Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
J Clin Microbiol ; 49(10): 3504-13, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21865418

RESUMEN

Human respiratory syncytial virus (HRSV) is the leading cause of hospitalization of children aged <5 years due to respiratory illness in industrialized countries, and pneumonia is the leading cause of mortality among children aged <5 years worldwide. Although HRSV was first identified in 1956, a preventative vaccine has yet to be developed. Here we report the results of the first study to investigate the circulation and genetic diversity of HRSV in Cambodia among an all-ages population over 5 consecutive years. The incidences of HRSV infection among all-ages outpatient and hospitalized populations were equivalent, at 9.5% and 8.2%, respectively. Infection was most prevalent among children aged <5 years, with bronchiolitis being the most frequently observed clinical syndrome in the same age group. Circulation of HRSV was seasonal, typically coinciding with the rainy season between July and November annually. Strains belonging to HRSV groups A and B were detected with equivalent frequencies; however, we observed a potentially biennial shift in the predominant circulating HRSV genotype. The majority of HRSV group B strains belonged to the recently described BA genotype, with the exception of 10 strains classified as belonging to a novel HRSV group B genotype, SAB4, first reported here.


Asunto(s)
Variación Genética , Infecciones por Virus Sincitial Respiratorio/epidemiología , Infecciones por Virus Sincitial Respiratorio/virología , Virus Sincitial Respiratorio Humano/clasificación , Virus Sincitial Respiratorio Humano/genética , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Cambodia/epidemiología , Niño , Preescolar , Análisis por Conglomerados , Femenino , Genotipo , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Epidemiología Molecular , Datos de Secuencia Molecular , Filogenia , ARN Viral/genética , Virus Sincitial Respiratorio Humano/aislamiento & purificación , Estaciones del Año , Análisis de Secuencia de ADN , Adulto Joven
2.
Anal Chem ; 82(3): 886-91, 2010 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-20041684

RESUMEN

In the present study, we report a novel separation-free method to detect and quantify avian influenza virus A (H5N1) nucleic acid without amplification, based on the alteration of photophysical parameters of quantum dot (QD) probes after hybridization with specific complementary target DNA. The target DNA was quantified in a custom-made portable device by simultaneously measuring lifetime and quenching of the QD probes. QD probes (25-mer) showed a 30% lifetime reduction and 40% fluorescence quenching when hybridized with complementary 25-mer target DNA. In comparison with a conventional QD-based assay, this assay provides a simple quantitation of nucleic acids with a single labeling step.


Asunto(s)
ADN/análisis , Hibridación de Ácido Nucleico/métodos , Sondas de Oligonucleótidos/química , Puntos Cuánticos , ADN Viral/análisis , Subtipo H5N1 del Virus de la Influenza A/genética , Subtipo H5N1 del Virus de la Influenza A/aislamiento & purificación , Cinética
3.
J Clin Microbiol ; 48(1): 295-7, 2010 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19889906
4.
J Med Virol ; 82(10): 1762-72, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20827775

RESUMEN

Acute respiratory infections are a major cause of mortality and morbidity worldwide. Using multiplex PCR/RT-PCR methods for the detection of 18 respiratory viruses, the circulation of those viruses during 3 consecutive dry seasons in Cambodia was described. Among 234 patients who presented with influenza-like illness, 35.5% were positive for at least one virus. Rhinoviruses (43.4%), parainfluenza (31.3%) viruses and coronaviruses (21.7%) were the most frequently detected viruses. Influenza A virus, parainfluenza virus 4 and SARS-coronavirus were not detected during the study period. Ninety apparently healthy individuals were included as controls and 10% of these samples tested positive for one or more respiratory viruses. No significant differences were observed in frequency and in virus copy numbers for rhinovirus detection between symptomatic and asymptomatic groups. This study raises questions about the significance of the detection of some respiratory viruses, especially using highly sensitive methods, given their presence in apparently healthy individuals. The link between the presence of the virus and the origin of the illness is therefore unclear.


Asunto(s)
Enfermedades Respiratorias/epidemiología , Enfermedades Respiratorias/virología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Virología/métodos , Virosis/epidemiología , Virosis/virología , Virus/clasificación , Adolescente , Adulto , Anciano , Cambodia/epidemiología , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Prevalencia , Virus/aislamiento & purificación , Adulto Joven
5.
Emerg Infect Dis ; 15(10): 1641-4, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19861062

RESUMEN

To determine the origin of influenza A virus (H5N1) epizootics in Cambodia, we used maximum-likelihood and Bayesian methods to analyze the genetic sequences of subtype H5N1 strains from Cambodia and neighboring areas. Poultry movements, rather than repeated reintroduction of subtype H5N1 viruses by wild birds, appear to explain virus circulation and perpetuation.


