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1.
Int J Infect Dis ; : 107146, 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38945434

RESUMO

OBJECTIVE: This study sought to detect and characterize influenza A (IAV) and influenza D (IDV) viruses circulating among commercial birds and shop owners in Pakistan's live bird markets. METHODS: Oropharyngeal swabs (n=600; n=300 pools) collected from poultry and nasopharyngeal swabs (n=240) collected from poultry workers were studied for molecular evidence of IAV and IDV using real-time and conventional RT-PCR protocols. RESULTS: Nineteen (6.3%) poultry pools were positive for IAV and 73.9% of these were positive for H9N2 subtypes. Two (0.83%) poultry workers had evidence of IAV, and both were also H9N2 subtypes. The poultry and human influenza A-positive specimens all clustered phylogenetically by Sanger and next-generation sequencing with previously detected H9N2 poultry isolates. No field specimens were positive for IDV. CONCLUSION: H9N2 IAV is likely enzootic in Punjab Province Pakistan's live bird markets and may be colonizing the noses of workers and market visitors. Regular monitoring for avian influenza-associated human illness in Punjab seems to be a needed public measure.

2.
Nat Commun ; 15(1): 4350, 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38782954

RESUMO

mRNA lipid nanoparticle (LNP) vaccines would be useful during an influenza virus pandemic since they can be produced rapidly and do not require the generation of egg-adapted vaccine seed stocks. Highly pathogenic avian influenza viruses from H5 clade 2.3.4.4b are circulating at unprecedently high levels in wild and domestic birds and have the potential to adapt to humans. Here, we generate an mRNA lipid nanoparticle (LNP) vaccine encoding the hemagglutinin (HA) glycoprotein from a clade 2.3.4.4b H5 isolate. The H5 mRNA-LNP vaccine elicits strong T cell and antibody responses in female mice, including neutralizing antibodies and broadly-reactive anti-HA stalk antibodies. The H5 mRNA-LNP vaccine elicits antibodies at similar levels compared to whole inactivated vaccines in female mice with and without prior H1N1 exposures. Finally, we find that the H5 mRNA-LNP vaccine is immunogenic in male ferrets and prevents morbidity and mortality of animals following 2.3.4.4b H5N1 challenge. Together, our data demonstrate that a monovalent mRNA-LNP vaccine expressing 2.3.4.4b H5 is immunogenic and protective in pre-clinical animal models.


Assuntos
Anticorpos Antivirais , Furões , Glicoproteínas de Hemaglutininação de Vírus da Influenza , Virus da Influenza A Subtipo H5N1 , Vacinas contra Influenza , Nanopartículas , Infecções por Orthomyxoviridae , Vacinas de mRNA , Animais , Vacinas contra Influenza/imunologia , Vacinas contra Influenza/administração & dosagem , Feminino , Camundongos , Nanopartículas/química , Masculino , Virus da Influenza A Subtipo H5N1/imunologia , Virus da Influenza A Subtipo H5N1/genética , Anticorpos Antivirais/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Infecções por Orthomyxoviridae/prevenção & controle , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/virologia , Vacinas de mRNA/imunologia , Anticorpos Neutralizantes/imunologia , Camundongos Endogâmicos BALB C , Influenza Aviária/prevenção & controle , Influenza Aviária/imunologia , Influenza Aviária/virologia , Humanos , RNA Mensageiro/genética , RNA Mensageiro/imunologia , RNA Mensageiro/metabolismo , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H1N1/genética , Aves/virologia , Lipídeos/química , Lipossomos
3.
J Infect Dis ; 2023 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-37770028

RESUMO

The antiviral susceptibility of currently circulating (2022-2023) highly pathogenic avian influenza (HPAI) A(H5N1) viruses was assessed by genotypic and phenotypic approaches. The frequency of neuraminidase (NA) and polymerase acidic (PA) substitutions associated with reduced inhibition by NA inhibitors (NAIs) (21/2698, 0.78%) or by the PA inhibitor baloxavir (14/2600, 0.54%) was low. Phenotypic testing of 22 clade 2.3.2.1a and 2.3.4.4b viruses revealed broad susceptibility to NAIs and baloxavir concluding that most contemporary HPAI A(H5N1) viruses retain susceptibility to antiviral drugs. Novel NA-K432E and NA-T438I substitutions (N2 numbering) were identified at elevated frequencies (104/2698, 3.85%) and caused reduced zanamivir and peramivir inhibition.

