Prognosis of hospitalized children under 2 years of age with co-detection of influenza A and respiratory syncytial virus at the healthcare facility / Prognóstico de crianças hospitalizadas menores de 2 anos com codetecção de influenza A e vírus sincicial respiratório no local de atendimento

Abstract Objectives: the aim of this study is to evaluate the impact of co-detection of Flu A and RSV using rapid immunochromatographic tests at the point of care, in pediatric patients under 2 years of age in a general hospital. Methods: a retrospective cohort study was conducted to analyze clinical outcomes in hospitalized infants with viral respiratory disease with positive results of rapid immunochromatographic test for RSV and/or Flu-A, from 2013 to 2018. A logistic regression model was adjusted to analyze predictors of orotracheal intubation during hospitalization. Results: we analyzed 220 cases: RSV (192), Flu-A (9), co-detection (19). Lethality rate was 1.8% (2 cases), and 88% (194) were under 1 year of age. Mean time of hospitalizations was higher in patients with co-detection. Variables significantly associated with orotracheal intubation were: younger age in months, comorbidities, RSV and Flu-A co-detection, and bacterial pneumonia during hospitalization. Conclusions: RSV and Flu-Aco-detection was associated with the least favorable clinical prognoses in this study. Rapid test diagnosis may provide important information at the point of care, because molecular panels are not widely accessible in general hospitals. Rapid diagnosis allows timely evaluation and treatment.

Resumo Objetivos: avaliar o impacto da codetecção de Influenza A (FluA) e Vírus Sincicial Respiratório (VSR) por meio de testes imunocromatográficos rápidos em tempo real, em pacientes menores de 2 anos em hospital público e universitário. Métodos: estudo de coorte retrospectivo foi conduzido para analisar os desfechos clínicos de crianças hospitalizadas com doença respiratória viral com resultados positivos do teste rápido imunocromatográfico para VSR e/ou FluA, de 2013 a 2018. Um modelo de regressão logística foi ajustado para analisar preditores de intubação orotraqueal durante a internação. Resultados: foram analisados 220 casos: RSV (192), FluA (9) eco-detecção (19). A letalidade foi de 1,8% (2 casos) e 88% (194) casos em menores de 1 ano. O tempo médio de internação foi maior nos pacientes com codetecção. As variáveis significativamente associadas à intubação orotraqueal foram: menor idade em meses, comorbidades, codetecção de VSR e Flu-A e pneumonia bacteriana durante a internação. Conclusões: codetecção VSR e FluA foi associada a prognósticos clínicos desfavoráveis. O teste rápido fornece informações importantes a beira-leito, pois os painéis moleculares não são amplamente acessíveis em hospitais públicos. O diagnóstico rápido permite a avaliação e tratamento oportunos.

Rapid antigen detection test for respiratory syncytial virus diagnosis as a diagnostic tool / Teste rápido de detecção de antígenos para o diagnóstico do Vírus Sincicial Respiratório como ferramenta de diagnóstico

Abstract Objective: The aim of this study was to evaluate the QuickVue® RSV Test Kit (QUIDEL Corp, CA, USA) as a screening tool for respiratory syncytial virus in children with acute respiratory disease in comparison with the indirect immunofluorescence assay as gold standard. In Brazil, rapid antigen detection tests for respiratory syncytial virus are not routinely utilized as a diagnostic tool, except for the diagnosis of dengue and influenza. Methods: The authors retrospectively analyzed 486 nasopharyngeal aspirate samples from children under age 5 with acute respiratory infection, between December 2013 and August 2014, the samples were analyzed by indirect immunofluorescence assay and QuickVue® RSV Test kit. Samples with discordant results were analyzed by real time PCR and nucleotide sequencing. Results: From 313 positive samples by immunofluorescence assays, 282 (90%) were also positive by the rapid antigen detection test, two were positive only by rapid antigen detection test, 33 were positive only by immunofluorescence assays, and 171 were positive by both methods. The 35 samples with discordant results were analyzed by real time PCR; the two samples positive only by rapid antigen detection test and the five positive only by immunofluorescence assays were also positive by real time PCR. There was no relation between the negativity by QuickVue® RSV Test and viral load or specific strain. The QuickVue® RSV Test showed sensitivity of 90%, specificity of 98.8%, predictive positive value of 99.3%, and negative predictive value of 94.6%, with accuracy of 93.2% and agreement κ index of 0.85 in comparison to immunofluorescence assay. Conclusions: This study demonstrated that the QuickVue® RSV Test Kit can be effective in early detection of Respiratory syncytial virus in nasopharyngeal aspirate and is reliable for use as a diagnostic tool in pediatrics.