Asunto(s)
Subtipo H5N1 del Virus de la Influenza A/aislamiento & purificación , Gripe Aviar/virología , Gripe Humana/epidemiología , Gripe Humana/virología , Animales , Animales Salvajes , Aves , Cambodia/epidemiología , Brotes de Enfermedades , Humanos , Subtipo H5N1 del Virus de la Influenza A/genética , Gripe Aviar/epidemiología , Epidemiología Molecular , Factores de Tiempo
6.
BMC Infect Dis ; 9: 168, 2009 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-19828051

RESUMEN

BACKGROUND: There is little information about influenza disease among the Cambodian population. To better understand the dynamics of influenza in Cambodia, the Cambodian National Influenza Center (NIC) was established in August 2006. To continuously monitor influenza activity, a hospital based sentinel surveillance system for ILI (influenza like illness) with a weekly reporting and sampling scheme was established in five sites in 2006. In addition, hospital based surveillance of acute lower respiratory infection (ALRI) cases was established in 2 sites. METHODS: The sentinel sites collect weekly epidemiological data on ILI patients fulfilling the case definition, and take naso-pharyngeal specimens from a defined number of cases per week. The samples are tested in the Virology Unit at the Institut Pasteur in Phnom Penh. From each sample viral RNA was extracted and amplified by a multiplex RT-PCR detecting simultaneously influenza A and influenza B virus. Influenza A viruses were then subtyped and analyzed by hemagglutination inhibition assay. Samples collected by the ALRI system were tested with the same approach. RESULTS: From 2006 to 2008, influenza circulation was observed mainly from June to December, with a clear seasonal peak in October shown in the data from 2008. CONCLUSION: Influenza activity in Cambodia occurred during the rainy season, from June to December, and ended before the cool season (extending usually from December to February). Although Cambodia is a tropical country geographically located in the northern hemisphere, influenza activity has a southern hemisphere transmission pattern. Together with the antigenic analysis of the circulating strains, it is now possible to give better influenza vaccination recommendation for Cambodia.


Asunto(s)
Virus de la Influenza A/aislamiento & purificación , Virus de la Influenza B/aislamiento & purificación , Gripe Humana/epidemiología , Vigilancia de Guardia , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Cambodia/epidemiología , Niño , Preescolar , Femenino , Pruebas de Inhibición de Hemaglutinación , Humanos , Lactante , Gripe Humana/virología , Masculino , Persona de Mediana Edad , Prevalencia , ARN Viral/genética , Estaciones del Año , Adulto Joven
7.
Sensors (Basel) ; 9(7): 5590-9, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-22346716

RESUMEN

In the present study we describe sandwich design hybridization probes consisting of magnetic particles (MP) and quantum dots (QD) with target DNA, and their application in the detection of avian influenza virus (H5N1) sequences. Hybridization of 25-, 40-, and 100-mer target DNA with both probes was analyzed and quantified by flow cytometry and fluorescence microscopy on the scale of single particles. The following steps were used in the assay: (i) target selection by MP probes and (ii) target detection by QD probes. Hybridization efficiency between MP conjugated probes and target DNA hybrids was controlled by a fluorescent dye specific for nucleic acids. Fluorescence was detected by flow cytometry to distinguish differences in oligo sequences as short as 25-mer capturing in target DNA and by gel-electrophoresis in the case of QD probes. This report shows that effective manipulation and control of micro- and nanoparticles in hybridization assays is possible.

8.
Emerg Infect Dis ; 14(8): 1303-5, 2008 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-18680663

RESUMEN

To determine potential risk for bird-to-human transmission during influenza A virus (H5N1) outbreaks among backyard poultry in rural Cambodia, we collected environmental specimens. Viral RNA was detected in 27 (35%) of 77 specimens of mud, pond water, water plants, and soil swabs. Our results underscore the need for regular disinfection of poultry areas.


