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PURPOSE: Benefit from convalescent plasma therapy for coronavirus disease 2019 (COVID-19) has been inconsistent in randomized clinical trials (RCTs) involving critically ill patients. As COVID-19 patients are immunologically heterogeneous, we hypothesized that immunologically similar COVID-19 subphenotypes may differ in their treatment responses to convalescent plasma and explain inconsistent findings between RCTs . METHODS: We tested this hypothesis in a substudy involving 1239 patients, by measuring 26 biomarkers (cytokines, chemokines, endothelial biomarkers) within the randomized, embedded, multifactorial, adaptive platform trial for community-acquired pneumonia (REMAP-CAP) that assigned 2097 critically ill COVID-19 patients to either high-titer convalescent plasma or usual care. Primary outcome was organ support free days at 21 days (OSFD-21) . RESULTS: Unsupervised analyses identified three subphenotypes/endotypes. In contrast to the more homogeneous subphenotype-2 (N = 128 patients, 10.3%; with elevated type i and type ii effector immune responses) and subphenotype-3 (N = 241, 19.5%; with exaggerated inflammation), the subphenotype-1 had variable biomarker patterns (N = 870 patients, 70.2%). Subphenotypes-2, and -3 had worse outcomes, and subphenotype-1 had better outcomes with convalescent plasma therapy compared with usual care (median (IQR). OSFD-21 in convalescent plasma vs usual care was 0 (- 1, 21) vs 10 (- 1, to 21) in subphenotype-2; 1.5 (- 1, 21) vs 12 (- 1, to 21) in suphenotype-3, and 0 (- 1, 21) vs 0 (- 1, to 21) in subphenotype-1 (test for between-subphenotype differences in treatment effects p = 0.008). CONCLUSIONS: We reported three COVID-19 subphenotypes, among critically ill adults, with differential treatment effects to ABO-compatible convalescent plasma therapy. Differences in subphenotype prevalence between RCT populations probably explain inconsistent results with COVID-19 immunotherapies.
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COVID-19 , Adulto , Humanos , COVID-19/terapia , Estado Terminal/terapia , Biomarcadores , Citocinas , Resultado do Tratamento , Soroterapia para COVID-19RESUMO
Measles is a highly contagious viral illness that continues to cause significant mortality among young children worldwide despite the availability of a safe and effective vaccine. During the first half of 2019, over 182 countries reported more than 300,000 measles cases; greater than double the number from the same period in 2018. Timely recognition and laboratory confirmation of infected individuals as well as appropriate infection prevention measures are crucial to avert further transmission. This review highlights the importance of early recognition of the signs and symptoms of measles and provides details on the laboratory methods commonly employed to confirm cases, investigate outbreaks and characterize the virus. It's critical that clinicians, laboratorians and public health administrations work together to rapidly identify, confirm and contain the spread of measles globally.
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Técnicas de Laboratório Clínico/métodos , Sarampo/diagnóstico , Sarampo/prevenção & controle , Criança , Surtos de Doenças/prevenção & controle , Humanos , Sarampo/epidemiologia , Sarampo/transmissão , Vacina contra Sarampo , Vírus do Sarampo/classificação , VacinaçãoRESUMO
Unfortunately, one of the affiliations of author "A. E. Gorbalenya" was missed in original version. The affiliation is updated here.
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Enteroviruses (EVs) and rhinoviruses (RVs) are significant pathogens of humans and are the subject of intensive clinical and epidemiological research and public health measures, notably in the eradication of poliovirus and in the investigation and control of emerging pathogenic EV types worldwide. EVs and RVs are highly diverse in their antigenic properties, tissue tropism, disease associations and evolutionary relationships, but the latter often conflict with previously developed biologically defined terms, such as "coxsackieviruses", "polioviruses" and "echoviruses", which were used before their genetic interrelationships were understood. This has created widespread formatting problems and inconsistencies in the nomenclature for EV and RV types and species in the literature and public databases. As members of the International Committee for Taxonomy of Viruses (ICTV) Picornaviridae Study Group, we describe the correct use of taxon names for these viruses and have produced a series of recommendations for the nomenclature of EV and RV types and their abbreviations. We believe their adoption will promote greater clarity and consistency in the terminology used in the scientific and medical literature. The recommendations will additionally provide a useful reference guide for journals, other publications and public databases seeking to use standardised terms for the growing multitude of enteroviruses and rhinoviruses described worldwide.
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Enterovirus/classificação , Rhinovirus/classificação , Terminologia como Assunto , HumanosRESUMO
Polymerase chain reaction (PCR) detection has become the gold standard for diagnosis and typing of enterovirus (EV) and human parechovirus (HPeV) infections. Its effectiveness depends critically on using the appropriate sample types and high assay sensitivity as viral loads in cerebrospinal fluid samples from meningitis and sepsis clinical presentation can be extremely low. This study evaluated the sensitivity and specificity of currently used commercial and in-house diagnostic and typing assays. Accurately quantified RNA transcript controls were distributed to 27 diagnostic and 12 reference laboratories in 17 European countries for blinded testing. Transcripts represented the four human EV species (EV-A71, echovirus 30, coxsackie A virus 21, and EV-D68), HPeV3, and specificity controls. Reported results from 48 in-house and 15 commercial assays showed 98% detection frequencies of high copy (1000 RNA copies/5 µL) transcripts. In-house assays showed significantly greater detection frequencies of the low copy (10 copies/5 µL) EV and HPeV transcripts (81% and 86%, respectively) compared with commercial assays (56%, 50%; P = 7 × 10-5 ). EV-specific PCRs showed low cross-reactivity with human rhinovirus C (3 of 42 tests) and infrequent positivity in the negative control (2 of 63 tests). Most or all high copy EV and HPeV controls were successfully typed (88%, 100%) by reference laboratories, but showed reduced effectiveness for low copy controls (41%, 67%). Stabilized RNA transcripts provide an effective, logistically simple and inexpensive reagent for evaluation of diagnostic assay performance. The study provides reassurance of the performance of the many in-house assay formats used across Europe. However, it identified often substantially reduced sensitivities of commercial assays often used as point-of-care tests.
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Infecções por Enterovirus/diagnóstico , Enterovirus/classificação , Parechovirus/classificação , Infecções por Picornaviridae/diagnóstico , RNA Viral/genética , Infecções por Enterovirus/virologia , Europa (Continente) , Dosagem de Genes , Humanos , Meningite Viral/diagnóstico , Tipagem Molecular , Infecções por Picornaviridae/virologia , Kit de Reagentes para Diagnóstico , Reação em Cadeia da Polimerase em Tempo Real , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
An aggregation of moxifloxacin-resistant Clostridium difficile ribotype 231 (RT231) isolates was first identified in the county of Stockholm in 2008, and by the end of 2015 isolates of RT231 had spread to 13 of 21 Swedish counties. We investigated the epidemiology of C. difficile RT231 in Sweden between 2006 and 2015 using whole genome sequencing (WGS) and evaluated whether its emergence could be associated with extended moxifloxacin use. We performed WGS and phylogenetic analysis of 51 C. difficile RT231 strains isolated in Sweden over a 10-year period. We also calculated the county-specific prescription rates for moxifloxacin between 2005 and 2015. Using WGS and detailed single nucleotide polymorphism analysis, we demonstrated three divergent sublineages of moxifloxacin-resistant C. difficile RT231 in Sweden from 2008 to 2015. A set of closely related RT231 was identified in hospitals located in the counties of Stockholm and Uppsala in 2008. Another set of RT231 isolates was found in four different counties in the Uppsala-Örebro Health Care Region. A gradual drop in moxifloxacin use in the county of Stockholm coincided with a reduction of RT231 in the area. However, RT231 continued to be frequent in surrounding counties including Uppsala, a county that also had the highest moxifloxacin prescription rates. We demonstrated frequent transmission of C. difficile RT231 within and between counties, indicating the importance of careful monitoring of hospitalized individuals infected with moxifloxacin-resistant C. difficile as well as the need for a strict moxifloxacin prescription policy.
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Acute viral hepatitis affects all ages worldwide. Hepatitis E virus (HEV) is increasingly recognized as a major cause of acute hepatitis in Europe. Because knowledge of its characteristics is limited, we conducted a retrospective study to outline demographic and clinical features of acute HEV in comparison to hepatitis A, B and C in Lothian over 28 months (January 2012 to April 2014). A total of 3204 blood samples from patients with suspected acute hepatitis were screened for hepatitis A, B and C virus; 913 of these samples were also screened for HEV. Demographic and clinical information on patients with positive samples was gathered from electronic patient records. Confirmed HEV samples were genotyped. Of 82 patients with confirmed viral hepatitis, 48 (59%) had acute HEV. These patients were older than those infected by hepatitis A, B or C viruses, were more often male and typically presented with jaundice, nausea, vomiting and/or malaise. Most HEV cases (70%) had eaten pork or game meat in the few months before infection, and 14 HEV patients (29%) had a recent history of foreign travel. The majority of samples were HEV genotype 3 (27/30, 90%); three were genotype 1. Acute HEV infection is currently the predominant cause of acute viral hepatitis in Lothian and presents clinically in older men. Most of these infections are autochthonous, and further studies confirming the sources of infection (i.e. food or blood transfusion) are required.
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Bacteriemia/epidemiologia , Técnicas Bacteriológicas/métodos , Infecções por Campylobacter/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Suécia/epidemiologia , Adulto JovemRESUMO
Parvovirus B19 (B19V) infections are a common but under-investigated and under-reported cause of intrauterine infections. An increased number of acute B19V infections was identified in the Edinburgh area in 2012-2013, with 123 infections diagnosed in 33 pregnant women, 76 non-pregnant women and 14 men. All except one pregnant woman were asymptomatic. An overall infection rate of 18% was measured in pregnant women who were tested following B19V exposure (26/141). Furthermore, a 7% seroconversion rate was recorded in non-immune pregnant women who were re-tested after exposure (7/104). A high fetal loss rate (25%; 3/12) was observed in those who had acute B19V infection in early pregnancy (<11 weeks) whereas all pregnancies progressed to term in those where acute infection occurred after a gestational age of 12 weeks. These results suggest that more efforts should be targeted to investigate suspected B19V infections in early pregnancy during epidemic seasons.
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Infecções por Parvoviridae/epidemiologia , Infecções por Parvoviridae/virologia , Parvovirus B19 Humano/isolamento & purificação , Aborto Séptico/epidemiologia , Adolescente , Adulto , Doenças Assintomáticas/epidemiologia , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Infecções por Parvoviridae/complicações , Gravidez , Escócia/epidemiologia , Adulto JovemAssuntos
Efeitos Psicossociais da Doença , Vírus da Influenza B/isolamento & purificação , Influenza Humana/diagnóstico , Adolescente , Adulto , Fatores Etários , Idoso , Antivirais/uso terapêutico , Criança , Pré-Escolar , Feminino , Custos de Cuidados de Saúde/estatística & dados numéricos , Hospitalização/estatística & dados numéricos , Humanos , Incidência , Vírus da Influenza B/genética , Influenza Humana/tratamento farmacológico , Influenza Humana/economia , Influenza Humana/epidemiologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Estudos Retrospectivos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Escócia/epidemiologia , Vigilância de Evento Sentinela , Análise de Sequência , Índice de Gravidade de Doença , Resultado do Tratamento , Adulto JovemRESUMO
In January to February 2014, 16 hand, foot and mouth disease (HFMD) cases were identified in Edinburgh, United Kingdom. All presented with atypical features, with most (n=13) resembling eczema herpeticum or chickenpox. Coxsackievirus A6 (CV-A6) was identified in all the typed cases (n=11). As atypical forms of HFMD associated with CV-A6 are likely to emerge throughout Europe, clinicians should be alert to unusual clinical presentations of HFMD and virologists aware of effective diagnostic testing and enterovirus typing methods.