Resumo Objetivo: Avaliar o teste QuickVue® RSV Test Kit (QUIDEL Corp, CA, EUA) para o diagnóstico rápido do vírus sincicial respiratório em crianças com doença respiratória aguda, comparandoo com a imunofluorescência indireta como padrão ouro. Visto que, no Brasil, testes rápidos para detecção de antígenos para vírus sincicial respiratório não são rotineiramente utilizados como ferramenta de diagnóstico, exceto para Dengue e Influenza. Métodos: Um total de 486 amostras de aspirado de nasofaringe de crianças menores de 5 anos com doença respiratória aguda, coletadas entre dezembro de 2013 e agosto de 2014, foram analisadas por imunofluorescência e pelo teste QuickVue®. Amostras com resultados discordantes entre os métodos foram submetidas a PCR em tempo real e sequenciamento. Resultados: Das 313 amostras positivas por IFI, 282 foram positivas no teste rápido (90%), 2 amostras foram positivas apenas no teste rápido (0.6%), 33 apenas na imunofluorescência (10.5%) e 171 foram negativas em ambos os métodos. As 35 amostras com resultados discordantes foram testadas por PCR em tempo real, sendo que duas que foram positivas apenas no teste rápido e 5 apenas na imunofluorescência confirmaram-se positivas. Não houve relação entre a ausência de positividade no teste QuickVue® com a carga ou com a cepa viral. O teste QuickVue® mostrou sensibilidade de 90.1%, especificidade 98.9%, valor preditivo positivo 99.3%, valor preditivo negativo de 94.6%, acurácia de 93.2% e índice de concordância de 0.85 em comparação à imunofluorescência. Conclusões: Nosso estudo demonstrou que o teste QuickVue® RSV pode ser efetivo na detecção precoce do vírus sincicial respiratório em amostras de aspirado de nasofaringe e é confiável como uma ferramenta de diagnósticos em pediatria.

Lack of association between viral load and severity of acute bronchiolitis in infants / Falta de associação entre carga viral e gravidade da bronquiolite aguda em lactentes

ABSTRACT Objective: To investigate the correlation between respiratory syncytial viral load and length of hospitalization in infants with acute wheezing episodes. Methods: This was a two-year, cross-sectional study of infants ≤ 12 months of age with bronchiolitis at the time of admission to a tertiary hospital. For the identification of respiratory viruses, nasopharyngeal secretions were collected. Samples were analyzed (throughout the study period) by direct immunofluorescence and (in the second year of the study) by quantitative real-time PCR. We screened for three human viruses: rhinovirus, respiratory syncytial virus, and metapneumovirus. Results: Of 110 samples evaluated by direct immunofluorescence, 56 (50.9%) were positive for a single virus, and 16 (14.5%) were positive for two or more viruses. Among those 72 samples, the most prevalent virus was respiratory syncytial virus, followed by influenza. Of 56 samples evaluated by quantitative real-time PCR, 24 (42.8%) were positive for a single virus, and 1 (1.7%) was positive for two viruses. Among those 25 samples, the most prevalent virus was again respiratory syncytial virus, followed by human rhinovirus. Coinfection did not influence the length of the hospital stay or other outcome s. In addition, there was no association between respiratory syncytial virus load and the length of hospitalization. Conclusions: Neither coinfection nor respiratory syncytial viral load appears to influence the outcomes of acute bronchiolitis in infants.

RESUMO Objetivo: Investigar a correlação entre a carga viral do vírus sincicial respiratório e o tempo de internação hospitalar em lactentes com episódios de sibilância aguda. Métodos: Este foi um estudo transversal de dois anos envolvendo lactentes de até 12 meses de idade com bronquiolite no momento da internação em um hospital terciário. Para a identificação dos vírus respiratórios foram coletadas secreções nasofaríngeas. As amostras foram analisadas (por todo o período do estudo) por imunofluorescência direta e (no segundo ano do estudo) por PCR quantitativa em tempo real para três vírus humanos (rinovírus, vírus sincicial respiratório e metapneumovírus). Resultados: Das 110 amostras avaliadas por imunofluorescência direta, 56 (50,9%) foram positivas para um único vírus, e 16 (14,5%) foram positivas para dois ou mais vírus. Nessas 72 amostras, o vírus mais prevalente foi o vírus sincicial respiratório, seguido por influenza. Das 56 amostras avaliadas por PCR quantitativa em tempo real, 24 (42,8%) foram positivas para um único vírus, e 1 (1,7%) foi positiva para dois vírus. Nessas 25 amostras, o vírus mais prevalente foi o vírus sincicial respiratório, seguido por rinovírus humano. A coinfecção não influenciou o tempo de internação ou outros desfechos. Além disso, não houve associação entre a carga viral de vírus sincicial respiratório e o tempo de internação. Conclusões: A coinfecção e a carga viral do vírus sincicial respiratório não parecem influenciar os desfechos em lactentes com bronquiolite aguda.

