibitors against h7n9 highly pathogenic avian influenza virus causing severe viral pneumonia in cynomolgus macaques.h7n9 highly pathogenic avian influenza virus (hpaiv) infection in a human was first reported in 2017. a/duck/japan/aq-he29-22/2017 (h7n9) (dk/he29-22), found in imported duck meat at an airport in japan, possesses a hemagglutinin with a multibasic cleavage site, indicating high pathogenicity in chickens, as in the case of other h7 hpaivs. in the present study, we examined the pathogenicity of dk/he29-22 and the effectiveness of a cap-dependent endonuclease inhibitor (baloxavir) and neuraminidase ...202133257455
genetic analysis of genotype g57 h9n2 avian influenza virus isolate a/chicken/tajikistan/2379/2018 recovered in central asia.this paper presents genetic data on the full genome analysis of a/chicken/tajikistan/2379/2018 h9n2 influenza virus isolated in september 2018 from chicken pathological material received from poultry farms of the republic of tajikistan and subtyped as h9n2 by serological and molecular methods. according to the results of hemagglutinin gene sequencing, the amino acid sequence of the cleavage site was rssr/glf, which is typical for low-virulent avian influenza virus. phylogenetic analysis of the n ...202133740120
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