Asunto(s)
Brotes de Enfermedades/veterinaria , Ambiente , Subtipo H5N1 del Virus de la Influenza A/aislamiento & purificación , Gripe Aviar/epidemiología , ARN Viral/aislamiento & purificación , Animales , Cambodia/epidemiología , Pollos , Patos , Plumas/microbiología , Vivienda para Animales , Contaminantes del Suelo , Carga Viral , Microbiología del Agua
9.
J Clin Virol ; 39(3): 164-8, 2007 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-17526430

RESUMEN

BACKGROUND: Between January 2005 and April 2006, six patients of influenza A/H5N1 virus infection were reported in Cambodia, all with fatal outcome. OBJECTIVES: We describe the virological findings of these six H5N1 patients in association with clinical and epidemiologic findings. STUDY DESIGN: Broncho-alveolar lavage, nasopharyngeal, throat and rectal swabs and sera were cultured for virus isolation and viral load quantified in clinical specimens by real-time RT-PCR. We compared sequences obtained from different body sites within the same patient to detect viral quasi-species. RESULTS: H5N1 virus strains isolated in Cambodia belong to genotype Z, clade 1 viruses. H5N1 viruses were isolated from serum and rectal swab specimens in two patients. The haemagglutinin gene sequences of the virus in different body sites did not differ. Amino acid substitutions known to be associated with a change in virus binding were not observed. CONCLUSION: The high frequency of virus isolation from serum and faecal swabs highlights that H5N1 is likely to be a disseminated infection in humans and this has implications for antiviral treatment, biosafety in clinical laboratories and on risks for nosocomial and human-to-human transmission. There were no tissue-specific adaptive mutations in the HA gene from viruses isolated from different organs.


Asunto(s)
Gripe Humana/epidemiología , Adulto , Animales , Sangre/virología , Cambodia/epidemiología , Línea Celular , Niño , Preescolar , Heces/virología , Femenino , Genotipo , Humanos , Subtipo H5N1 del Virus de la Influenza A/clasificación , Subtipo H5N1 del Virus de la Influenza A/genética , Subtipo H5N1 del Virus de la Influenza A/aislamiento & purificación , Gripe Humana/diagnóstico , Gripe Humana/fisiopatología , Gripe Humana/virología , Masculino , ARN Viral/análisis , ARN Viral/aislamiento & purificación , Sistema Respiratorio/virología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Secuencia de ADN , Cultivo de Virus
10.
PLoS One ; 9(10): e110713, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25340711

RESUMEN

BACKGROUND: The Cambodian National Influenza Center (NIC) monitored and characterized circulating influenza strains from 2009 to 2011. METHODOLOGY/PRINCIPAL FINDINGS: Sentinel and study sites collected nasopharyngeal specimens for diagnostic detection, virus isolation, antigenic characterization, sequencing and antiviral susceptibility analysis from patients who fulfilled case definitions for influenza-like illness, acute lower respiratory infections and event-based surveillance. Each year in Cambodia, influenza viruses were detected mainly from June to November, during the rainy season. Antigenic analysis show that A/H1N1pdm09 isolates belonged to the A/California/7/2009-like group. Circulating A/H3N2 strains were A/Brisbane/10/2007-like in 2009 before drifting to A/Perth/16/2009-like in 2010 and 2011. The Cambodian influenza B isolates from 2009 to 2011 all belonged to the B/Victoria lineage represented by the vaccine strains B/Brisbane/60/2008 and B/Malaysia/2506/2004. Sequences of the M2 gene obtained from representative 2009-2011 A/H3N2 and A/H1N1pdm09 strains all contained the S31N mutation associated with adamantanes resistance except for one A/H1N1pdm09 strain isolated in 2011 that lacked this mutation. No reduction in the susceptibility to neuraminidase inhibitors was observed among the influenza viruses circulating from 2009 to 2011. Phylogenetic analysis revealed that A/H3N2 strains clustered each year to a distinct group while most A/H1N1pdm09 isolates belonged to the S203T clade. CONCLUSIONS/SIGNIFICANCE: In Cambodia, from 2009 to 2011, influenza activity occurred throughout the year with peak seasonality during the rainy season from June to November. Seasonal influenza epidemics were due to multiple genetically distinct viruses, even though all of the isolates were antigenically similar to the reference vaccine strains. The drug susceptibility profile of Cambodian influenza strains revealed that neuraminidase inhibitors would be the drug of choice for influenza treatment and chemoprophylaxis in Cambodia, as adamantanes are no longer expected to be effective.


Asunto(s)
Gripe Humana/epidemiología , Gripe Humana/virología , Orthomyxoviridae/fisiología , Animales , Antígenos Virales/inmunología , Cambodia/epidemiología , Perros , Farmacorresistencia Viral , Glicoproteínas Hemaglutininas del Virus de la Influenza/genética , Humanos , Subtipo H1N1 del Virus de la Influenza A/genética , Subtipo H1N1 del Virus de la Influenza A/aislamiento & purificación , Subtipo H3N2 del Virus de la Influenza A/genética , Subtipo H3N2 del Virus de la Influenza A/aislamiento & purificación , Virus de la Influenza B/genética , Virus de la Influenza B/aislamiento & purificación , Vacunas contra la Influenza/inmunología , Gripe Humana/inmunología , Células de Riñón Canino Madin Darby , Orthomyxoviridae/inmunología , Orthomyxoviridae/aislamiento & purificación , Filogenia , Estaciones del Año
11.
J Clin Virol ; 49(3): 211-8, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20855230