Respiratory Syncytial Virus Related Readmission in Preterm Infants Less than 34 weeks' Gestation Following Discharge from a Neonatal Intensive Care Unit in Korea

This study was done to evaluate respiratory syncytial virus (RSV) related readmission (RRR) and risk factors of RRR in preterm infants 1 yr after discharge from the NICU, were enrolled. The average GA and birth weight of the infants was 30(+5) +/- 2(+5) weeks and 1,502 +/- 474 g, respectively. The RRR rate of enrolled infants was 8.4% (96/1,140), and RSV accounted for 58.2% of respiratory readmissions of infants who had laboratory tests confirming etiological viruses. Living with elder siblings (odd ratio [OR], 2.68; 95% confidence interval [CI], 1.68-4.28; P < 0.001), and bronchopulmonary dysplasia (BPD) (OR, 2.95; 95% CI, 1.44-6.04; P = 0.003, BPD vs. none) increased the risk of RRR. Palivizumab prophylaxis (OR, 0.06; 95% CI, 0.03-0.13; P < 0.001) decreased the risk of RRR. The risk of RRR of infants of 32-33 weeks' gestation was lower than that of infants < 26 weeks' gestation (OR, 0.11; 95% CI, 0.02-0.53; P = 0.006). This was a nationwide study that evaluated the rate and associated risk factors of RRR in Korean preterm infants. Preterm infants with BPD or living with siblings should be supervised, and administration of palivizumab to prevent RRR should be considered.

Acute respiratory viral infections in pediatric cancer patients undergoing chemotherapy / Infecções respiratórias virais agudas em pacientes pediátricos com câncer em tratamento quimioterápico

OBJECTIVE: to estimate the prevalence of infection by respiratory viruses in pediatric patients with cancer and acute respiratory infection (ARI) and/or fever. METHODS: cross-sectional study, from January 2011 to December 2012. The secretions of nasopharyngeal aspirates were analyzed in children younger than 21 years with acute respiratory infections. Patients were treated at the Grupo em Defesa da Criança Com Câncer (Grendacc) and University Hospital (HU), Jundiaí, SP. The rapid test was used for detection of influenza virus (Kit Biotrin, Inc. Ireland), and real-time multiplex polymerase chain reaction (FTD, Respiratory pathogens, multiplex Fast Trade Kit, Malta) for detection of influenza virus (H1N1, B), rhinovirus, parainfluenza virus, adenovirus, respiratory syncytial virus, human parechovirus, bocavirus, metapneumovirus, and human coronavirus. The prevalence of viral infection was estimated and association tests were used (χ2 or Fisher's exact test). RESULTS: 104 samples of nasopharyngeal aspirate and blood were analyzed. The median age was 12 ± 5.2 years, 51% males, 68% whites, 32% had repeated ARIs, 32% prior antibiotic use, 19.8% cough, and 8% contact with ARIs. A total of 94.3% were in good general status. Acute lymphocytic leukemia (42.3%) was the most prevalent neoplasia. Respiratory viruses were detected in 50 samples: rhinoviruses (23.1%), respiratory syncytial virus AB (8.7%), and coronavirus (6.8%). Co-detection occurred in 19% of cases with 2 viruses and in 3% of those with 3 viruses, and was more frequent between rhinovirus and coronavirus 43. Fever in neutropenic patients was observed in 13%, of which four (30.7) were positive for viruses. There were no deaths. CONCLUSIONS: the prevalence of respiratory viruses was relevant in the infectious episode, with no increase in morbidity and mortality. Viral co-detection was frequent in patients with cancer and ARIs. .

OBJETIVO: estimar a prevalência da infecção pelos vírus respiratórios em pacientes pediátricos com câncer e infecção respiratória aguda (IRA) e/ou febre. MÉTODOS: estudo transversal, de janeiro de 2011 a dezembro de 2012. Foram analisadas secreções de aspirado da nasofaringe de menores de 21 anos, com quadro respiratório agudo, atendidos nos hospitais Grendacc e HU, Jundiaí, SP. Foi aplicado o teste rápido para detecção dos vírus influenza (Kit Biotrin(r)) e a reação em cadeia da polimerase multiplex em tempo real (Kit multiplex/Fast Trade(r)) para detecção dos vírus: influenza (A, H1N1, B), rinovírus, parainfluenza, adenovírus respiratório, vírus respiratório sincicial, parechovírus, bocavírus, metapneumovírus humano e coronavírus humano. Foi estimada a prevalência de infecção viral e usados testes de associação (χ2 ou teste exato de Fisher). RESULTADOS: foram analisadas 104 amostras de aspirado de nasofaringe e sangue. A mediana para a idade foi 12±5,2 anos; masculino (51%); cor branca (68%); IVAS de repetição (32%); uso prévio de antibiótico (32%); tosse (19,8%); e contato com IVAS (8%). Apresentavam-se em bom estado geral 94,3% dos pacientes. A leucemia linfocítica aguda (42,3%) foi mais prevalente. Foram detectados vírus respiratórios em 50% das amostras: rinovírus (23,1%), vírus sincicial respiratório A/B (8,7%) e coronavírus (6,8%). Ocorreu codetecção em 19% entre dois vírus, e de 3% entre três vírus, sendo a mais frequente entre rinovírus e coronavírus 43. Febre em neutropênicos foi de 13%, sendo quatro (30,7%) com vírus positivo. Não houve óbitos. CONCLUSÕES: a prevalência de vírus respiratórios ...