4.
Nat Commun ; 14(1): 3082, 2023 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-37248261

RESUMO

Highly pathogenic avian influenza A(H5N1) viruses of clade 2.3.4.4b underwent an explosive geographic expansion in 2021 among wild birds and domestic poultry across Asia, Europe, and Africa. By the end of 2021, 2.3.4.4b viruses were detected in North America, signifying further intercontinental spread. Here we show that the western movement of clade 2.3.4.4b was quickly followed by reassortment with viruses circulating in wild birds in North America, resulting in the acquisition of different combinations of ribonucleoprotein genes. These reassortant A(H5N1) viruses are genotypically and phenotypically diverse, with many causing severe disease with dramatic neurologic involvement in mammals. The proclivity of the current A(H5N1) 2.3.4.4b virus lineage to reassort and target the central nervous system warrants concerted planning to combat the spread and evolution of the virus within the continent and to mitigate the impact of a potential influenza pandemic that could originate from similar A(H5N1) reassortants.


Assuntos
Virus da Influenza A Subtipo H5N1 , Vírus da Influenza A , Influenza Aviária , Influenza Humana , Animais , Humanos , Influenza Humana/epidemiologia , Influenza Aviária/epidemiologia , Virus da Influenza A Subtipo H5N1/genética , Animais Selvagens , Aves , Aves Domésticas , Filogenia , Mamíferos
5.
Emerg Infect Dis ; 28(12): 2534-2537, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36417959

RESUMO

In August 2021, we detected highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b viruses in poultry in southern Benin. The isolates were genetically similar to H5N1 viruses of clade 2.3.4.4b isolated during the same period in Africa and Europe. We also found evidence for 2 separate introductions of these viruses into Benin.


Assuntos
Virus da Influenza A Subtipo H5N1 , Influenza Aviária , Influenza Humana , Animais , Humanos , Aves Domésticas , Influenza Aviária/epidemiologia , Benin/epidemiologia , Filogenia , Aves
6.
Viruses ; 14(7)2022 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-35891464

RESUMO

From 2010 to 2013, genotype I avian influenza A(H9N2) viruses of the G1-lineage were isolated from several poultry species in Egypt. In 2014, novel reassortant H9N2 viruses were detected in pigeons designated as genotype II. To monitor the subsequent genetic evolution of Egyptian A(H9N2) viruses, we characterized the full genomes of 173 viruses isolated through active surveillance from 2017 to 2022. In addition, we compared the virological characteristics and pathogenicity of representative viruses. Phylogenetic analysis of the HA indicated that all studied sequences from 2017-2021 were grouped into G1-like H9N2 viruses previously detected in Egypt. Phylogenetic analysis indicated that the Egyptian A(H9N2) viruses had undergone further reassortment, inheriting four genes (PB2, PB1, PA, NS) from genotype II, with their remaining segments deriving from genotype I viruses (these viruses designated as genotype III). Studying the virological features of the two most dominant genotypes (I and III) of Egyptian H9N2 viruses in vitro and in vivo indicated that both replicated well in mammalian cells, but did not show any clinical signs in chickens, ducks, and mice. Monitoring avian influenza viruses through surveillance programs and understanding the genetic and antigenic characteristics of circulating H9N2 viruses are essential for risk assessment and influenza pandemic preparedness.


Assuntos
Vírus da Influenza A Subtipo H9N2 , Influenza Aviária , Influenza Humana , Animais , Galinhas , Egito/epidemiologia , Humanos , Influenza Aviária/epidemiologia , Mamíferos , Camundongos , Filogenia , Vírus Reordenados
7.
Viruses ; 14(6)2022 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-35746770

RESUMO

Despite the yearly global impact of influenza B viruses (IBVs), limited host range has been a hurdle to developing a readily accessible small animal disease model for vaccine studies. Mouse-adapting IBV can produce highly pathogenic viruses through serial lung passaging in mice. Previous studies have highlighted amino acid changes throughout the viral genome correlating with increased pathogenicity, but no consensus mutations have been determined. We aimed to show that growth system can play a role in mouse-adapted IBV lethality. Two Yamagata-lineage IBVs were serially passaged 10 times in mouse lungs before expansion in embryonated eggs or Madin-Darby canine kidney cells (London line) for use in challenge studies. We observed that virus grown in embryonated eggs was significantly more lethal in mice than the same virus grown in cell culture. Ten additional serial lung passages of one strain again showed virus grown in eggs was more lethal than virus grown in cells. Additionally, no mutations in the surface glycoprotein amino acid sequences correlated to differences in lethality. Our results suggest growth system can influence lethality of mouse-adapted IBVs after serial lung passaging. Further research can highlight improved mechanisms for developing animal disease models for IBV vaccine research.


Assuntos
Vacinas contra Influenza , Infecções por Orthomyxoviridae , Sequência de Aminoácidos , Animais , Cães , Ovos , Vírus da Influenza B/genética , Células Madin Darby de Rim Canino , Camundongos , Camundongos Endogâmicos BALB C
8.
Microorganisms ; 10(3)2022 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-35336170

RESUMO

In Egypt, the endemicity of avian influenza viruses is a serious concern. Since 2016, several outbreaks of H5N8 have been recorded among domestic poultry in various areas of the country. Active surveillance of domestic poultry across several governorates in Egypt from 2017 to 2021 detected at least six genotypes of Highly Pathogenic Avian Influenza (HPAI) H5N8 viruses with evidence of partial or complete annual replacement of dominant strains. Although all Egyptian H5N8 viruses had clade 2.3.4.4b hemagglutinin (HA) genes, the remaining viral gene segments were from multiple geographic origins, indicating that the H5N8 isolates resulted from multiple introductions. Mutations in the viral proteins associated with pathogenicity and antiviral drug resistance were detected. Some mutations in the HA resulted in antigenic drift. Heterogeneity in circulating H5N8 HPAI threatens poultry production and public health.

9.
Viruses ; 14(3)2022 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-35336936

RESUMO

Low pathogenic H9N2 avian influenza (LPAI H9N2) is considered one of the most important diseases found in poultry (broiler, laying hens, breeding chickens, and turkeys). This infection causes considerable economic losses. The objective of this work was to monitor and assess the presence of avian influenza virus (AIV) H9N2 in eight different regions of Morocco using real-time RT-PCR, and to assess the phylogenetic and molecular evolution of the H9N2 viruses between 2016 and 2019. Field samples were collected from 108 farms suspected of being infected with LPAI H9N2 virus. Samples were analyzed using H9N2-specific real-time RT-PCR. Highly positive samples were subjected to virus isolation and seven isolates were fully sequenced. Low pathogenic H9N2 avian influenza virus was introduced in Morocco in 2016. We show that in 2018-2019, the virus was still present irrespective of vaccination status. Phylogenetic and molecular analyses showed mutations related to virulence, although our viruses were related to 2016 Moroccan viruses and grouped in the G1 lineage. Specific amino acid substitutions were identified in Moroccan H9N2 viruses that are believed to lead to increased resistance to antiviral drugs.


Assuntos
Vírus da Influenza A Subtipo H9N2 , Influenza Aviária , Doenças das Aves Domésticas , Animais , Galinhas , Feminino , Influenza Aviária/epidemiologia , Marrocos/epidemiologia , Filogenia , Doenças das Aves Domésticas/epidemiologia
10.
Nat Microbiol ; 6(11): 1455-1465, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34702977

RESUMO

Understanding the evolutionary adaptations that enable avian influenza viruses to transmit in mammalian hosts could allow better detection of zoonotic viruses with pandemic potential. We applied ancestral sequence reconstruction to gain viruses representing different adaptive stages of the European avian-like (EA) H1N1 swine influenza virus as it transitioned from avian to swine hosts since 1979. Ancestral viruses representing the avian-like precursor virus and EA swine influenza viruses from 1979-1983, 1984-1987 and 1988-1992 were reconstructed and characterized. Glycan-binding analyses showed stepwise changes in the haemagglutinin receptor-binding specificity of the EA swine influenza viruses-that is, from recognition of both α2,3- and α2,6-linked sialosides to recognition of α2,6-linked sialosides only; however, efficient transmission in piglets was enabled by adaptive changes in the viral polymerase protein and nucleoprotein, which have been fixed since 1983. PB1-Q621R and NP-R351K increased viral replication and transmission in piglets when introduced into the 1979-1983 ancestral virus that lacked efficient transmissibility. The stepwise adaptation of an avian influenza virus to a mammalian host suggests that there may be opportunities to intervene and prevent interspecies jumps through strategic coordination of surveillance and risk assessment activities.


Assuntos
Adaptação Fisiológica , Vírus da Influenza A Subtipo H1N1/fisiologia , Influenza Aviária/virologia , Infecções por Orthomyxoviridae/veterinária , Doenças dos Suínos/virologia , Animais , Aves , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Vírus da Influenza A Subtipo H1N1/classificação , Vírus da Influenza A Subtipo H1N1/genética , Influenza Aviária/transmissão , Infecções por Orthomyxoviridae/metabolismo , Infecções por Orthomyxoviridae/transmissão , Infecções por Orthomyxoviridae/virologia , Filogenia , Polissacarídeos/química , Polissacarídeos/metabolismo , Receptores Virais/química , Receptores Virais/metabolismo , Suínos , Doenças dos Suínos/metabolismo , Doenças dos Suínos/transmissão , Replicação Viral
11.
Viruses ; 13(4)2021 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-33918166

RESUMO

Genetic analysis of circulating avian influenza viruses (AIVs) in wild birds at different geographical regions during the same period could improve our knowledge about virus transmission dynamics in natural hosts, virus evolution as well as zoonotic potential. Here, we report the genetic and molecular characterization of H6N2 influenza viruses isolated from migratory birds in Turkey, Egypt, and Uganda during 2017-2018. The Egyptian and Turkish isolates were genetically closer to each other than they were to the virus isolated from Uganda. Our results also suggest that multiple reassortment events were involved in the genesis of the isolated viruses. All viruses contained molecular markers previously associated with increased replication and/or pathogenicity in mammals. The results of this study indicate that H6N2 viruses carried by migratory birds on the West Asian/East African and Mediterranean/Black Sea flyways have the potential to transmit to mammals including humans. Additionally, adaptation markers in these viruses indicate the potential risk for poultry, which also increases the possibility of human exposure to these viruses.


Assuntos
Vírus da Influenza A/classificação , Vírus da Influenza A/genética , Influenza Aviária/virologia , Filogenia , Vírus Reordenados/genética , Migração Animal , Animais , Animais Selvagens/virologia , Galinhas/virologia , Egito , Genoma Viral , Humanos , Vírus da Influenza A/isolamento & purificação , Influenza Aviária/transmissão , Aves Domésticas/virologia , Turquia , Uganda
12.
Emerg Microbes Infect ; 10(1): 753-761, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33754959

RESUMO

Sub-Saharan Africa was historically considered an animal influenza cold spot, with only sporadic highly pathogenic H5 outbreaks detected over the last 20 years. However, in 2017, low pathogenic avian influenza A(H9N2) viruses were detected in poultry in Sub-Saharan Africa. Molecular, phylogenetic, and antigenic characterization of isolates from Benin, Togo, and Uganda showed that they belonged to the G1 lineage. Isolates from Benin and Togo clustered with viruses previously described in Western Africa, whereas viruses from Uganda were genetically distant and clustered with viruses from the Middle East. Viruses from Benin exhibited decreased cross-reactivity with those from Togo and Uganda, suggesting antigenic drift associated with reduced replication in Calu-3 cells. The viruses exhibited mammalian adaptation markers similar to those of the human strain A/Senegal/0243/2019 (H9N2). Therefore, viral genetic and antigenic surveillance in Africa is of paramount importance to detect further evolution or emergence of new zoonotic strains.


Assuntos
Vírus da Influenza A Subtipo H9N2/genética , Vírus da Influenza A Subtipo H9N2/imunologia , Influenza Aviária/virologia , Doenças das Aves Domésticas/virologia , África Subsaariana , Animais , Anticorpos Antivirais/imunologia , Variação Antigênica , Galinhas/virologia , Reações Cruzadas , Evolução Molecular , Humanos , Vírus da Influenza A Subtipo H9N2/patogenicidade , Vírus da Influenza A Subtipo H9N2/fisiologia , Influenza Humana/virologia , Filogenia , Virulência , Replicação Viral
13.
Nat Commun ; 12(1): 1203, 2021 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-33619277

RESUMO

Influenza A virus infection in swine impacts the agricultural industry in addition to its zoonotic potential. Here, we utilize epigraph, a computational algorithm, to design a universal swine H3 influenza vaccine. The epigraph hemagglutinin proteins are delivered using an Adenovirus type 5 vector and are compared to a wild type hemagglutinin and the commercial inactivated vaccine, FluSure. In mice, epigraph vaccination leads to significant cross-reactive antibody and T-cell responses against a diverse panel of swH3 isolates. Epigraph vaccination also reduces weight loss and lung viral titers in mice after challenge with three divergent swH3 viruses. Vaccination studies in swine, the target species for this vaccine, show stronger levels of cross-reactive antibodies and T-cell responses after immunization with the epigraph vaccine compared to the wild type and FluSure vaccines. In both murine and swine models, epigraph vaccination shows superior cross-reactive immunity that should be further investigated as a universal swH3 vaccine.


Assuntos
Algoritmos , Reações Cruzadas/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Imunidade , Vírus da Influenza A/imunologia , Vacinas contra Influenza/imunologia , Animais , Formação de Anticorpos/imunologia , Epitopos/imunologia , Feminino , Humanos , Influenza Humana/sangue , Influenza Humana/imunologia , Influenza Humana/virologia , Pulmão/patologia , Pulmão/virologia , Masculino , Camundongos Endogâmicos BALB C , Infecções por Orthomyxoviridae/sangue , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Infecções por Orthomyxoviridae/virologia , Suínos , Linfócitos T/imunologia , Vacinação , Redução de Peso
14.
J Virol ; 94(18)2020 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-32611750