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Infecções por Coxsackievirus/complicações , Enterovirus Humano A/genética , Doença de Mão, Pé e Boca/complicações , Doença de Mão, Pé e Boca/virologia , Adulto , Varicela/etiologia , Pré-Escolar , Infecções por Coxsackievirus/epidemiologia , Infecções por Coxsackievirus/virologia , Diagnóstico Diferencial , Surtos de Doenças , Enterovirus Humano A/isolamento & purificação , Feminino , Doença de Mão, Pé e Boca/epidemiologia , Humanos , Lactente , Erupção Variceliforme de Kaposi/etiologia , Masculino , Pessoa de Meia-Idade , RNA Viral/genética , Reação em Cadeia da Polimerase em Tempo Real , Estudos Retrospectivos , Vigilância de Evento Sentinela , Análise de Sequência de DNA , Reino Unido/epidemiologiaRESUMO
Human enteroviruses (EV) and parechoviruses (HPeV) within the family Picornaviridae are the most common causes of viral central nervous system (CNS)-associated infections including meningitis and neonatal sepsis-like disease. The frequencies of EV and HPeV types identified in clinical specimens collected in Scotland over an eight-year period were compared to those identified in sewage surveillance established in Edinburgh. Of the 35 different EV types belonging to four EV species (A to D) and the four HPeV types detected in this study, HPeV3 was identified as the most prevalent picornavirus in cerebrospinal fluid samples, followed by species B EV. Interestingly, over half of EV and all HPeV CNS-associated infections were observed in young infants (younger than three months). Detection of species A EV including coxsackievirus A6 and EV71 in clinical samples and sewage indicates that these viruses are already widely circulating in Scotland. Furthermore, species C EV were frequently identified EV in sewage screening but they were not present in any of 606 EV-positive clinical samples studied, indicating their likely lower pathogenicity. Picornavirus surveillance is important not only for monitoring the changing epidemiology of these infections but also for the rapid identification of spread of emerging EV and/or HPeV types.
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Infecções do Sistema Nervoso Central/epidemiologia , Líquido Cefalorraquidiano/virologia , Enterovirus/isolamento & purificação , Parechovirus/isolamento & purificação , Infecções por Picornaviridae/epidemiologia , Sepse/virologia , Infecções do Sistema Nervoso Central/líquido cefalorraquidiano , Infecções do Sistema Nervoso Central/virologia , Enterovirus/genética , Fezes/virologia , Humanos , Parechovirus/genética , Filogenia , Infecções por Picornaviridae/líquido cefalorraquidiano , Infecções por Picornaviridae/virologia , Prevalência , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Escócia , Vigilância de Evento Sentinela , Sepse/líquido cefalorraquidiano , Sepse/epidemiologia , Análise de Sequência de DNA , Sorotipagem , Esgotos , Manejo de Espécimes , Reino Unido/epidemiologiaRESUMO
Human rhinoviruses (HRVs) can be divided into three species; HRV-A to HRV-C. Up to 148 different HRV (sero)types have been identified to date. Because of sequence similarity between 5'-NCR of HRVs and enteroviruses (EVs), it is problematic to design EV-specific RT-PCR assays. The aims of this study were to assess the rate of false-detection of different rhinoviruses by EV RT-PCR, and to evaluate the diagnostic and clinical significance of such cross-reactivity. In vitro RNA transcripts of HRV A-C created from cDNA templates were quantified spectrophotometrically. Six hundred twenty-one stool samples screened as part of routine diagnostic for EV, 17 EV-positive stool samples referred for typing, 288 stool samples submitted for gastroenteritis investigations, and 1,500 CSF samples were included in the study. EV-specific RT-PCR detected RNA transcripts of HRV-A1b, HRV-B14, and HRV-Crpat18 but with 10-1,000 reduced sensitivity compared to EV transcripts. Screening fecal samples by EV RT-PCR identified 13 positive samples identified subsequently as rhinoviruses; a further 26 HRV-positive samples were identified by nested HRV RT-PCR. All individuals were hospitalized and presented mostly with diarrhea. A total of 26 HRV types were identified (HRV-A: 46%; HRV-B: 13%; HRV-C: 41%). Results confirm that EV-specific RT-PCR can detect HRVs, and at a practical level, identify potential problems of interpretation if fecal samples are used for surrogate screening in cases of suspected viral meningitis. High detection frequencies (10%) and viral loads in stool samples provide evidence for enteric replication of HRV, and its association with enteric disease requires further etiological studies.
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Infecções por Picornaviridae/diagnóstico , Infecções por Picornaviridae/virologia , Rhinovirus/classificação , Rhinovirus/isolamento & purificação , Carga Viral , Eliminação de Partículas Virais , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Diagnóstico Diferencial , Enterovirus/genética , Infecções por Enterovirus/diagnóstico , Infecções por Enterovirus/virologia , Fezes/virologia , Humanos , Lactente , Recém-Nascido , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Rhinovirus/genética , Sensibilidade e EspecificidadeRESUMO
Enterovirus 71 (EV71) is responsible for frequent large-scale outbreaks of hand, foot, and mouth disease worldwide and represent a major etiological agent of severe, sometimes fatal neurological disease. EV71 variants have been classified into three genogroups (GgA, GgB, and GgC), and the latter two are further subdivided into subgenogroups B1 to B5 and C1 to C5. To investigate the dual roles of recombination and evolution in the epidemiology and transmission of EV71 worldwide, we performed a large-scale genetic analysis of isolates (n = 308) collected from 19 countries worldwide over a 40-year period. A series of recombination events occurred over this period, which have been identified through incongruities in sequence grouping between the VP1 and 3Dpol regions. Eleven 3Dpol clades were identified, each specific to EV71 and associated with specific subgenogroups but interspersed phylogenetically with clades of coxsackievirus A16 and other EV species A serotypes. The likelihood of recombination increased with VP1 sequence divergence; mean half-lives for EV71 recombinant forms (RFs) of 6 and 9 years for GgB and GgC overlapped with those observed for the EV-B serotypes, echovirus 9 (E9), E30, and E11, respectively (1.3 to 9.8 years). Furthermore, within genogroups, sporadic recombination events occurred, such as the linkage of two B4 variants to RF-W instead of RF-A and of two C4 variants to RF-H. Intriguingly, recombination events occurred as a founding event of most subgenogroups immediately preceding their lineage expansion and global emergence. The possibility that recombination contributed to their subsequent spread through improved fitness requires further biological and immunological characterization.
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Enterovirus Humano A/classificação , Enterovirus Humano A/genética , Infecções por Enterovirus/virologia , Evolução Molecular , Filogenia , Recombinação Genética , Enterovirus Humano A/isolamento & purificação , Humanos , Dados de Sequência Molecular , Proteínas Virais/genéticaRESUMO
BACKGROUND: The most common acute infections occur in the respiratory tract. Recent discoveries of several novel viruses have markedly increased the repertoire of agents understood to cause presentations of acute respiratory disease. OBJECTIVES: Further understanding is needed of the relative importance of newly discovered pathogens in the clinical setting to provide clinicians with an indication of appropriate diagnostic and therapeutic targets. To address this, quantification of the disease burden of respiratory viruses in hospitalized patients was undertaken. STUDY DESIGN: Disease burden caused by respiratory viruses in hospitalized patients was quantified using the World Health Organization endorsed DALY model. Diagnostic testing results from samples collected over three years for adenovirus (AdV), influenzas A and B, parainfluenza viruses 1, 2 and 3 (PIV-1, -2 and -3), respiratory syncytial virus (HRSV), and previously published retrospective screening for human metapneumovirus, rhinoviruses, and four respiratory coronaviruses were applied to the DALY model. Disability weights were calculated per 1000 hospitalized patients in age banded groups. RESULTS: Strikingly different disease burden profiles were observed in children and adults. Adenoviruses were among the leading cause of respiratory presentations in children but not adults. HRSV and influenza A were consistently one of the greatest causes of disease regardless of sampled population. Rhinoviruses and PIV-3 were significant pathogens in all groups except those aged 16-64 years. In immunocompromised patients rhinoviruses were the leading viral cause of disease. CONCLUSIONS: These analyses provide a framework which can be used to identify where finite resources should be directed in respiratory therapeutics and vaccine development.
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Infecções Respiratórias , Carga Viral , Viroses , Infecções por Adenoviridae/diagnóstico , Infecções por Adenoviridae/virologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/virologia , Efeitos Psicossociais da Doença , Feminino , Hospitalização , Humanos , Lactente , Influenza Humana/diagnóstico , Influenza Humana/virologia , Masculino , Pessoa de Meia-Idade , Infecções por Paramyxoviridae/diagnóstico , Infecções por Paramyxoviridae/virologia , Infecções por Picornaviridae/diagnóstico , Infecções por Picornaviridae/virologia , Anos de Vida Ajustados por Qualidade de Vida , Infecções por Vírus Respiratório Sincicial/diagnóstico , Infecções por Vírus Respiratório Sincicial/virologia , Infecções Respiratórias/diagnóstico , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/virologia , Viroses/diagnóstico , Viroses/epidemiologia , Viroses/virologiaRESUMO
The relationship between virus evolution and recombination in species B human enteroviruses was investigated through large-scale genetic analysis of echovirus type 9 (E9) and E11 isolates (n = 85 and 116) from 16 European, African, and Asian countries between 1995 and 2008. Cluster 1 E9 isolates and genotype D5 and A E11 isolates showed evidence of frequent recombination between the VP1 and 3Dpol regions, the latter falling into 23 (E9) and 43 (E11) clades interspersed phylogenetically with 46 3Dpol clades of E30 and with those of other species B serotypes. Remarkably, only 2 of the 112 3Dpol clades were shared by more than one serotype (E11 and E30), demonstrating an extremely large and genetically heterogeneous recombination pool of species B nonstructural-region variants. The likelihood of recombination increased with geographical separation and time, and both were correlated with VP1 divergence, whose substitution rates allowed recombination half-lives of 1.3, 9.8, and 3.1 years, respectively, for E9, E11, and E30 to be calculated. These marked differences in recombination dynamics matched epidemiological patterns of periodic epidemic cycles of 2 to 3 (E9) and 5 to 6 (E30) years and the longer-term endemic pattern of E11 infections. Phylotemporal analysis using a Bayesian Markov chain Monte Carlo method, which placed recombination events within the evolutionary reconstruction of VP1, showed a close relationship with VP1 lineage expansion, with defined recombination events that correlated with their epidemiological periodicity. Whether recombination events contribute directly to changes in transmissibility that drive epidemic behavior or occur stochastically during periodic population bottlenecks is an unresolved issue vital to future understanding of enterovirus molecular epidemiology and pathogenesis.
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Enterovirus Humano B/classificação , Enterovirus Humano B/genética , Infecções por Enterovirus/epidemiologia , Infecções por Enterovirus/virologia , Evolução Molecular , Recombinação Genética , África/epidemiologia , Ásia/epidemiologia , Análise por Conglomerados , Enterovirus Humano B/isolamento & purificação , Europa (Continente)/epidemiologia , Genótipo , Geografia , Humanos , Epidemiologia Molecular , Dados de Sequência Molecular , RNA Viral/genética , Homologia de Sequência , Fatores de TempoRESUMO
To investigate the frequency of oseltamivir resistance in circulating strains of the 2009 influenza A(H1N1) pandemic virus in Scotland, 1,802 samples from 1,608 infected hospitalised patients were screened by the H275Y discriminatory RT-PCR. Among these, we identified 10 patients who developed the H275Y mutation. All of them were immunocompromised and were under treatment or had been treated previously with oseltamivir.
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Farmacorresistência Viral/genética , Hospitalização/tendências , Hospedeiro Imunocomprometido/genética , Vírus da Influenza A Subtipo H1N1/genética , Influenza Humana/genética , Oseltamivir/uso terapêutico , Seguimentos , Humanos , Hospedeiro Imunocomprometido/efeitos dos fármacos , Influenza Humana/tratamento farmacológico , Pandemias , Escócia/epidemiologiaRESUMO
Human parechoviruses (HPeVs) are highly prevalent RNA viruses classified in the family Picornaviridae. Several antigenically distinct types circulate in human populations worldwide, whilst recombination additionally contributes to the genetic heterogeneity of the virus. To investigate factors influencing the likelihood of recombination and to compare its dynamics among types, 154 variants collected from four widely geographically separated referral centres (UK, The Netherlands, Thailand and Brazil) were typed by VP3/VP1 amplification/sequencing with recombination groups assigned by analysis of 3Dpol sequences. HPeV1B and HPeV3 were the most frequently detected types in each referral region, but with marked geographical differences in the frequencies of different recombinant forms (RFs) of types 1B, 5 and 6. HPeV1B showed more frequent recombination than HPeV3, in terms both of evolutionary divergence and of temporal/geographical indicators of population separation. HPeV1 variants showing between 10 and 20% divergence in VP3/VP1 almost invariably fell into different recombination groups, compared with only one-third of similarly divergent HPeV3 variants. Substitution rates calculated by beast in the VP3/VP1 region of HPeV1 and HPeV3 allowed half-lives of the RFs of 4 and 20 years, respectively, to be calculated, estimates fitting closely with their observed lifespans based on population sampling. The variability in recombination dynamics between HPeV1B and HPeV3 offers an intriguing link with their markedly different seasonal patterns of transmission, age distributions of infection and clinical outcomes. Future investigation of the epidemiological and biological opportunities and constraints on intertypic recombination will provide more information about its influence on the longer term evolution and pathogenicity of parechoviruses.
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Parechovirus/genética , Infecções por Picornaviridae/virologia , RNA Viral/genética , Recombinação Genética , Brasil , Análise por Conglomerados , Evolução Molecular , Genótipo , Humanos , Dados de Sequência Molecular , Países Baixos , Filogenia , Polimorfismo Genético , Análise de Sequência de DNA , Homologia de Sequência , Tailândia , Reino UnidoRESUMO
Rhinovirus infections are the most common cause of viral illness in humans, and there is increasing evidence of their etiological role in severe acute respiratory tract infections (ARTIs). Human rhinoviruses (HRVs) are classified into two species, species A and B, which contain over 100 serotypes, and a recently discovered genetically heterogeneous third species (HRV species C). To investigate their diversity and population turnover, screening for the detection and the genetic characterization of HRV variants in diagnostic respiratory samples was performed by using nested primers for the efficient amplification of the VP4-VP2 region of HRV (and enterovirus) species and serotype identification. HRV species A, B, and C variants were detected in 14%, 1.8%, and 6.8%, respectively, of 456 diagnostic respiratory samples from 345 subjects (6 samples also contained enteroviruses), predominantly among children under age 10 years. HRV species A and B variants were remarkably heterogeneous, with 22 and 6 different serotypes, respectively, detected among 73 positive samples. Similarly, by using a pairwise distance threshold of 0.1, species C variants occurring worldwide were provisionally assigned to 47 different types, of which 15 were present among samples from Edinburgh, United Kingdom. There was a rapid turnover of variants, with only 5 of 43 serotypes detected during both sampling periods. By using divergence thresholds and phylogenetic analysis, several species A and C variants could provisionally be assigned to new types. An initial investigation of the clinical differences between rhinovirus species found HRV species C to be nearly twice as frequently associated with ARTIs than other rhinovirus species, which matches the frequencies of detection of respiratory syncytial virus. The study demonstrates the extraordinary genetic diversity of HRVs, their rapid population turnover, and their extensive involvement in childhood respiratory disease.