Identificación de virus respiratorios en pacientes pediátricos / Identification of respiratory viruses in pediatric patients

Los virus son la principal causa de infecciones respiratorias agudas. Para la detección de los virus respiratorios se emplea la Inmunofluorescencia directa (IFD). Objetivos: Describir los resultados de las IFD positivas según edad de los pacientes y estacionalidad y determinar el porcentaje de positividad. Material y métodos: Estudio descriptivo retrospectivo. Se incluyeron todas las IFD realizadas en pacientes <15 años en el Hospital de Niños de Viña del Mar entre enero 2012 y noviembre 2013. Resultados: Se realizaron 32015 IFD en 9012 pacientes en ambos años. El virus más frecuente es el Virus Respiratorio Sincicial (VRS) (51 por ciento 2012, 63 porciento 2013), obteniendo un mayor número de casos en pacientes menores de 1año. El Adenovirus (ADV) ocupa el segundo lugar con una incidencia uniforme a lo largo del año. Se observó una disminución de los casos de Influenza A y B desde el año 2012 al 2013. El porcentaje de positividad global de los exámenes es muy bajo (4,25 por ciento 2012 y 3,19 por ciento 2013). El VRS alcanza la mayor positividad en invierno (31,8 por ciento 2012 y24,7 por ciento 2013) y llega al 0 por ciento durante el verano. Conclusiones: Nuestros resultados se asemejan a la epidemiología nacional principalmente en la distribución de los virus según edad y estacionalidad. El virus más frecuentemente encontrado es el VRS. Hubo menos casos de Influenza A durante el 2013 en comparación con los resultados en el país. Existe una solicitud aumentada de exámenes lo que lleva a un porcentaje de positividad muy bajo...

The main cause of acute respiratory infections is viral. The direct immunofluorescence (IF) is used in the detection of respiratory viruses. Objectives: To describe the results of positive IF in relationship to the patient´s age and seasonality and to determine the percentage of positive results. Material and Methods: A descriptive retrospective study that includes all IF performed in patients <15 years old in a private clinic in the V region from January 2012 to November 2013. Results: 32015 IF were conducted in 9012 patients during both years. The Respiratory Syncytial Virus (RSV) is the most common virus (51 percent 2012, 63 percent 2013), obtaining a larger number of cases in patients under the age of 1. The second most common virus is Adenovirus (ADV) with a uniform incidence during the year. A decrease in cases of Influenza A and B was observed from 2012 to 2013. The percent positivity of the tests is very low (4.25 percent and 3.19 percent 2012 2013). The RSV positive testing is higher during the winter (31.8 percent and 24.7 percent 2012 2013) and 0 percent during the summer. Conclusions: Our results are similar to the ones obtained by the national epidemiology in terms of age and season relationship. The RSV is the most common virus. There were fewer cases of influenza A in 2013 compared with results in the country. Due to high demand in IF testing, a very low percentage of positive results is observed...

Epidemiological aspects of influenza A related to climatic conditions during and after a pandemic period in the city of Salvador, northeastern Brazil

During the influenza pandemic of 2009, the A(H1N1)pdm09, A/H3N2 seasonal and influenza B viruses were observed to be co-circulating with other respiratory viruses. To observe the epidemiological pattern of the influenza virus between May 2009-August 2011, 467 nasopharyngeal aspirates were collected from children less than five years of age in the city of Salvador. In addition, data on weather conditions were obtained. Indirect immunofluorescence, real-time transcription reverse polymerase chain reaction (RT-PCR), and sequencing assays were performed for influenza virus detection. Of all 467 samples, 34 (7%) specimens were positive for influenza A and of these, viral characterisation identified Flu A/H3N2 in 25/34 (74%) and A(H1N1)pdm09 in 9/34 (26%). Influenza B accounted for a small proportion (0.8%) and the other respiratory viruses for 27.2% (127/467). No deaths were registered and no pattern of seasonality or expected climatic conditions could be established. These observations are important for predicting the evolution of epidemics and in implementing future anti-pandemic measures.

Etiological diagnosis reduces the use of antibiotics in infants with bronchiolitis

OBJECTIVE: Acute bronchiolitis is a leading cause of infant hospitalization and is most commonly caused by respiratory syncytial virus. Etiological tests are not required for its diagnosis, but the influence of viral screening on the therapeutic approach for acute bronchiolitis remains unclear. METHODS: A historical cohort was performed to assess the impact of viral screening on drug prescriptions. The study included infants up to one year of age who were hospitalized for bronchiolitis. Virus screening was performed using immunofluorescence assays in nasopharyngeal aspirates. The clinical data were obtained from the patients' medical records. Therapeutic changes were considered to be associated with viral screening when made within 24 hours of the release of the results. RESULTS: The frequency of prescriptions for beta agonists, corticosteroids and antibiotics was high at the time of admission and was similar among the 230 patients. The diagnosis of pneumonia and otitis was associated with the introduction of antibiotics but did not influence antibiotics maintenance after the results of the virus screening were obtained. Changes in the prescriptions were more frequent for the respiratory syncytial virus patients compared to patients who had negative viral screening results (p =0.004), especially the discontinuation of antibiotics (p<0.001). The identification of respiratory syncytial virus was associated with the suspension of antibiotics (p= 0.003), even after adjusting for confounding variables (p = 0.004); however, it did not influence the suspension of beta-agonists or corticosteroids. CONCLUSION: The identification of respiratory syncytial virus in infants with bronchiolitis was independently associated with the discontinuation of antibiotics during hospitalization.

Respiratory syncytial virus, infants and intensive therapy

The aims of this study were to determine the presence of respiratory syncytial virus (RSV) and to assess the clinical features of the disease in infants with acute low respiratory tract infection hospitalized at pediatric intensive care units (PICU) of two university teaching hospitals in São Paulo State, Brazil. Nasopharyngeal secretions were tested for the RSV by the polymerase chain reaction. Positive and negative groups for the virus were compared in terms of evolution under intensive care (mechanical pulmonary ventilation, medications, invasive procedures, complications and case fatality). Statistical analysis was performed using the Mann Whitney and Fisher's exact tests. A total of 21 infants were assessed, 8 (38.1 percent) of whom were positive for RSV. The majority of patients were previously healthy while 85.7 percent required mechanical pulmonary ventilation, 20/21 patients presented with at least one complication, and the fatality rate was 14.3 percent. RSV positive and negative groups did not differ for the variables studied. Patients involved in this study were critically ill and needed multiple PICU resources, independently of the presence of RSV. Further studies involving larger cohorts are needed to assess the magnitude of the impact of RSV on the clinical evolution of infants admitted to the PICU in our settings.

Determinación de subtipos del virus respiratorio sincicial en muestras positivas por el virus, aisladas en el Hospital Nacional de Niños / Detection of human respiratory syncytial virus subtypes A and B in hospitalized children in Costa Rica

Objetivo: El virus respiratorio sincicial, VRS, es un pneumovirus de la familia Paramyxovridae, que causa enfermedad severa del tracto respitaroio inferior en neonatos y niños pequeños, especialmente en los primeros años de vida. Es responsable de constantes hospitalizaciones y visitas a los servicios de emergencias. Se han identificado dos subtipos: VRS-A y VRS-B, mediante anticuerpos monoclonales y técnicas moleculares. El objetivo de este estudio fue establecer por primera vez la circulación de ambos subtipos del VRS, en muestras positivas de niños hospitalizados durante el pico estacional de 2008, en el Hospital Nacional de Niños, HNN. Métodos: Se analizaron 49 muestras de aspirados nasofaríngeos de niños hospitalizados, de un total de 578, de las cuales 197 fueron previamente positivas para VRS por inmunofluorescencia directa. Se realizó cultivo celular, y un RT-PCR múltiple, estandarizado en el laboratorio, para detectar VRS-A y VRS-B. Resultados: La frecuencia del VRS fue del 34 por ciento en el HNN, para agosto y septiembre de 2008. De las 49 muestras analizadas por RT-PCR, 41, 84 por ciento, fueron positivas, 34, 83 por ciento, por el subtipo A y 7, 17 por ciento, por el B; 8 fueron negativas. Ningún paciente presentó infección mixta y no hubo diferencia entre los síntomas, la edad o el origen geográfico de los niños. El cultivo fue positivo solo en el 30 por ciento de las muestras. Conclusión: La frecuencia del VRS para el periodo en estudio fue del 34 por ciento de las muestras analizadas en aspirados nasofaríngeos. Este es el primer reporte de la detección de los subtipos A y B del VRS, en una pequeña cohorte del HNN, confirmados por un RT-PCR múltiple estandarizado en el laboratorio.

High rate of viral identification and coinfections in infants with acute bronchiolitis

OBJECTIVES: To determine the viruses and risk factors associated with hospital and intensive care unit (ICU) admissions in infants with acute bronchiolitis. INTRODUCTION: Bronchiolitis is a major cause of morbidity in infants. Widespread use of molecular-based methods has yielded new insights about its etiology, but the impact of viral etiologies on early outcomes is still unclear. METHODS: Seventy-seven infants with bronchiolitis who were under two years of age and visited an emergency unit were included. Using molecular-based methods, samples were tested for 12 different respiratory viruses. Logistic regression models were used to identify clinical and virological variables associated with the main endpoints: hospital admission and ICU admission. RESULTS: We identified at least one virus in 93.5 percent of patients, and coinfections were found in nearly 40 percent of patients. RSV was the most common pathogen (63.6 percent), followed by rhinovirus (39 percent). Identification of RSV was only associated with an increased risk of hospital admission in the univariate model. Younger age and enterovirus infection were associated with an increased risk of hospital admission, while atopy of a first-degree relative showed a protective effect. Prematurity was associated with an increased risk of admission to the ICU. Coinfections were not associated with worse outcomes. CONCLUSIONS: Molecular-based methods resulted in high rates of viral identification but did not change the significant role of RSV in acute bronchiolitis. Younger age and enterovirus infection were risk factors for hospital admission, while prematurity appeared to be a significant risk factor for admission to the ICU in acute viral bronchiolitis.

Parainfluenza virus infections in a tropical city: clinical and epidemiological aspects

Little information on the epidemiology and clinical characteristics of human parainfluenza virus (HPIV) infections, especially in children from tropical countries, has been published. The aim of this study was to determine the frequency of HPIV infections in children attended at a large hospital in Fortaleza in Northeast Brazil, and describe seasonal patterns, clinical and epidemiological characteristics of these infections. From January 2001 to December 2006, a total of 3070 nasopharyngeal aspirates collected from children were screened by indirect immunofluorescence for human parainfluenza viruses 1, 2, and 3 (HPIV-1, 2 and 3) and other respiratory viruses. Viral antigens were identified in 933 samples and HPIV in 117. The frequency of HPIV-3, HPIV-1 and HPIV-2 was of 83.76 percent, 11.96 percent and 4.27 percent, respectively. Only HPIV-3 showed a seasonal occurrence, with most cases observed from September to November, and with an inverse relationship to the rainy season. Most HPIV-3 infections seen in outpatients were diagnosed as upper respiratory tract infections.

Comparison of direct immunofluorescence, conventional cell culture and polymerase chain reaction techniques for detecting respiratory syncytial virus in nasopharyngeal aspirates from infants / Comparação entre imunofluorescência direta, cultura convencional de células e reação em cadeia de polimerase para detectar vírus respiratório sincicial em lavados de nasofaringe de crianças

A total of 316 samples of nasopharyngeal aspirate from infants up to two years of age with acute respiratory-tract illnesses were processed for detection of respiratory syncytial virus (RSV) using three different techniques: viral isolation, direct immunofluorescence, and PCR. Of the samples, 36 (11.4 percent) were positive for RSV, considering the three techniques. PCR was the most sensitive technique, providing positive findings in 35/316 (11.1 percent) of the samples, followed by direct immunofluorescence (25/316, 7.9 percent) and viral isolation (20/315, 6.3 percent) (p < 0.001). A sample was positive by immunofluorescence and negative by PCR, and 11 (31.4 percent) were positive only by RT-PCR. We conclude that RT-PCR is more sensitive than IF and viral isolation to detect RSV in nasopharyngeal aspirate specimens in newborn and infants.

Um total de 316 amostras de lavado de nasofaringe obtidas de crianças em acompanhamento ambulatorial com até dois anos de idade durante episódio de doença aguda do trato respiratório foram processadas para detecção do vírus sincicial respiratório (VSR) utilizando três diferentes técnicas: isolamento viral, imunofluorescência direta e reação em cadeia por polimerase (RT-PCR). Destas amostras, 36 (11,4 por cento) foram positivas para o VSR. A RT-PCR foi a técnica mais sensível, com positividade em 35 (11,1 por cento) das amostras, seguindo-se a imunofluorescência direta (25/316, 7,9 por cento) e o isolamento viral (20/315, 6,3 por cento) (p < 0,001). Uma amostra foi positiva pela imunofluorescência e negativa pela RT-PCR, e 11/36 (31,4 por cento) foram positivas somente pela RT-PCR. Concluímos que a RT-PCR é mais sensível que a imunofluorescência e o isolamento viral para detecção do VRS em amostras de aspirado de nasofaringe de recém-nascidos e lactentes.

Human metapneumovirus and respiratory syncytial virus detection in young children with acute bronchiolitis.

This study was conducted to detect human metapneumovirus (hMPV) and respiratory syncytial virus (RSV) in young children hospitalized with acute bronchiolitis, using reverse transcriptase polymerase chain reaction (RT-PCR). Nasopharyngeal secretions were collected from 170 children between 1 and 24 months of age admitted to two tertiary hospitals in northeastern Thailand, between 2002 and 2004. Acute bronchiolitis was defined as the first episode of wheezing associated with tachypnea, increased respiratory effort and an upper respiratory tract infection. Two-thirds (115/170) were positive for viral etiologies: 64.7% RSV (110/170) and 3.5% hMPV (6/170). One patient had a dual infection. hMPV was detected between August and November, while RSV was prevalent from July through March. The clinical manifestations among the 6 hMPV, RSV and non-RSV-infected children were similar. RSV was the leading cause of acute bronchiolitis in young children and hMPV had a low prevalence in northeastern Thailand.

Virus Respiratorios en Menores de Diez Años con Infección Respiratoria en el Hospital Militar Central de Bogotá 2000-2001 / Respiratory virus in children aged less than 10 years old suffering from respiratory infection in the Hospital Militar Central in Bogota from 2000-2001

Objetivo: Se llevo a cabo un estudio en niños que consultaban por infección respiratoria aguda al Hospital Militar (Hosmil) de Bogota, Colombia, con el objetivo de estimar la frecuencia de enfermedad respiratoria aguda en esa institución producida por algunos virus respiratorios. Métodos: Durante 18 meses, de Marzo de 2000 a Septiembre de 2001, se seleccionaron semanalmente tres a cinco niños con infección respiratoria de aquellos que consultaban al servicio de emergencia o de consulta ambulatoria del Hospital. De cada uno de ellos se obtuvo muestras nasofaringeas que fueron examinadas por inmunofluorescencia para virus sincitial respiratorio (VSR), influenza, adenovirus y parainfluenza. Resultados: Se estudiaron 139 niños de los cuales el 40 por ciento fue positivo para alguno de los virus estudiados. El agente viral mas frecuentemente encontrado fue el VSR (27 por ciento), seguido por el virus de la influenza (5 por ciento) y adenovirus (3 por ciento). La circulación de VSR coincidía con los picos de hospitalizaciones por IRA y por neumonía y del hospital, era mas frecuente en los niños menores de 3 años y se encontraba presente durante todo el año. Conclusiones: Los virus respiratorios causan gran parte de la enfermedad respiratoria moderada o severa en el Hosmil y el VSR es el agente más importante entre ellos.

Objective: A study was carried out on children seeking medical care at the Hospital Militar (Hosmil) in Bogota due to acute respiratory infection; it was aimed at estimating the frequency of respiratory virus-associated acute respiratory disease (ARD) in children aged under 10. Methods: Three to five children aged less than 10 years old were selected every week from the hospital's emergency ward or ambulatory services over an 18-month period from March 2000 to September 2001. Nasopharyngeal samples were obtained from them and processed using indirect immunofluorescence. The relative frequency of respiratory syncytial virus (RSV), influenza, adenovirus and parainfluenza were calculated. Results: Around 40 percent of the 139 children examined proved positive for at least one respiratory virus. RSV was the most frequently found virus (27 percent positivity: 38 patients) followed by influenza (5 percent: 7 patients) and adenovirus (3 percent: 4 patients). RSV circulation peaks coincided with peaks related to ARD and pneumonia in the hospital: it was found most frequently in children aged less than 3 and was present throughout the year. Conclusion: Respiratory viruses were an important cause of moderate to severe respiratory illness in children seeking health care at Hosmil; RSV was the leading agent amongst such viruses.

Comparison between ectodomain and G2 region of G glycoprotein for genotyping of HRSV

The Human Respiratory Syncytial Virus (HRSV), isolated in 1955, is the main cause of hospitalization of babies and infants with respiratory illness. Several studies have been conducted worldwide aiming the development of a safe and effective vaccine against HRSV. The G2 region of glycoprotein G is used as genotyping default. In the present study, we performed a phylogenetic analysis of G protein and a comparative study between G2 region and ectodomain of attachment glycoprotein. Fifty-three nasal swab samples from children less than 5 years old and presenting symptoms of acute respiratory illness, assisted at the University Hospital (UH) of University of Sao Paulo (USP) in 2004, were submitted to sequencing by PCR and compared with GenBank sequences. We concluded that the G2 region is adequate for HRSV genotyping.

O vírus respiratório sincicial humano (HRSV), isolado em 1955, é a principal causa da hospitalização de bebês e crianças pequenas com sintomas de doença respiratória. No mundo inteiro, vários estudos para o desenvolvimento de uma vacina segura e eficiente contra o HRSV têm tido alta prioridade. A região G2 da glicoproteína G é usada como padrão para genotipagem do HRSV. Neste estudo, foi realizada a análise filogenética da glicoproteína G e o estudo comparativo entre a região G2 e o ectodomínio dessa glicoproteína. Cinquenta e três amostras de swab nasal de crianças com menos de cinco anos de idade, apresentando doença respiratória aguda, atendidas no Hospital Universitário (HU) da Universidade de São Paulo durante o ano de 2004, foram submetidas a sequenciamento por PCR e comparadas com seqüências do GenBank. A região G2 mostrou ser adequada para a genotipagem do HRSV.

Isolation of respiratory syncytial virus from nasopharyngeal aspirates stored at 20°C from one to fifteen months after collection

Cell culture isolation is used for recovering respiratory syncytial virus (RSV) from respiratory specimens. As RSV is a thermolabile virus, specimens destined for inoculation into cell culture require special transport, handling, and storage. The isolation rate of RSV from nasopharyngeal aspirates (NPA) stored at 20°C for one to 15 months after collection was investigated. A total of 126 samples considered positive for RSV by indirect fluorescence-antibody were tested by virus isolation in HEp-2 cell culture. RSV was isolated from 47/126 specimens (37.3 percent). These results show that RSV may be recovered from NPA stored at 20°C by cell culture.

Etiology of acute lower respiratory tract infection.