RESUMO

Since its detection in swine, influenza D virus (IDV) has been shown to be present in multiple animal hosts, and bovines have been identified as its natural reservoir. However, it remains unclear how IDVs emerge, evolve, spread, and maintain in bovine populations. Through multiple years of virological and serological surveillance in a single order-buyer cattle facility in Mississippi, we showed consistently high seroprevalence of IDVs in cattle and recovered a total of 32 IDV isolates from both healthy and sick animals, including those with antibodies against IDV. Genomic analyses of these isolates along with those isolated from other areas showed that active genetic reassortment occurred in IDV and that five reassortants were identified in the Mississippian facility. Two antigenic groups were identified through antigenic cartography analyses for these 32 isolates and representative IDVs from other areas. Remarkably, existing antibodies could not protect cattle from experimental reinfection with IDV. Additional phenotypic analyses demonstrated variations in growth dynamics and pathogenesis in mice between viruses independent of genomic constellation. In summary, this study suggests that, in addition to epidemiological factors, the ineffectiveness of preexisting immunity and cocirculation of a diverse viral genetic pool could facilitate its high prevalence in animal populations.IMPORTANCE Influenza D viruses (IDVs) are panzootic in multiple animal hosts, but the underlying mechanism is unclear. Through multiple years of surveillance in the same order-buyer cattle facility, 32 IDV isolates were recovered from both healthy and sick animals, including those with evident antibodies against IDV. Active reassortment occurred in the cattle within this facility and in those across other areas, and multiple reassortants cocirculated in animals. These isolates are shown with a large extent of phenotypic diversity in replication efficiency and pathogenesis but little in antigenic properties. Animal experiments demonstrated that existing antibodies could not protect cattle from experimental reinfection with IDV. This study suggests that, in addition to epidemiological factors, limited protection from preexisting immunity against IDVs in cattle herds and cocirculation of a diverse viral genetic pool likely facilitate the high prevalence of IDVs in animal populations.


Assuntos
Anticorpos Antivirais/sangue , Proteção Cruzada , Genoma Viral , Infecções por Orthomyxoviridae/epidemiologia , Vírus Reordenados/imunologia , Thogotovirus/imunologia , Animais , Bovinos , Monitoramento Epidemiológico , Fazendas , Variação Genética , Genótipo , Hospitais Veterinários , Imunidade Inata , Camundongos , Mississippi/epidemiologia , Tipagem Molecular , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/virologia , Filogenia , Vírus Reordenados/classificação , Vírus Reordenados/genética , Vírus Reordenados/patogenicidade , Estudos Soroepidemiológicos , Thogotovirus/classificação , Thogotovirus/genética , Thogotovirus/patogenicidade , Replicação Viral
16.
Influenza Other Respir Viruses ; 13(6): 622-626, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31478603

RESUMO

In late 2017, increased mortality was detected in chicken farms in Algeria undergoing A(H9N2) influenza outbreaks. Analysis of viruses isolated from affected farms showed that they were monophyletic, were of the G1 hemagglutinin (HA) lineage, and were antigenically and genetically similar to viruses detected contemporaneously in other countries in Northern Africa and the Middle East. The virus was able to spread via contact transmission between ferrets but did not cause disease in intravenously inoculated chickens.


Assuntos
Surtos de Doenças/veterinária , Vírus da Influenza A Subtipo H9N2/fisiologia , Influenza Aviária/epidemiologia , Influenza Aviária/virologia , Argélia/epidemiologia , Animais , Galinhas , Fazendas , Furões , Testes de Inibição da Hemaglutinação/veterinária , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Vírus da Influenza A Subtipo H9N2/classificação , Vírus da Influenza A Subtipo H9N2/genética , Vírus da Influenza A Subtipo H9N2/imunologia , Influenza Aviária/diagnóstico , Influenza Aviária/transmissão , Neuraminidase/genética , Filogenia , Carga Viral/veterinária , Proteínas Virais/genética
17.
Proc Natl Acad Sci U S A ; 114(42): 11217-11222, 2017 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-28874549

RESUMO

North American wild birds are an important reservoir of influenza A viruses, yet the potential of viruses in this reservoir to transmit and cause disease in mammals is not well understood. Our surveillance of avian influenza viruses (AIVs) at Delaware Bay, USA, revealed a group of similar H1N1 AIVs isolated in 2009, some of which were airborne-transmissible in the ferret model without prior adaptation. Comparison of the genomes of these viruses revealed genetic markers of airborne transmissibility in the Polymerase Basic 2 (PB2), PB1, PB1-F2, Polymerase Acidic-X (PA-X), Nonstructural Protein 1 (NS1), and Nuclear Export Protein (NEP) genes. We studied the role of NS1 in airborne transmission and found that NS1 mutants that were not airborne-transmissible caused limited tissue pathology in the upper respiratory tract (URT). Viral maturation was also delayed, evident as strong intranuclear staining and little virus at the mucosa. Our study of this naturally occurring constellation of genetic markers has provided insights into the poorly understood phenomenon of AIV airborne transmissibility by revealing a role for NS1 and characteristics of viral replication in the URT that were associated with airborne transmission. The transmissibility of these viruses further highlights the pandemic potential of AIVs in the wild bird reservoir and the need to maintain surveillance.


Assuntos
Charadriiformes/virologia , Vírus da Influenza A Subtipo H1N1/patogenicidade , Infecções por Orthomyxoviridae/transmissão , Animais , Embrião de Galinha , Vetores de Doenças , Furões , Vírus da Influenza A Subtipo H1N1/genética , Masculino , Sistema Respiratório/virologia , Replicação Viral
18.
J Gen Virol ; 98(6): 1232-1244, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28631606

RESUMO

Among the diverse clades of highly pathogenic avian influenza (HPAI) H5N1 viruses of the goose/Guangdong lineage, only a few have been able to spread across continents: clade 2.2 viruses spread from China to Europe and into Africa in 2005-2006, clade 2.3.2.1 viruses spread from China to Eastern Europe in 2009-2010 and clade 2.3.4.4 viruses of the H5Nx subtype spread from China to Europe and North America in 2014/2015. While the poultry trade and wild-bird migration have been implicated in the spread of HPAI H5N1 viruses, it has been proposed that robust virus-shedding by wild ducks in the absence of overt clinical signs may have contributed to the wider dissemination of the clade 2.2, 2.3.2.1 and 2.3.4.4 viruses. Here we determined the phenotype of two divergent viruses from clade 2.3.2.1, a clade that spread widely, and two divergent viruses from clade 2.3.4, a clade that was constrained to Southeast Asia, in young (ducklings) and adult (juvenile) mallard ducks. We found that the virus-shedding magnitude and duration, transmission pattern and pathogenicity of the viruses in young and adult mallard ducks were largely independent of the virus clade. A clade-specific pattern could only be detected in terms of cumulative virus shedding, which was higher with clade 2.3.2.1 than with clade 2.3.4 viruses in juvenile mallards, but not in ducklings. The ability of clade 2.3.2.1c A/common buzzard/Bulgaria/38 WB/2010-like viruses to spread cross-continentally may, therefore, have been strain-specific or independent of phenotype in wild ducks.


Assuntos
Genótipo , Virus da Influenza A Subtipo H5N1/patogenicidade , Influenza Aviária/patologia , Influenza Aviária/virologia , Eliminação de Partículas Virais , África , Animais , Ásia , Patos , Europa (Continente) , Virus da Influenza A Subtipo H5N1/classificação , Virus da Influenza A Subtipo H5N1/genética , América do Norte , Fenótipo
19.
J Virol ; 90(17): 7647-56, 2016 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-27279619

RESUMO

UNLABELLED: We have previously shown that 11 patients became naturally coinfected with seasonal H1N1 (A/H1N1) and pandemic H1N1 (pdm/H1N1) during the Southern hemisphere winter of 2009 in New Zealand. Reassortment of influenza A viruses is readily observed during coinfection of host animals and in vitro; however, reports of reassortment occurring naturally in humans are rare. Using clinical specimen material, we show reassortment between the two coinfecting viruses occurred with high likelihood directly in one of the previously identified patients. Despite the lack of spread of these reassortants in the community, we did not find them to be attenuated in several model systems for viral replication and virus transmission: multistep growth curves in differentiated human bronchial epithelial cells revealed no growth deficiency in six recovered reassortants compared to A/H1N1 and pdm/H1N1 isolates. Two reassortant viruses were assessed in ferrets and showed transmission to aerosol contacts. This study demonstrates that influenza virus reassortants can arise in naturally coinfected patients. IMPORTANCE: Reassortment of influenza A viruses is an important driver of virus evolution, but little has been done to address humans as hosts for the generation of novel influenza viruses. We show here that multiple reassortant viruses were generated during natural coinfection of a patient with pandemic H1N1 (2009) and seasonal H1N1 influenza A viruses. Though apparently fit in model systems, these reassortants did not become established in the wider population, presumably due to herd immunity against their seasonal H1 antigen.


Assuntos
Coinfecção/virologia , Vírus da Influenza A Subtipo H1N1/crescimento & desenvolvimento , Vírus da Influenza A Subtipo H1N1/genética , Influenza Humana/virologia , Vírus Reordenados/crescimento & desenvolvimento , Vírus Reordenados/genética , Animais , Modelos Animais de Doenças , Células Epiteliais/virologia , Furões , Humanos , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Nova Zelândia , Infecções por Orthomyxoviridae/transmissão , Infecções por Orthomyxoviridae/virologia , Fenótipo , Vírus Reordenados/isolamento & purificação , Virulência , Replicação Viral
20.
J Virol ; 89(21): 10891-900, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26292325

RESUMO

UNLABELLED: Human infections with avian influenza viruses are a serious public health concern. The neuraminidase (NA) inhibitors (NAIs) are the frontline anti-influenza drugs and are the major option for treatment of newly emerging influenza. Therefore, it is essential to identify the molecular markers of NAI resistance among specific NA subtypes of avian influenza viruses to help guide clinical management. NAI-resistant substitutions in NA subtypes other than N1 and N2 have been poorly studied. Here, we identified NA amino acid substitutions associated with NAI resistance among influenza viruses of N3, N7, and N9 subtypes which have been associated with zoonotic transmission. We applied random mutagenesis and generated recombinant influenza viruses carrying single or double NA substitution(s) with seven internal genes from A/Puerto Rico/8/1934 (H1N1) virus. In a fluorescence-based NA inhibition assay, we identified three categories of NA substitutions associated with reduced inhibition by NAIs (oseltamivir, zanamivir, and peramivir): (i) novel subtype-specific substitutions in or near the enzyme catalytic site (R152W, A246T, and D293N, N2 numbering), (ii) subtype-independent substitutions (E119G/V and/or D and R292K), and (iii) substitutions previously reported in other subtypes (Q136K, I222M, and E276D). Our data show that although some markers of resistance are present across NA subtypes, other subtype-specific markers can only be determined empirically. IMPORTANCE: The number of humans infected with avian influenza viruses is increasing, raising concerns of the emergence of avian influenza viruses resistant to neuraminidase (NA) inhibitors (NAIs). Since most studies have focused on NAI-resistance in human influenza viruses, we investigated the molecular changes in NA that could confer NAI resistance in avian viruses grown in immortalized monolayer cells, especially those of the N3, N7, and N9 subtypes, which have caused human infections. We identified not only numerous NAI-resistant substitutions previously reported in other NA subtypes but also several novel changes conferring reduced susceptibility to NAIs, which are subtype specific. The findings indicate that some resistance markers are common across NA subtypes, but other markers need to be determined empirically for each subtype. The study also implies that antiviral surveillance monitoring could play a critical role in the clinical management of influenza virus infection and an essential component of pandemic preparedness.


Assuntos
Resistência a Medicamentos/genética , Inibidores Enzimáticos/farmacologia , Marcadores Genéticos/genética , Vírus da Influenza A/genética , Modelos Moleculares , Neuraminidase/antagonistas & inibidores , Animais , Cães , Engenharia Genética , Humanos , Vírus da Influenza A/efeitos dos fármacos , Células Madin Darby de Rim Canino , Mutagênese , Neuraminidase/química , Especificidade da Espécie , Ensaio de Placa Viral
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