RESUMO
Recently, A/H5N1 influenza viruses were shown to acquire airborne transmissibility between ferrets upon targeted mutagenesis and virus passage. The critical genetic changes in airborne A/Indonesia/5/05 were not yet identified. Here, five substitutions proved to be sufficient to determine this airborne transmission phenotype. Substitutions in PB1 and PB2 collectively caused enhanced transcription and virus replication. One substitution increased HA thermostability and lowered the pH of membrane fusion. Two substitutions independently changed HA binding preference from α2,3-linked to α2,6-linked sialic acid receptors. The loss of a glycosylation site in HA enhanced overall binding to receptors. The acquired substitutions emerged early during ferret passage as minor variants and became dominant rapidly. Identification of substitutions that are essential for airborne transmission of avian influenza viruses between ferrets and their associated phenotypes advances our fundamental understanding of virus transmission and will increase the value of future surveillance programs and public health risk assessments.
Assuntos
Virus da Influenza A Subtipo H5N1/fisiologia , Influenza Humana/transmissão , Influenza Humana/virologia , Substituição de Aminoácidos , Animais , Furões , Genoma Viral , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Humanos , Virus da Influenza A Subtipo H5N1/genética , Mutação , RNA Polimerase Dependente de RNA/química , RNA Polimerase Dependente de RNA/genética , RNA Polimerase Dependente de RNA/metabolismo , Receptores Virais/metabolismo , Seleção GenéticaRESUMO
Highly pathogenic avian influenza viruses (HPAIVs) cause severe hemorrhagic disease in terrestrial poultry and are a threat to the poultry industry, wild life, and human health. HPAIVs arise from low pathogenic avian influenza viruses (LPAIVs), which circulate in wild aquatic birds. HPAIV emergence is thought to occur in poultry and not wild aquatic birds, but the reason for this species-restriction is not known. We hypothesized that, due to species-specific tropism and replication, intrahost HPAIV selection is favored in poultry and disfavored in wild aquatic birds. We tested this hypothesis by co-inoculating chickens, representative of poultry, and ducks, representative of wild aquatic birds, with a mixture of H7N7 HPAIV and LPAIV, mimicking HPAIV emergence in an experimental setting. Virus selection was monitored in swabs and tissues by RT-qPCR and immunostaining of differential N-terminal epitope tags that were added to the hemagglutinin protein. HPAIV was selected in four of six co-inoculated chickens, whereas LPAIV remained the major population in co-inoculated ducks on the long-term, despite detection of infectious HPAIV in tissues at early time points. Collectively, our data support the hypothesis that HPAIVs are more likely to be selected at the intrahost level in poultry than in wild aquatic birds and point towards species-specific differences in HPAIV and LPAIV tropism and replication levels as possible explanations.
Assuntos
Vírus da Influenza A Subtipo H7N7 , Vírus da Influenza A , Influenza Aviária , Doenças das Aves Domésticas , Animais , Humanos , Galinhas , Patos , Vírus da Influenza A/genética , Animais Selvagens , Aves DomésticasRESUMO
Influenza B virus primarily infects humans, causing seasonal epidemics globally. Two antigenic variants-Victoria-like and Yamagata-like-were detected in the 1980s, of which the molecular basis of emergence is still incompletely understood. Here, the antigenic properties of a unique collection of historical virus isolates, sampled from 1962 to 2000 and passaged exclusively in mammalian cells to preserve antigenic properties, were determined with the hemagglutination inhibition assay and an antigenic map was built to quantify and visualize the divergence of the lineages. The antigenic map revealed only three distinct antigenic clusters-Early, Victoria, and Yamagata-with relatively little antigenic diversity in each cluster until 2000. Viruses with Victoria-like antigenic properties emerged around 1972 and diversified subsequently into two genetic lineages. Viruses with Yamagata-like antigenic properties evolved from one lineage and became clearly antigenically distinct from the Victoria-like viruses around 1988. Recombinant mutant viruses were tested to show that insertions and deletions (indels), as observed frequently in influenza B virus hemagglutinin, had little effect on antigenic properties. In contrast, amino-acid substitutions at positions 148, 149, 150, and 203, adjacent to the hemagglutinin receptor binding site, determined the main antigenic differences between the Early, Victoria-like, and Yamagata-like viruses. Surprisingly, substitutions at two of the four positions reverted in recent viruses of the Victoria lineage, resulting in antigenic properties similar to viruses circulating â¼50 y earlier. These data shed light on the antigenic diversification of influenza viruses and suggest there may be limits to the antigenic evolution of influenza B virus.
Assuntos
Influenza Humana , Animais , Variação Antigênica/genética , Sítios de Ligação , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Hemaglutininas , Humanos , Vírus da Influenza B/genética , Mamíferos , FilogeniaRESUMO
Recent human H3N2 influenza A viruses have evolved to employ elongated glycans terminating in α2,6-linked sialic acid as their receptors. These glycans are displayed in low abundancies by (humanized) Madin-Darby Canine Kidney cells, which are commonly employed to propagate influenza A virus, resulting in low or no viral propagation. Here, we examined whether the overexpression of the glycosyltransferases ß-1,3-N-acetylglucosaminyltransferase and ß-1,4-galactosyltransferase 1, which are responsible for the elongation of poly-N-acetyllactosamines (LacNAcs), would result in improved A/H3N2 propagation. Stable overexpression of ß-1,3-N-acetylglucosaminyltransferase and ß-1,4-galactosyltransferase 1 in Madin-Darby Canine Kidney and "humanized" Madin-Darby Canine Kidney cells was achieved by lentiviral integration and subsequent antibiotic selection and confirmed by qPCR and protein mass spectrometry experiments. Flow cytometry and glycan mass spectrometry experiments using the ß-1,3-N-acetylglucosaminyltransferase and/or ß-1,4-galactosyltransferase 1 knock-in cells demonstrated increased binding of viral hemagglutinins and the presence of a larger number of LacNAc repeating units, especially on "humanized" Madin-Darby Canine Kidney-ß-1,3-N-acetylglucosaminyltransferase cells. An increase in the number of glycan receptors did, however, not result in a greater infection efficiency of recent human H3N2 viruses. Based on these results, we propose that H3N2 influenza A viruses require a low number of suitable glycan receptors to infect cells and that an increase in the glycan receptor display above this threshold does not result in improved infection efficiency.
Assuntos
Vírus da Influenza A Subtipo H3N2 , Vírus da Influenza A , Humanos , Animais , Cães , Vírus da Influenza A Subtipo H3N2/metabolismo , N-Acetilglucosaminiltransferases/genética , N-Acetilglucosaminiltransferases/metabolismo , N-Acetil-Lactosamina Sintase/metabolismo , Glicoproteínas de Hemaglutininação de Vírus da Influenza , Vírus da Influenza A/metabolismo , Células Madin Darby de Rim Canino , Polissacarídeos/químicaRESUMO
Influenza A viruses of the H2N2 subtype sparked a pandemic in 1957 and circulated in humans until 1968. Because A/H2N2 viruses still circulate in wild birds worldwide and human population immunity is low, the transmissibility of six avian A/H2N2 viruses was investigated in the ferret model. None of the avian A/H2N2 viruses was transmitted between ferrets, suggesting that their pandemic risk may be low. The transmissibility, receptor binding preference and haemagglutinin (HA) stability of human A/H2N2 viruses were also investigated. Human A/H2N2 viruses from 1957 and 1958 bound to human-type α2,6-linked sialic acid receptors, but the 1958 virus had a more stable HA, indicating adaptation to replication and spread in the new host. This increased stability was caused by a previously unknown stability substitution G205S in the 1958 H2N2 HA, which became fixed in A/H2N2 viruses after 1958. Although individual substitutions were identified that affected the HA receptor binding and stability properties, they were not found to have a substantial effect on transmissibility of A/H2N2 viruses via the air in the ferret model. Our data demonstrate that A/H2N2 viruses continued to adapt during the first year of pandemic circulation in humans, similar to what was previously shown for the A/H1N1pdm09 virus.
Assuntos
Vírus da Influenza A Subtipo H2N2 , Vírus da Influenza A , Animais , Humanos , Vírus da Influenza A Subtipo H2N2/genética , Furões , PandemiasRESUMO
Low-pathogenic avian influenza viruses (LPAIVs) are genetically highly variable and have diversified into multiple evolutionary lineages that are primarily associated with wild-bird reservoirs. Antigenic variation has been described for mammalian influenza viruses and for highly pathogenic avian influenza viruses that circulate in poultry, but much less is known about antigenic variation of LPAIVs. In this study, we focused on H13 and H16 LPAIVs that circulate globally in gulls. We investigated the evolutionary history and intercontinental gene flow based on the hemagglutinin (HA) gene and used representative viruses from genetically distinct lineages to determine their antigenic properties by hemagglutination inhibition assays. For H13, at least three distinct genetic clades were evident, while for H16, at least two distinct genetic clades were evident. Twenty and ten events of intercontinental gene flow were identified for H13 and H16 viruses, respectively. At least two antigenic variants of H13 and at least one antigenic variant of H16 were identified. Amino acid positions in the HA protein that may be involved in the antigenic variation were inferred, and some of the positions were located near the receptor binding site of the HA protein, as they are in the HA protein of mammalian influenza A viruses. These findings suggest independent circulation of H13 and H16 subtypes in gull populations, as antigenic patterns do not overlap, and they contribute to the understanding of the genetic and antigenic variation of LPAIVs naturally circulating in wild birds.IMPORTANCE Wild birds play a major role in the epidemiology of low-pathogenic avian influenza viruses (LPAIVs), which are occasionally transmitted-directly or indirectly-from them to other species, including domestic animals, wild mammals, and humans, where they can cause subclinical to fatal disease. Despite a multitude of genetic studies, the antigenic variation of LPAIVs in wild birds is poorly understood. Here, we investigated the evolutionary history, intercontinental gene flow, and antigenic variation among H13 and H16 LPAIVs. The circulation of subtypes H13 and H16 seems to be maintained by a narrower host range, in particular gulls, than the majority of LPAIV subtypes and may therefore serve as a model for evolution and epidemiology of H1 to H12 LPAIVs in wild birds. The findings suggest that H13 and H16 LPAIVs circulate independently of each other and emphasize the need to investigate within-clade antigenic variation of LPAIVs in wild birds.
Assuntos
Variação Antigênica/genética , Vírus da Influenza A/genética , Influenza Aviária/genética , Animais , Animais Selvagens/virologia , Aves , Charadriiformes/virologia , Testes de Inibição da Hemaglutinação , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Hemaglutininas , Especificidade de Hospedeiro/genética , Vírus da Influenza A/imunologia , Vírus da Influenza A/patogenicidade , Influenza Aviária/imunologia , Influenza Aviária/virologia , Filogenia , Filogeografia/métodosRESUMO
Wild waterfowl form the main reservoir of influenza A viruses, from which transmission occurs directly or indirectly to various secondary hosts, including humans. Direct avian-to-human transmission has been observed for viruses of subtypes A(H5N1), A(H7N2), A(H7N3), A(H7N7), A(H9N2) and A(H10N7) upon human exposure to poultry, but a lack of sustained human-to-human transmission has prevented these viruses from causing new pandemics. Recently, avian A(H7N9) viruses were transmitted to humans, causing severe respiratory disease and deaths in China. Because transmission via respiratory droplets and aerosols (hereafter referred to as airborne transmission) is the main route for efficient transmission between humans, it is important to gain an insight into airborne transmission of the A(H7N9) virus. Here we show that although the A/Anhui/1/2013 A(H7N9) virus harbours determinants associated with human adaptation and transmissibility between mammals, its airborne transmissibility in ferrets is limited, and it is intermediate between that of typical human and avian influenza viruses. Multiple A(H7N9) virus genetic variants were transmitted. Upon ferret passage, variants with higher avian receptor binding, higher pH of fusion, and lower thermostability were selected, potentially resulting in reduced transmissibility. This A(H7N9) virus outbreak highlights the need for increased understanding of the determinants of efficient airborne transmission of avian influenza viruses between mammals.
Assuntos
Furões/virologia , Vírus da Influenza A/patogenicidade , Infecções por Orthomyxoviridae/transmissão , Infecções por Orthomyxoviridae/virologia , Microbiologia do Ar , Animais , Aves/virologia , Chlorocebus aethiops , Cães , Genoma Viral/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Humanos , Vírus da Influenza A/química , Vírus da Influenza A/classificação , Vírus da Influenza A/genética , Influenza Aviária/transmissão , Influenza Aviária/virologia , Influenza Humana/transmissão , Influenza Humana/virologia , Células Madin Darby de Rim Canino , Modelos Moleculares , Células VeroRESUMO
IntroductionHighly pathogenic avian influenza (HPAI) viruses of subtype H5N8 were re-introduced into the Netherlands by late 2016, after detections in south-east Asia and Russia. This second H5N8 wave resulted in a large number of outbreaks in poultry farms and the deaths of large numbers of wild birds in multiple European countries. Methods: Here we report on the detection of HPAI H5N8 virus in 57 wild birds of 12 species sampled during active (32/5,167) and passive (25/36) surveillance activities, i.e. in healthy and dead animals respectively, in the Netherlands between 8 November 2016 and 31 March 2017. Moreover, we further investigate the experimental approach of wild bird serology as a contributing tool in HPAI outbreak investigations. Results: In contrast to the first H5N8 wave, local virus amplification with associated wild bird mortality has occurred in the Netherlands in 2016/17, with evidence for occasional gene exchange with low pathogenic avian influenza (LPAI) viruses. Discussion: These apparent differences between outbreaks and the continuing detections of HPAI viruses in Europe are a cause of concern. With the current circulation of zoonotic HPAI and LPAI virus strains in Asia, increased understanding of the drivers responsible for the global spread of Asian poultry viruses via wild birds is needed.
Assuntos
Animais Selvagens/virologia , Aves/virologia , Surtos de Doenças/veterinária , Vírus da Influenza A Subtipo H5N8/isolamento & purificação , Vírus da Influenza A Subtipo H5N8/patogenicidade , Influenza Aviária/mortalidade , Animais , Vírus da Influenza A Subtipo H5N8/classificação , Vírus da Influenza A Subtipo H5N8/genética , Influenza Aviária/patologia , Influenza Aviária/virologia , Países Baixos/epidemiologia , RNA Viral/genética , Vigilância de Evento Sentinela , Análise de Sequência de DNARESUMO
Low pathogenic avian influenza A viruses (IAVs) have a natural host reservoir in wild waterbirds and the potential to spread to other host species. Here, we investigated the evolutionary, spatial and temporal dynamics of avian IAVs in Eurasian wild birds. We used whole-genome sequences collected as part of an intensive long-term Eurasian wild bird surveillance study, and combined this genetic data with temporal and spatial information to explore the virus evolutionary dynamics. Frequent reassortment and co-circulating lineages were observed for all eight genomic RNA segments over time. There was no apparent species-specific effect on the diversity of the avian IAVs. There was a spatial and temporal relationship between the Eurasian sequences and significant viral migration of avian IAVs from West Eurasia towards Central Eurasia. The observed viral migration patterns differed between segments. Furthermore, we discuss the challenges faced when analysing these surveillance and sequence data, and the caveats to be borne in mind when drawing conclusions from the apparent results of such analyses.
Assuntos
Evolução Molecular , Genoma Viral , Vírus da Influenza A/genética , Influenza Aviária/virologia , Filogenia , Migração Animal , Animais , Animais Selvagens/virologia , Aves/fisiologia , Aves/virologia , Vírus da Influenza A/classificação , Vírus da Influenza A/isolamento & purificação , Influenza Aviária/fisiopatologia , Dados de Sequência Molecular , Filogeografia , RNA Viral/genéticaRESUMO
We sampled 7,511 black-headed gulls for influenza virus in the Netherlands during 2006-2010 and found that subtypes H13 and H16 caused annual epidemics in fledglings on colony sites. Our findings validate targeted surveillance of wild waterbirds and clarify underlying factors for influenza virus emergence in other species.
Assuntos
Charadriiformes/virologia , Vírus da Influenza A/classificação , Influenza Aviária/epidemiologia , Animais , Feminino , Masculino , Países Baixos/epidemiologia , Prevalência , Vigilância em Saúde Pública , Estações do Ano , SorotipagemRESUMO
IMPORTANCE: A/H7 avian influenza viruses cause outbreaks in poultry globally, resulting in outbreaks with significant socio-economical impact and zoonotic risks. Occasionally, poultry vaccination programs have been implemented to reduce the burden of these viruses, which might result in an increased immune pressure accelerating antigenic evolution. In fact, evidence for antigenic diversification of A/H7 influenza viruses exists, posing challenges to pandemic preparedness and the design of vaccination strategies efficacious against drifted variants. Here, we performed a comprehensive analysis of the global antigenic diversity of A/H7 influenza viruses and identified the main substitutions in the hemagglutinin responsible for antigenic evolution in A/H7N9 viruses isolated between 2013 and 2019. The A/H7 antigenic map and knowledge of the molecular determinants of their antigenic evolution add value to A/H7 influenza virus surveillance programs, the design of vaccines and vaccination strategies, and pandemic preparedness.
Assuntos
Subtipo H7N9 do Vírus da Influenza A , Influenza Aviária , Influenza Humana , Animais , Humanos , Subtipo H7N9 do Vírus da Influenza A/genética , Hemaglutininas , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Variação Antigênica , Surtos de Doenças , Aves Domésticas , Influenza Aviária/epidemiologia , Influenza Aviária/prevenção & controle , Influenza Humana/epidemiologia , Influenza Humana/prevenção & controleRESUMO
Continued circulation of A/H5N1 influenza viruses of the A/goose/Guangdong/1/96 lineage in poultry has resulted in the diversification in multiple genetic and antigenic clades. Since 2009, clade 2.3.4.4 hemagglutinin (HA) containing viruses harboring the internal and neuraminidase (NA) genes of other avian influenza A viruses have been detected. As a result, various HA-NA combinations, such as A/H5N1, A/H5N2, A/H5N3, A/H5N5, A/H5N6, and A/H5N8 have been identified. As of January 2023, 83 humans have been infected with A/H5N6 viruses, thereby posing an apparent risk for public health. Here, as part of a risk assessment, the in vitro and in vivo characterization of A/H5N6 A/black-headed gull/Netherlands/29/2017 is described. This A/H5N6 virus was not transmitted between ferrets via the air but was of unexpectedly high pathogenicity compared to other described A/H5N6 viruses. The virus replicated and caused severe lesions not only in respiratory tissues but also in multiple extra-respiratory tissues, including brain, liver, pancreas, spleen, lymph nodes, and adrenal gland. Sequence analyses demonstrated that the well-known mammalian adaptation substitution D701N was positively selected in almost all ferrets. In the in vitro experiments, no other known viral phenotypic properties associated with mammalian adaptation or increased pathogenicity were identified. The lack of transmission via the air and the absence of mammalian adaptation markers suggest that the public health risk of this virus is low. The high pathogenicity of this virus in ferrets could not be explained by the known mammalian pathogenicity factors and should be further studied. IMPORTANCE Avian influenza A/H5 viruses can cross the species barrier and infect humans. These infections can have a fatal outcome, but fortunately these influenza A/H5 viruses do not spread between humans. However, the extensive circulation and reassortment of A/H5N6 viruses in poultry and wild birds warrant risk assessments of circulating strains. Here an in-depth characterization of the properties of an avian A/H5N6 influenza virus isolated from a black-headed gull in the Netherlands was performed in vitro and in vivo, in ferrets. The virus was not transmissible via the air but caused severe disease and spread to extra-respiratory organs. Apart from the detection in ferrets of a mutation that increased virus replication, no other mammalian adaptation phenotypes were identified. Our results suggest that the risk of this avian A/H5N6 virus for public health is low. The underlying reasons for the high pathogenicity of this virus are unexplained and should be further studied.
Assuntos
Virus da Influenza A Subtipo H5N1 , Vírus da Influenza A Subtipo H5N2 , Vírus da Influenza A , Influenza Aviária , Humanos , Animais , Furões , Virus da Influenza A Subtipo H5N1/genética , Vírus da Influenza A Subtipo H5N2/genética , Vírus da Influenza A/genética , Aves DomésticasRESUMO
SARS-CoV-2 emerged in late 2019 and caused a pandemic, whereas the closely related SARS-CoV was contained rapidly in 2003. Here, an experimental set-up is used to study transmission of SARS-CoV and SARS-CoV-2 through the air between ferrets over more than a meter distance. Both viruses cause a robust productive respiratory tract infection resulting in transmission of SARS-CoV-2 to two of four indirect recipient ferrets and SARS-CoV to all four. A control pandemic A/H1N1 influenza virus also transmits efficiently. Serological assays confirm all virus transmission events. Although the experiments do not discriminate between transmission via small aerosols, large droplets and fomites, these results demonstrate that SARS-CoV and SARS-CoV-2 can remain infectious while traveling through the air. Efficient virus transmission between ferrets is in agreement with frequent SARS-CoV-2 outbreaks in mink farms. Although the evidence for virus transmission via the air between humans under natural conditions is absent or weak for SARS-CoV and SARS-CoV-2, ferrets may represent a sensitive model to study interventions aimed at preventing virus transmission.
Assuntos
Microbiologia do Ar , COVID-19/transmissão , Furões/virologia , SARS-CoV-2 , Síndrome Respiratória Aguda Grave/transmissão , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave , Aerossóis , Substituição de Aminoácidos , Pelo Animal/virologia , Animais , COVID-19/virologia , Modelos Animais de Doenças , Feminino , Fômites/virologia , Vírus da Influenza A Subtipo H1N1 , Modelos Biológicos , Infecções por Orthomyxoviridae/transmissão , Polimorfismo de Nucleotídeo Único , SARS-CoV-2/genética , Síndrome Respiratória Aguda Grave/virologia , Fatores de Tempo , Carga Viral , Zoonoses Virais/transmissão , Zoonoses Virais/virologia , Eliminação de Partículas ViraisRESUMO
Human influenza A viruses are known to be transmitted via the air from person to person. It is unknown from which anatomical site of the respiratory tract influenza A virus transmission occurs. Here, pairs of genetically tagged and untagged influenza A/H1N1, A/H3N2 and A/H5N1 viruses that are transmissible via the air are used to co-infect donor ferrets via the intranasal and intratracheal routes to cause an upper and lower respiratory tract infection, respectively. In all transmission cases, we observe that the viruses in the recipient ferrets are of the same genotype as the viruses inoculated intranasally, demonstrating that they are expelled from the upper respiratory tract of ferrets rather than from trachea or the lower airways. Moreover, influenza A viruses that are transmissible via the air preferentially infect ferret and human nasal respiratory epithelium. These results indicate that virus replication in the upper respiratory tract, the nasal respiratory epithelium in particular, of donors is a driver for transmission of influenza A viruses via the air.
Assuntos
Furões/virologia , Vírus da Influenza A/fisiologia , Mucosa Nasal/virologia , Infecções por Orthomyxoviridae/transmissão , Ar , Animais , Cães , Feminino , Humanos , Vírus da Influenza A/genética , Vírus da Influenza A/patogenicidade , Células Madin Darby de Rim Canino , Infecções por Orthomyxoviridae/veterinária , Tropismo ViralRESUMO
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMO
In 2014, an outbreak of avian A/H10N7 influenza virus occurred among seals along North-European coastal waters, significantly impacting seal populations. Here, we examine the cross-species transmission and mammalian adaptation of this influenza A virus, revealing changes in the hemagglutinin surface protein that increase stability and receptor binding. The seal A/H10N7 virus was aerosol or respiratory droplet transmissible between ferrets. Compared with avian H10 hemagglutinin, seal H10 hemagglutinin showed stronger binding to the human-type sialic acid receptor, with preferential binding to α2,6-linked sialic acids on long extended branches. In X-ray structures, changes in the 220-loop of the receptor-binding pocket caused similar interactions with human receptor as seen for pandemic strains. Two substitutions made seal H10 hemagglutinin more stable than avian H10 hemagglutinin and similar to human hemagglutinin. Consequently, identification of avian-origin influenza viruses across mammals appears critical to detect influenza A viruses posing a major threat to humans and other mammals.
Assuntos
Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Infecções por Orthomyxoviridae/diagnóstico , Infecções por Orthomyxoviridae/transmissão , Aerossóis , Animais , Sítios de Ligação , Aves/virologia , Furões/virologia , Humanos , Vírus da Influenza A Subtipo H10N7 , Vírus da Influenza A/metabolismo , Influenza Aviária/virologia , Mamíferos , Fusão de Membrana , Modelos Moleculares , Infecções por Orthomyxoviridae/virologia , Polissacarídeos , Ácidos Siálicos/metabolismoRESUMO
In late December 2019, a cluster of cases of pneumonia of unknown etiology were reported linked to a market in Wuhan, China1. The causative agent was identified as the species Severe acute respiratory syndrome-related coronavirus and was named SARS-CoV-2 (ref. 2). By 16 April the virus had spread to 185 different countries, infected over 2,000,000 people and resulted in over 130,000 deaths3. In the Netherlands, the first case of SARS-CoV-2 was notified on 27 February. The outbreak started with several different introductory events from Italy, Austria, Germany and France followed by local amplification in, and later also outside, the south of the Netherlands. The combination of near to real-time whole-genome sequence analysis and epidemiology resulted in reliable assessments of the extent of SARS-CoV-2 transmission in the community, facilitating early decision-making to control local transmission of SARS-CoV-2 in the Netherlands. We demonstrate how these data were generated and analyzed, and how SARS-CoV-2 whole-genome sequencing, in combination with epidemiological data, was used to inform public health decision-making in the Netherlands.
Assuntos
Betacoronavirus/genética , Infecções por Coronavirus/genética , Genoma Viral/genética , Pandemias , Pneumonia Viral/genética , Betacoronavirus/patogenicidade , COVID-19 , Tomada de Decisão Clínica , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Humanos , Países Baixos/epidemiologia , Pneumonia Viral/epidemiologia , Pneumonia Viral/patologia , Pneumonia Viral/virologia , Saúde Pública , SARS-CoV-2 , Sequenciamento Completo do GenomaRESUMO
BACKGROUND: 10 days after the first reported case of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the Netherlands (on Feb 27, 2020), 55 (4%) of 1497 health-care workers in nine hospitals located in the south of the Netherlands had tested positive for SARS-CoV-2 RNA. We aimed to gain insight in possible sources of infection in health-care workers. METHODS: We did a cross-sectional study at three of the nine hospitals located in the south of the Netherlands. We screened health-care workers at the participating hospitals for SARS-CoV-2 infection, based on clinical symptoms (fever or mild respiratory symptoms) in the 10 days before screening. We obtained epidemiological data through structured interviews with health-care workers and combined this information with data from whole-genome sequencing of SARS-CoV-2 in clinical samples taken from health-care workers and patients. We did an in-depth analysis of sources and modes of transmission of SARS-CoV-2 in health-care workers and patients. FINDINGS: Between March 2 and March 12, 2020, 1796 (15%) of 12â022 health-care workers were screened, of whom 96 (5%) tested positive for SARS-CoV-2. We obtained complete and near-complete genome sequences from 50 health-care workers and ten patients. Most sequences were grouped in three clusters, with two clusters showing local circulation within the region. The noted patterns were consistent with multiple introductions into the hospitals through community-acquired infections and local amplification in the community. INTERPRETATION: Although direct transmission in the hospitals cannot be ruled out, our data do not support widespread nosocomial transmission as the source of infection in patients or health-care workers. FUNDING: EU Horizon 2020 (RECoVer, VEO, and the European Joint Programme One Health METASTAVA), and the National Institute of Allergy and Infectious Diseases, National Institutes of Health.
Assuntos
Betacoronavirus/genética , Infecções Comunitárias Adquiridas/epidemiologia , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/transmissão , Infecção Hospitalar/epidemiologia , Pessoal de Saúde , Pneumonia Viral/epidemiologia , Pneumonia Viral/transmissão , Adulto , Idoso , COVID-19 , Infecções Comunitárias Adquiridas/virologia , Infecções por Coronavirus/virologia , Infecção Hospitalar/virologia , Estudos Transversais , Feminino , Variação Genética , Hospitais de Ensino , Humanos , Masculino , Programas de Rastreamento/métodos , Pessoa de Meia-Idade , Países Baixos/epidemiologia , Pandemias , Pneumonia Viral/virologia , SARS-CoV-2 , Sequenciamento Completo do Genoma , Adulto JovemRESUMO
Influenza A virus surveillance studies of wild bird populations are essential to improving our understanding of the role of wild birds in the ecology of low-pathogenic avian influenza viruses and their potential contribution to the spread of H5N1 highly pathogenic avian influenza viruses. Whereas the primary results of such surveillance programs have been communicated extensively, practical considerations and technical implementation options generally receive little attention. In the present study, the data obtained from 39,490 samples were used to compare the impacts of variables such as the sampling procedure, storage and transport conditions, and the choice of molecular and classical diagnostic tests on the outcome of the results. Molecular diagnostic tests allowed estimation of the virus load in samples, which has implications for the ability to isolate virus. Virus isolation in embryonated eggs was more sensitive than virus isolation in cell cultures. Storage and transport conditions had less of an impact on diagnostics by the use of molecular tests than by the use of classical approaches. These findings indicate that molecular diagnostic tests are more sensitive and more reliable than classical tests. In addition, molecular diagnostic tests facilitated analyses in real time and allowed the discrimination of H5 influenza viruses with low and high pathogenicities without the need for virus isolation. Critical assessment of the methods used in large surveillance studies like this will facilitate comparison of the results between studies. Moreover, the lessons learned from current large-scale influenza A virus surveillance activities could be valuable for other pathogen surveillance programs in the future.
Assuntos
Vírus da Influenza A/isolamento & purificação , Influenza Aviária/diagnóstico , Influenza Aviária/virologia , Técnicas de Diagnóstico Molecular/métodos , Animais , Aves , Linhagem Celular , Embrião de Galinha , Vírus da Influenza A/genética , Influenza Aviária/epidemiologia , Sensibilidade e Especificidade , Manejo de Espécimes/métodos , Cultura de Vírus/métodosRESUMO
Although extensive data exist on avian influenza in wild birds in North America, limited information is available from elsewhere, including Europe. Here, molecular diagnostic tools were employed for high-throughput surveillance of migratory birds, as an alternative to classical labor-intensive methods of virus isolation in eggs. This study included 36,809 samples from 323 bird species belonging to 18 orders, of which only 25 species of three orders were positive for influenza A virus. Information on species, locations, and timing is provided for all samples tested. Seven previously unknown host species for avian influenza virus were identified: barnacle goose, bean goose, brent goose, pink-footed goose, bewick's swan, common gull, and guillemot. Dabbling ducks were more frequently infected than other ducks and Anseriformes; this distinction was probably related to bird behavior rather than population sizes. Waders did not appear to play a role in the epidemiology of avian influenza in Europe, in contrast to the Americas. The high virus prevalence in ducks in Europe in spring as compared with North America could explain the differences in virus-host ecology between these continents. Most influenza A virus subtypes were detected in ducks, but H13 and H16 subtypes were detected primarily in gulls. Viruses of subtype H6 were more promiscuous in host range than other subtypes. Temporal and spatial variation in influenza virus prevalence in wild birds was observed, with influenza A virus prevalence varying by sampling location; this is probably related to migration patterns from northeast to southwest and a higher prevalence farther north along the flyways. We discuss the ecology and epidemiology of avian influenza A virus in wild birds in relation to host ecology and compare our results with published studies. These data are useful for designing new surveillance programs and are particularly relevant due to increased interest in avian influenza in wild birds.