OBJECTIVE: To identify pathogens responsible for acute severe lower respiratory tract infection (ALRTI) in under five children by non-invasive methods. METHOD: 95 children hospitalized with acute severe lower respiratory tract infection were investigated for identification of viruses, bacteria, chlamydia or mycoplasma by nasopharyngeal aspirates, blood culture and serology. RESULT: Etiological agents could be identified in 94% of the patients. Viruses from NP aspirate could be isolated in 36 (38%), bacterial isolates from blood cultures in 15 (16%); mycoplasma was identified in 23 (24%) and chlamydia in 10 (11%) by serological tests; mixed infections were present in 8 (8%) patients. CONCLUSION: Noninvasive methods can be useful in identifying etiological agents in severe ALRTI.

incorporación de la técnica de RT-PCR para la detección del virus sincitial respiratorio / Incorporation of the RT-PCR technique to the detection of respiratory syncitial virus

Objetivo: Estandarizar e incorporar técnicas de biología molecular, RT-PCR para la detección del virus sincitial respiratorio que complementen y enriquezcan el diagnóstico.Material y métodos: se utilizaron cepas de referencia del virus sincitial respiratorio de los grupos A y B (virus stock ATCC), las cuales se propagaron y titularon en células HEp-2. Se realizaron pruebas de inmunofluorescencia indirecta y de la prueba RT-PCR. Para ello se extrajo el ARN del virus con trizol, se realizó una transcripción reversa para obtener ADNc y, para la PCR se utilizaron oligonucleótidos que amplifican un fragmento del gen de la proteína G del virus sincitial respiratorio. Para comprobar la especificidad de la prueba se utilizaron virus de la misma familia (sarampión y parainfluenza) y virus de diferentes familias (influenza y adenovirus). Al evaluar la sensibilidad se utilizaron diferentes diluciones del ADNc viral.Resultados: en el cultivo, el efecto citopático se puede observar claramente del cuarto al octavo día. La prueba de inmunofluorescencia como se sabe es una técnica sensible y específica para el virus. La RT-PCR que se desarrollo, fue efectiva para la amplificación del ADNc; además, mostró ser específica para el virus sincitial respiratorio, ya que no amplifica material genético de otros virus incluyendo a aquellos que pertenecen a la misma familia. La sensibilidad de la prueba es alta, alcanzando a amplificar hasta picogramos de ADNc.Conclusiones: la rapidez de la inmunofluorescencia, permite dar un diagnóstico presuntivo que después puede ser comprobado por el aislamiento y propagación del virus en cultivo celular. La técnica de RT-PCR con los oligonucleótidos que utilizamos fue sensible, específica y rápida, por tanto debe ser tomada en cuenta para el apoyo al diagnóstico clínico. Con lo anterior, no se trata de sustituir las técnicas tradicionales, sino contar con mayores opciones y además reforzarlas; de esta manera, se podrá fundamentar mejor el diagnóstico de las infecciones virales.

Implementación del método rápido de diagnóstico de virus por inmunofluorescencia en niños hospitalizados por infecciones respiratorias agudas / A quick viral diagnostic method by immunofluorescence in acute respiratoty illnes in hospitalized children

Las infecciones respiratorias agudas (IRA) constituyen una causa importante de morbimortalidad en pediatría donde los virus tienen un papel relevante, los cuales pueden ser diagnosticados por la inmunofluorescencia directa IFD con sensibilidad similar al aislamiento en cultivos. El objetivo del estudio fue evaluar la frecuencia de agentes virales asociados a IRA en niños internados por esta causa en diferentes hospitales del país y conocer el aspecto clínico-epidemiológico. Se realizó un estudio de corte transversal donde se analizaron por inmunofluorescencia, aspirados nasofaríngeos, secreciones traqueales, nasales, lavados bronquiales. Se estudiaron 111 muestras de enero a octubre de 1997 de niños de 15 días a 10 años identificándose un agente viral en 59 de los casos. Los agentes hallados fueron Virus Sincicial Respiratorio (VSR) 47 por ciento, el Parainfluenza 1, 2, 3 (5,4 por ciento), el Adenovirus(3,6 por ciento), el Influenza A (5,4 por ciento), Influenza B (1,8 por ciento). Los patrones clínicos fueron Bronquiolitis (49 por ciento), Neumonías (42 por ciento) y Croup (8,5 por ciento). Los VSR se identificaron con mayor frecuencia con pico en agosto; (63 por ciento) en lactantes menores. El virus de influenza A se presentó con temporalidad similar y se relacionó con casos severos en niños mayores de 5 años, en el Chaco. El Parainfluenza se observó en menores de 1 año. El Adenovirus fue más esporádico pero uno de ellos se relacionó a un caso fatal. Se observaron asociaciones de agentes virales. Con esta técnica diagnóstico útil se dispone del primer dato sobre la epidemiología de las afecciones respiratorias agudas de probable etiología viral en la población infantil del país que requirió hospitalización, siendo similar a lo observado en otros países