RESUMEN

BACKGROUND: Numerous viruses are responsible for respiratory infections; however, both their distribution and genetic diversity, in a limited area and a population subgroup, have been studied only rarely during a sustained period of time. METHODS: A 2-year surveillance program of children presenting with acute respiratory infections (ARIs) was carried out to characterize the viral etiology and to assess whether using gene amplification and sequencing could be a reliable approach to monitor virus introduction and spread in a population subgroup. RESULTS: Using multiplex RT-PCR, 15 different respiratory viruses were detected within the 486 nasopharyngeal positive samples collected among 817 children aged <9-year old who presented with ARI during October 2006 to September 2008. A single virus was detected in 373 patients (45.7%), and two to four viruses in 113 patients (13.8%). The most frequent causative viruses were respiratory syncytial virus (RSV) (24.7%), human bocavirus (24.5%), and human rhinovirus (HRV) (15%). RSV was more prevalent in winter and among young infants. Cases of seasonal influenza A and B viruses were reported mainly in January and August. An increase in adenovirus infection was observed during the spring of the second year of the study. Sequence analyses showed multiple introductions of different virus subtypes and identified a high prevalence of the newly defined HRV-C species. A higher viral incidence was observed during the winter of 2008, which was unusually cold. CONCLUSIONS: This study supports the usefulness of multiplex RT-PCR for virus detection and co-infection, and for implementation of a molecular monitoring system for endemic and epidemic viral respiratory infections.


Asunto(s)
Brotes de Enfermedades , Enfermedades Endémicas , Infecciones del Sistema Respiratorio/epidemiología , Infecciones del Sistema Respiratorio/virología , Virosis/epidemiología , Virosis/virología , Virus/aislamiento & purificación , Niño , Preescolar , China/epidemiología , Humanos , Lactante , Epidemiología Molecular/métodos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Análisis de Secuencia de ADN , Virus/clasificación
12.
J Virol Methods ; 162(1-2): 40-5, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19638288

RESUMEN

A 4-tube multiplex RT-PCR (mRT-PCR), which showed higher sensitivity over conventional methods, was previously developed for the diagnosis of 14 viral pathogens of the respiratory tract. Herein the mRT-PCR was compared to the commercial Luminex mPCR-microsphere flow cytometry assay (Resplex II) which allows the detection of 12 different viruses. Eleven different viruses were identified in 91 nasopharyngeal swabs of children with acute respiratory infection, influenza A (IAV) and B, respiratory syncytial virus (RSV), human rhinovirus (hRhV), human echovirus, parainfluenza viruses (PIV) 1, 2, 3 and 4, human metapneumovirus (hMPV), and human coronavirus NL63. The results of the two techniques showed 53 and 40 positive patients by the Resplex II assay and mRT-PCR, respectively, with a concordance in 35 positive and 33 negative patients (74.7%). Individual RT-PCR tests were performed to control viruses not simultaneously detected by the two multiplex assays. The major virus misdiagnosed by mRT-PCR was IAV whereas the major viruses misdiagnosed by Resplex II were PIV1, 3 and 4. The mRT-PCR remains a simple, rapid, and specific assay for the specific detection of respiratory viruses, and can be easily implemented with standards in clinical laboratories at a low cost.


Asunto(s)
Infecciones por Virus ARN , Virus ARN/aislamiento & purificación , Infecciones del Sistema Respiratorio , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Niño , Preescolar , Citometría de Flujo , Humanos , Lactante , Nasofaringe/virología , Infecciones por Virus ARN/diagnóstico , Infecciones por Virus ARN/virología , Virus ARN/clasificación , Virus ARN/genética , ARN Viral/análisis , ARN Viral/genética , ARN Viral/aislamiento & purificación , Infecciones del Sistema Respiratorio/diagnóstico , Infecciones del Sistema Respiratorio/virología , Sensibilidad y Especificidad , Virus
13.
Emerg Infect Dis ; 12(10): 1542-7, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17176569

RESUMEN

To understand transmission of avian influenza A (H5N1) virus, we conducted a retrospective survey of poultry deaths and a seroepidemiologic investigation in a Cambodian village where a 28-year-old man was infected with H5N1 virus in March 2005. Poultry surveys were conducted within a 1-km radius of the patient's household. Forty-two household flocks were considered likely to have been infected from January through March 2005 because >60% of the flock died, case-fatality ratio was 100%, and both young and mature birds died within 1 to 2 days. Two sick chickens from a property adjacent to the patient's house tested positive for H5N1 on reverse transcription-PCR. Villagers were asked about poultry exposures in the past year and tested for H5N1 antibodies. Despite frequent, direct contact with poultry suspected of having H5N1 virus infection, none of 351 participants from 93 households had neutralizing antibodies to H5N1. H5N1 virus transmission from poultry to humans remains low in this setting.


Asunto(s)
Subtipo H5N1 del Virus de la Influenza A/aislamiento & purificación , Gripe Aviar/transmisión , Gripe Humana/transmisión , Zoonosis/transmisión , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Animales , Aves , Cambodia/epidemiología , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Gripe Aviar/epidemiología , Gripe Aviar/virología , Gripe Humana/epidemiología , Gripe Humana/virología , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Estudios Seroepidemiológicos , Zoonosis/epidemiología , Zoonosis/virología
14.
J Virol ; 78(21): 12030-40, 2004 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-15479842

RESUMEN

A variety of amino acid substitutions in the protease and Gag proteins have been reported to contribute to the development of human immunodeficiency virus type 1 (HIV-1) resistance to protease inhibitors. In the present study, full-length molecular infectious HIV-1 clones were generated by using HIV-1 variants isolated from heavily drug-experienced and therapy-failed AIDS patients. Of six full-length infectious clones generated, four were found to have unique insertions (TGNS, SQVN, AQQA, SRPE, APP, and/or PTAPPA) near the p17/p24 and p1/p6 Gag cleavage sites, in addition to the known resistance-related multiple amino acid substitutions within the protease. The addition of such Gag inserts mostly compromised the replication of wild-type HIV-1, whereas the primary multidrug-resistant HIV infectious clones containing inserts replicated significantly better than those modified to lack the inserts. Western blot analyses revealed that the processing of Gag proteins by wild-type protease was impaired by the presence of the inserts, whereas that by mutant protease was substantially improved. The present study represents the first report clearly demonstrating that the inserts seen in the proximity of the Gag cleavage sites in highly multi-PI resistant HIV-1 variants restore the otherwise compromised enzymatic activity of mutant protease, enabling the multi-PI-resistant HIV-1 variants to remain replication competent.


Asunto(s)
Productos del Gen gag/química , Inhibidores de la Proteasa del VIH/farmacología , VIH-1/efectos de los fármacos , Replicación Viral , Síndrome de Inmunodeficiencia Adquirida/tratamiento farmacológico , Síndrome de Inmunodeficiencia Adquirida/inmunología , Secuencia de Aminoácidos , Secuencia de Bases , Farmacorresistencia Viral Múltiple , Productos del Gen gag/metabolismo , VIH-1/fisiología , Humanos , Datos de Secuencia Molecular , Relación Estructura-Actividad
15.
J Biol Chem ; 277(8): 5952-61, 2002 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-11741936

RESUMEN

Amino acid substitutions in human immunodeficiency virus type 1 (HIV-1) Gag cleavage sites have been identified in HIV-1 isolated from patients with AIDS failing chemotherapy containing protease inhibitors (PIs). However, a number of highly PI-resistant HIV-1 variants lack cleavage site amino acid substitutions. In this study we identified multiple novel amino acid substitutions including L75R, H219Q, V390D/V390A, R409K, and E468K in the Gag protein at non-cleavage sites in common among HIV-1 variants selected against the following four PIs: amprenavir, JE-2147, KNI-272, and UIC-94003. Analyses of replication profiles of various mutant clones including competitive HIV-1 replication assays demonstrated that these mutations were indispensable for HIV-1 replication in the presence of PIs. When some of these mutations were reverted to wild type amino acids, such HIV-1 clones failed to replicate. However, virtually the same Gag cleavage pattern was seen, indicating that the mutations affected Gag protein functions but not their cleavage sensitivity to protease. These data strongly suggest that non-cleavage site amino acid substitutions in the Gag protein recover the reduced replicative fitness of HIV-1 caused by mutations in the viral protease and may open a new avenue for designing PIs that resist the emergence of PI-resistant HIV-1.


Asunto(s)
Productos del Gen gag/metabolismo , Inhibidores de la Proteasa del VIH/farmacología , VIH-1/genética , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Fármacos Anti-VIH/farmacología , Carbamatos , Línea Celular , Clonación Molecular , Farmacorresistencia Microbiana , Furanos , Productos del Gen gag/química , VIH-1/efectos de los fármacos , VIH-1/crecimiento & desarrollo , Humanos , Datos de Secuencia Molecular , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Mapeo Restrictivo , Sulfonamidas/farmacología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA