The genomic evolutionary dynamics and global circulation patterns of respiratory syncytial virus.

Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory tract infection in young children and the second leading cause of infant death worldwide. While global circulation has been extensively studied for respiratory viruses such as seasonal influenza, and more recently also in great detail for SARS-CoV-2, a lack of global multi-annual sampling of complete RSV genomes limits our understanding of RSV molecular epidemiology. Here, we capitalise on the genomic surveillance by the INFORM-RSV study and apply phylodynamic approaches to uncover how selection and neutral epidemiological processes shape RSV diversity. Using complete viral genome sequences, we show similar patterns of site-specific diversifying selection among RSVA and RSVB and recover the imprint of non-neutral epidemic processes on their genealogies. Using a phylogeographic approach, we provide evidence for air travel governing the global patterns of RSVA and RSVB spread, which results in a considerable degree of phylogenetic mixing across countries. Our findings highlight the potential of systematic global RSV genomic surveillance for transforming our understanding of global RSV spread.

Nirsevimab binding-site conservation in respiratory syncytial virus fusion glycoprotein worldwide between 1956 and 2021: an analysis of observational study sequencing data.

BACKGROUND: Nirsevimab is an extended half-life monoclonal antibody to the respiratory syncytial virus (RSV) fusion protein that has been developed to protect infants for an entire RSV season. Previous studies have shown that the nirsevimab binding site is highly conserved. However, investigations of the geotemporal evolution of potential escape variants in recent (ie, 2015-2021) RSV seasons have been minimal. Here, we examine prospective RSV surveillance data to assess the geotemporal prevalence of RSV A and B, and functionally characterise the effect of the nirsevimab binding-site substitutions identified between 2015 and 2021. METHODS: We assessed the geotemporal prevalence of RSV A and B and nirsevimab binding-site conservation between 2015 and 2021 from three prospective RSV molecular surveillance studies (the US-based OUTSMART-RSV, the global INFORM-RSV, and a pilot study in South Africa). Nirsevimab binding-site substitutions were assessed in an RSV microneutralisation susceptibility assay. We contextualised our findings by assessing fusion-protein sequence diversity from 1956 to 2021 relative to other respiratory-virus envelope glycoproteins using RSV fusion protein sequences published in NCBI GenBank. FINDINGS: We identified 5675 RSV A and RSV B fusion protein sequences (2875 RSV A and 2800 RSV B) from the three surveillance studies (2015-2021). Nearly all (25 [100%] of 25 positions of RSV A fusion proteins and 22 [88%] of 25 positions of RSV B fusion proteins) amino acids within the nirsevimab binding site remained highly conserved between 2015 and 2021. A highly prevalent (ie, >40·0% of all sequences) nirsevimab binding-site Ile206Met:Gln209Arg RSV B polymorphism arose between 2016 and 2021. Nirsevimab neutralised a diverse set of recombinant RSV viruses, including new variants containing binding-site substitutions. RSV B variants with reduced susceptibility to nirsevimab neutralisation were detected at low frequencies (ie, prevalence <1·0%) between 2015 and 2021. We used 3626 RSV fusion-protein sequences published in NCBI GenBank between 1956 and 2021 (2024 RSV and 1602 RSV B) to show that the RSV fusion protein had lower genetic diversity than influenza haemagglutinin and SARS-CoV-2 spike proteins. INTERPRETATION: The nirsevimab binding site was highly conserved between 1956 and 2021. Nirsevimab escape variants were rare and have not increased over time. FUNDING: AstraZeneca and Sanofi.

Definición de displasia broncopulmonar propuesta por la Comisión Neo SOCHINEP / Definition of bronchopulmonary dysplasia proposed by the Neo SOCHINEP Commission

La displasia broncopulmonar (DBP) es la enfermedad crónica más frecuente del recién nacido prematuro. Los avances en su prevención y tratamiento han permitido una mayor sobrevida de prematuros más pequeños, pero su incidencia se ha mantenido estable en el tiempo, con una fisiopatología y presentación clínica que abarca un amplio espectro y que difiere de la DBP descrita originalmente hace más de 50 años. Aún existen controversias en su definición, la que se ha establecido en base al tratamiento, específicamente al requerimiento de soporte respiratorio. Las definiciones más utilizadas son el requerimiento de oxígeno por 28 días y a las 36 semanas de edad gestacional corregida (EGC). Recientemente se ha propuesto definirla en base al requerimiento de ventilación mecánica a las 36 semanas de EGC, lo que identificaría a los prematuros con DBP más grave y mayor probabilidad de complicaciones respiratorias y neurológicas en los 2 primeros años de vida. Nuestro objetivo en la comisión de Neo-SOCHINEP es el de recomendar la definición y clasificación que nos parece más adecuada para identificar a los prematuros portadores de DBP, considerando los aspectos fisiopatológicos, del compromiso de la función pulmonar y consecuencias prácticas de la definición en nuestro medio. También proponemos la definición del requerimiento de oxígeno en el prematuro cuando esta en neonatología, las condiciones e interpretación de la saturometría contínua cuando está pronto al alta y el seguimiento de la oxigenoterapia posterior al alta.

Bronchopulmonary dysplasia (BPD) is the most frequent chronic disease of the premature newborn. Advances in its prevention and treatment have allowed a greater survival of smaller preterm infants, but its incidence has remained stable over time, with a pathophysiology and clinical presentation that covers a wide spectrum and differs from the BPD originally described more than 50 years ago. There are still controversies in its definition, which has been established based on the treatment, specifically the requirement of respiratory support. The most used definitions are the oxygen requirement for 28 days and at 36 weeks of postmenstrual age (PMA). It has recently been proposed a definition based on the requirement of mechanical ventilation at 36 weeks of PMA, which would identify premature infants with more severe BPD and a greater probability of respiratory and neurological complications in the first 2 years of life. Our objective in the Neo-SOCHINEP commission is to recommend the definition and classification that we believe is most appropriate to identify premature infants with BPD, considering the pathophysiological aspects, the compromised lung function, and practical consequences of the definition in our medium. We also propose the definition of the oxygen requirement in premature infants when they are in neonatology, the conditions and interpretation of continuous saturation when they are soon discharged, and the follow-up of post-discharge oxygen therapy.

Diabetes de inicio precoz en pacientes con fibrosis quística, a propósito de 3 casos / Early-onset diabetes in patients with cystic fibrosis, about 3 cases

INTRODUCCIÓN. La diabetes es la complicación extrapulmonar más frecuente en adultos con fibrosis quística. Existen escasas publicaciones de diabetes relacionada a la fibrosis quística en preescolares a nivel mundial. En Chile se desconoce su prevalencia. MÉTODO. Reportamos una serie de tres casos de niños con fibrosis quística (FQ) y diagnóstico de diabetes a muy temprana edad. RESULTADOS. Caso 1: Niño de 8 años, con diagnóstico de fibrosis quística a los 3 meses de vida por test de sudor y estudio genético p.Phe508del /-. Presenta hiperglicemia no cetósica desde los 6 meses de edad, con colonización traqueal de Staphylococcus Aureus (SA) y Pseudomona Aeruginosa (PA) y debut de diabetes a los 2 años 1 mes. Caso 2: Niño de 16 años, a los 7 meses de vida se diagnostica FQ por test de sudor y estudio genético p.Phe508del /-. Presenta colonización traqueal por SA y múltiples infecciones por PA. A los 5 años 7 meses se diagnostica diabetes presentando cetosis al debut. Caso 3: Niño de 13 años, con diagnóstico de FQ a los 7 meses de vida mediante test de sudor y estudio genético p.Phe508del/-. Presenta colonización traqueal por SA y múltiples infecciones por PA, se realiza diagnóstico de diabetes a los 2 años 7 meses de edad. DISCUSIÓN: La diabetes asociada a fibrosis quística es una complicación frecuente en adultos con fibrosis quística, pero puede presentarse desde edades tempranas. Se debe tener alto nivel de sospecha para el diagnóstico oportuno y óptimo manejo.

INTRODUCTION: Diabetes is the most common extra pulmonary complication in adults with cystic fibrosis (CF). There are few reports of diabetes related to (CF) in preschool children worldwide. Prevalence in Chile is unknown. MÉTODO: We report ta serie of three cases of children with CF and diagnosis of diabetes at an early age. Case 1: Boy 8 year old, CF diagnosed at the age of 3 months by sweat test and genetic study p.Phe508del/-. He presented non-ketotic hyperglycemia since he was 6 months old, with tracheal colonization of Staphylococcus Aureus (SA) and Pseudomona Aeruginosa (PA) , and diagnosis of diabetes at the age of 2 years 1 month. Case 2: Boy patient, 16 years old, with diagnosis of CF at the of age 7 months by sweat test and genetic study p.Phe508del/-. He presents tracheal colonization by SA and multiple PA infections. At the age 5 years 7 months, diabetes is diagnosed, presenting ketosis at the beginning. Case 3: Boy 13 years diagnosed with CF at the age of 7 months, presented sweat test and genetic study p.Phe508del/-. He presents tracheal colonization by SA and multiple infections. DISCUSSION: CF related diabetes is common in adults with cystic fibrosis, but it can be diagnosed in early childhood. A high level of suspicious is required for a proper and timely diagnosis

Prevalencia de aspergilosis broncopulmonar alérgica en niños con fibrosis quística / Prevalence of bronchopulmonary aspergillosis in children with cystic fibrosis

La aspergilosis broncopulmonar alérgica (ABPA) es una reacción de hipersensibilidad secundaria al Aspergillus fumigatus (Af) que complica la evolución en fibrosis quística (FQ). Existen pocos estudios pediátricos de su prevalencia publicados en el mundo y en Chile se desconoce. El objetivo de este trabajo fue estimar la prevalencia de ABPA en niños con FQ en un hospital de referencia, explorar factores de riesgo y describir los criterios diagnósticos, tratamiento y evolución. Se incluyeron retrospectivamente los niños con FQ atendidos en un hospital terciario en Santiago de Chile (Hospital Roberto del Río) entre los años 2011 a 2019, se identificaron aquellos con diagnóstico de ABPA. Se registraron criterios diagnósticos según la Cystic Fibrosis Foundation, presencia de factores de riesgo, tratamientos recibidos y efectos adversos. De 65 pacientes con FQ atendidos en este período, la prevalencia de ABPA fue del 12%. El promedio de edad al diagnóstico fue ± 11 años (5-17 años), predominando la edad adolescente y el género masculino. El 50% cumplieron con los criterios clásicos, el 87,5% usaron antibióticos y el 62,5% corticoides inhalados. La respuesta favorable al tratamiento inicial con corticoides y antifúngico vía oral fue 62,5%, con una exacerbación al momento del estudio. El 25% se comportaron como refractario y el 12,5% respondieron a tratamiento con pulsos de metilprednisolona. El 37,5% presentaron eventos adversos relacionados a corticoides. La prevalencia de ABPA observada es comparable a las series publicadas. Se necesitan trabajos prospectivos para conocer la prevalencia nacional y su tendencia a lo largo de los años, identificando factores de riesgo.

Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity response to Aspergillus fumigatus (Af) and worsens outcome in children with cystic fibrosis (CF). Its prevalence varies in the literature, but we do not know it in Chile. The aim of the study was to know the prevalence of ABPA in children with CF and to describe risk factors, diagnostic criteria, treatment and outcome. We included all patients with CF seen in a tertiary hospital in Santiago, Chile (Hospital Roberto del Río), between 2011 and 2019; ABPA cases (CF Foundation diagnostic criteria) were identified for the estimation of the prevalence. Risk factors, diagnostic criteria and treatment were recorded, as proposed by the Cystic Fibrosis Foundation. A total of 65 patients with CF were identified in the study period, with a prevalence of 12% (8 cases). Mean age at diagnosis ± 11 years (5-17), more frequent in adolescence and male. CF Foundation criteria diagnostic were identified in 50% of cases, with high frequency of antibiotic use (87,5%) and inhaled steroids (62,5%). Positive oral steroids and antifungal treatment response was 62,5%. Refractary response was 25% and 12,5% needed intravenous metilprednisolone pulses. A 37,5% of cases presented adverse effects to steroids. Prevalence of ABPA is comparable to literature. A prospective study is needed to identified national prevalence and trends, identifying risks factors.

Observations from a nationwide vigilance program in medical care for spinal muscular atrophy patients in Chile.

METHODS: Spinal muscular atrophy (SMA) has gained much attention in the last few years because of the approval of the first intrathecal treatment for this neurodegenerative disease. Latin America needs to develop the demographics of SMA, timely access to diagnosis, and appropriate following of the standards of care recommendations for patients. These are essential steps to guide health policies. This was a descriptive study of a cohort of SMA patients from all over Chile. We analyzed the clinical, motor functional, and social data, as well as the care status of nutritional, respiratory and skeletal conditions. We also measured the SMN2 copy number in this population. RESULTS: We recruited 92 patients: 50 male; 23 SMA type-1, 36 SMA type-2 and 33 SMA type-3. The median age at genetic diagnosis was 5, 24 and 132 months. We evaluated the SMN2 copy number in 57 patients. The SMA type-1 patients were tracheostomized and fed by gastrostomy in a 69.6 % of cases, 65% of SMA type-2 patients received nocturnal noninvasive ventilation, and 37% of the whole cohort underwent scoliosis surgery. CONCLUSION: Ventilatory care for SMA type-1 is still based mainly on tracheostomy. This Chilean cohort of SMA patients had timely access to genetic diagnosis, ventilatory assistance, nutritional support, and scoliosis surgery. In this series, SMA type-1 is underrepresented, probably due to restrictions in access to early diagnosis and the high and early mortality rate.

Observations from a nationwide vigilance program in medical care for spinal muscular atrophy patients in Chile / Atrofia muscular espinal en Chile, resultados de un programa de atención médica nacional

ABSTRACT Spinal muscular atrophy (SMA) has gained much attention in the last few years because of the approval of the first intrathecal treatment for this neurodegenerative disease. Latin America needs to develop the demographics of SMA, timely access to diagnosis, and appropriate following of the standards of care recommendations for patients. These are essential steps to guide health policies. Methods This was a descriptive study of a cohort of SMA patients from all over Chile. We analyzed the clinical, motor functional, and social data, as well as the care status of nutritional, respiratory and skeletal conditions. We also measured the SMN2 copy number in this population. Results We recruited 92 patients: 50 male; 23 SMA type-1, 36 SMA type-2 and 33 SMA type-3. The median age at genetic diagnosis was 5, 24 and 132 months. We evaluated the SMN2 copy number in 57 patients. The SMA type-1 patients were tracheostomized and fed by gastrostomy in a 69.6 % of cases, 65% of SMA type-2 patients received nocturnal noninvasive ventilation, and 37% of the whole cohort underwent scoliosis surgery. Conclusion Ventilatory care for SMA type-1 is still based mainly on tracheostomy. This Chilean cohort of SMA patients had timely access to genetic diagnosis, ventilatory assistance, nutritional support, and scoliosis surgery. In this series, SMA type-1 is underrepresented, probably due to restrictions in access to early diagnosis and the high and early mortality rate.

La Atrofia Muscular Espinal (AME) ha concitado mucha atención en los últimos 2 años debido a la aprobación del primer tratamiento intratecal para esta enfermedad neurodegenerativa. América Latina necesita desarrollar la demografía de AME, un acceso oportuno al diagnóstico y un seguimiento apropiado de los pacientes que incorporen los estándares de atención recomendados por expertos. Estos son pasos esenciales para orientar las futuras políticas de salud en esta enfermedad. Métodos Este es un estudio descriptivo de una cohorte de pacientes con AME de todo el país. Se analizaron los datos clínicos, motores, funcionales, sociales y el estado nutricional, respiratorio y esquelético de los pacientes. También medimos el número de copias del gen SMN2 en esta población. Resultados se reclutaron 92 pacientes, 50 varones; 23 AME tipo 1, 36 AME tipo 2 y 33 AME tipo 3. La edad media al diagnóstico genético fue de 5, 24 y 132 meses respectivamente. Evaluamos el número de copias de SMN2 en 57 pacientes. Un 69,6% de los pacientes con AME tipo 1 estaban traqueostomízados y gastrostomizados , un 65% de los pacientes con AME tipo 2 usaban ventilación nocturna no invasiva y el 37% de toda la cohorte presentaba una cirugía de escoliosis. Conclusión Esta cohorte chilena de pacientes con AME tuvo acceso oportuno al diagnóstico genético, asistencia ventilatoria, apoyo nutricional y cirugía de escoliosis, sin embargo, la atención ventilatoria para AME tipo 1 continúa aun basándose principalmente en la traqueostomía. En esta serie, AME tipo 1 está subrepresentada, probablemente debido a las restricciones en el acceso al diagnóstico temprano y la tasa de mortalidad alta y temprana.

Manejo respiratorio en atrofia muscular espinal: cambio de paradigma en la era de las nuevas terapias específicas / Respiratory care in spinal muscular atrophy in the new therapeutic era

Resumen: La atrofia muscular espinal (AME) es la enfermedad genética mortal más frecuente en lactantes, con severidad variable. Se clasifica en cuatro subtipos: tipo 0 de inicio prenatal y recién nacido ya afecta do, con ausencia de esfuerzo respiratorio y ningún desarrollo motor, tipo 1 de inicio en menores de 3 meses que no logran sentarse, tipo 2 que logran sentarse, pero no caminar y tipo 3 que consiguen caminar. La causa más seria de morbimortalidad es la neumonía y la insuficiencia respiratoria. La información a los cuidadores debe contemplarse desde el diagnóstico, para la toma de decisiones anticipadas. Los objetivos del manejo incluyen el estímulo de la tos, evitar la deformación de la caja torácica, la hipoventilación, y tratar oportunamente las infecciones respiratorias, el trastorno de de glución, el reflujo gastroesofágico y la malnutrición. El objetivo de esta actualización es discutir los nuevos desafíos en cuidados respiratorios con un enfoque preventivo, considerando la reciente dis ponibilidad de tratamientos específicos -oligonucleótidos antisentido nusinersen- y otros que están en desarrollo, incluída la terapia génica.

Abstract: Spinal muscular atrophy (SMA) is the first inherited cause of mortality in infants, with four subtypes: SMA0 prenatal onset, SMA1 babies less than 3 months non sitters, SMA2 sitters and SMA3 walkers. Pneumonia and respiratory insufficiency are the most severe complications. Informed parental de cisions are relevant. Respiratory management includes cough assistance, prevention of lung under development due to chest deformity, prompt treatment of respiratory infections, hypoventilation, swallow problems, gastro esophageal reflux and malnutrition. In view of the FDA and EMA approval of the nonsense oligonucleotides nusinersen, the first specific treatment for SMA and the future with gene therapy and others under development, we need to optimize preventive respiratory manage ment with the new standard of care.

[Respiratory care in spinal muscular atrophy in the new therapeutic era]. / Manejo respiratorio en atrofia muscular espinal: Cambio de paradigma en la era de las nuevas terapias específicas.

Spinal muscular atrophy (SMA) is the first inherited cause of mortality in infants, with four subtypes: SMA0 prenatal onset, SMA1 babies less than 3 months non sitters, SMA2 sitters and SMA3 walkers. Pneumonia and respiratory insufficiency are the most severe complications. Informed parental de cisions are relevant. Respiratory management includes cough assistance, prevention of lung under development due to chest deformity, prompt treatment of respiratory infections, hypoventilation, swallow problems, gastro esophageal reflux and malnutrition. In view of the FDA and EMA approval of the nonsense oligonucleotides nusinersen, the first specific treatment for SMA and the future with gene therapy and others under development, we need to optimize preventive respiratory manage ment with the new standard of care.

Infecciones respiratorias agudas bajas: descripción de los egresos del hospital Roberto del Río en el año 2016 / Acute respiratory infections low: description of the discharges of the hospital Roberto del Río in 2016

Las infecciones respiratorias agudas bajas (IRAB) son la principal causa de hospitalización en lactantes, y una de las principales causas de muerte de niños entre un mes y 4 años. Constituyen un problema de salud pública durante los meses de otoño e invierno, con una sobredemanda de atención en los servicios de urgencia y requerimiento de camas en los distintos centros hospitalarios, guardando este fenómeno directa relación con la epidemia del virus respiratorio sincicial (VRS), el principal agente etiológicoi-ii. En los últimos años se han implementado una serie de medidas que han permitido desarrollar un mejor manejo de las IRAB, como el uso de nuevos esquemas de vacunación, la disminución del uso irracional de antibióticos, la implementación de salas IRA en atención primaria para el manejo de las infecciones respiratoriasiii, uso de protocolos actualizados para manejo de patología respiratoriaiv, aumento del recurso humano durante la campaña de invierno en los servicios públicos de salud, y avances en infraestructura. Los virus son la principal causa de IRAB, siendo el VRS el más frecuente, seguido por rinovirus, virus influenza, parainfluenza, metapneumovirus, y adenovirus. Éste último, hasta hace algunos años era la segunda causa viral de IRAB, importante agente en infecciones asociadas a la atención en salud y causa de secuelas respiratorias en muchos casosv-vi. Esto pone de manifiesto la importancia de determinar la etiología de las IRAB en pacientes hospitalizados, más cuando la clínica e imagenología no permiten diferenciarlos. Conocer la etiología condicionará medidas terapéuticas a tomar, necesidad de aislamiento, y seguimiento de casos especiales. Esto cobra particular importancia en los lactantes, quienes por presentar un menor desarrollo de la vía respiratoria e inmadurez inmunológica, tienen las más altas tasas de hospitalización y padecen los cuadros más gravesvii. De acuerdo a datos del Departamento de Estadísticas e Información de Salud (DEIS) del año 2011, las infecciones respiratorias fueron la principal causa de egresos hospitalarios de niños y adolescentes en el país con un 21,7% del total. Específicamente en el Hospital Roberto del Rio la situación fue similar, correspondiendo a un 33,3% de las altas. En el siguiente reporte se describen las características de las infecciones respiratorias agudas bajas de niños y adolescentes egresados del Hospital Roberto del Río a lo largo del año 2016.

Lower respiratory tract infections (LRTI) are the main cause of outpatient visits during cold months and hospitalization in infants. Through an observational, descriptive study, we analyzed the medical attentions at the Emergency Department (ED) and the hospitalizations occurred during 2016 in Hospital Roberto del Río. We included demographic variables, date of admission, diagnosis at discharge, etiologic agent and requirement of intensive care unit. Respiratory infections were the main cause of outpatient visits to the ED, being 21.7%. They are also the major cause of hospital discharge (1,856 cases, 23.8% of total). 61% of hospitalized cases were male, ant the mail affected group was those under 2 years of age (74.4%). In 93% of cases with detected etiological agent, a virus was found, 57, 9% being respiratory syncytial virus. Sixty nine percent of admission occurred during June and September and 15, 2% patients were admitted to the intensive care unit. We hope the current data helps policy maker in further years.

SP-A1, SP-A2 and SP-D gene polymorphisms in severe acute respiratory syncytial infection in Chilean infants.

Respiratory syncytial virus (RSV) is the principal pathogen that causes acute lower respiratory tract infection (ALRI) in infants. Severe RSV-ALRI has been associated with the host genetic susceptibility. To assess whether severe RSV disease in infants is associated with certain single nucleotide polymorphism (SNP) into the gene of SP-A1, SP-A2 and SP-D, a prospective study was performed among blood donors and RSV-infected infants aged

Impaired immune response in severe human lower tract respiratory infection by respiratory syncytial virus.

BACKGROUND: Respiratory syncytial virus (RSV) is a major cause of acute lower respiratory infection in infants. The immune response plays a leading role in the severity of the disease. We hypothesized that severe RSV disease is associated with an impaired immune response characterized by low circulating T lymphocytes and plasma cytokine concentrations. METHODS: We evaluate the in vivo immune responses of previously healthy infants with their first proven RSV-acute lower respiratory infection that required hospitalization. According to the clinical severity, defined by using a strict scoring system, the in vivo immune response was compared through the analysis of plasma cytokine values and the phenotyping of peripheral blood lymphocyte and natural killer (NK) cells. RESULTS: Absolute blood cell counts of CD4+, CD8+, and CD19+ lymphocytes and NK cells were lower in subjects with RSV than in control infants. Lowest cell counts were observed in more severe RSV-infected infants. Significant low values were obtained in CD8+ lymphocytes (P = 0.03) and nonactive NK cells, that express CD94 antigen (P = 0.046). In contrast, activated NK cells that do not express CD94 molecules were significantly higher in RSV infected infants than in healthy controls (% of cells: P = 0.004). The interferon-gamma and tumor necrosis factor-alpha values in RSV infected patients were lower than in controls subjects. Interleukin-17 cytokine was not detected in healthy infants and the largest concentration was found in moderately ill patients as compared with severe cases (P = 0.033). RSV infection showed significantly higher interleukin-8 chemokine than in control infants (P = 0.024). CONCLUSION: We propose that severe RSV infection in very young infants is associated with poor blood proinflammatory cytokine production, low counts of CD8+ T cells and with a greater activity of a group of NK cells, that are independent of the major histocompatibility complex class Ib recognition system.

Management of infants with chronic lung disease of prematurity in Chile.

Despite advances in the prevention and management of respiratory distress syndrome, chronic lung disease of prematurity (CLD) remains a major cause of morbidity and mortality in preterm babies in Chile. Its incidence varies from 10% to 60% in different regions of Chile. Since 1998, the management of CLD after discharge from neonatal unit follows national guidelines. Target oxygen saturation is 85% to 91% in the first 1 week of life, 91% to 94% from 1 to 2 weeks and over 95% after 44 weeks postconceptional age. National home oxygen program has improved outcome in infants with CLD. Other specific treatments are used with caution. Diuretics are used for pulmonary oedema. The adverse neurological outcome in infants treated with postnatal steroids restricts its use to infants who cannot be weaned from mechanical ventilation. Inhaled steroids and bronchodilators may reduce asthma-like symptoms in established CLD. Prevention of RSV infection in CLD babies is paramount. The preterm infant population has been maintained under surveillance nationally since 1998.

Adenovirus and respiratory syncytial virus-adenovirus mixed acute lower respiratory infections in Chilean infants.

BACKGROUND: In Chile respiratory syncytial virus (RSV) and adenovirus (AD) are the principal viruses detected in acute lower respiratory infections (ALRI) in infants. An overview of AD pneumonia in Chile to detect annual trends and to compare the severity of single AD or mixed RSV-AD infections is presented. METHODS: Surveillance in 4927 infants hospitalized for ALRI has been performed from 1989 to 2001 using immunofluorescence assay (IFA) and viral isolation. Clinical features in 117 infants with single genotyped AD and 81 infants with mixed RSV-AD infections were analyzed. RESULTS: Adenovirus cases declined from 20% annually in the early 1990s to approximately 5% in the 2000 decade. Genotype 7h showed increasing prevalence in hospitalized cases. The mean annual burden of hospitalizations caused by AD in Santiago was estimated to be 0.6%. No difference was observed in duration of fever, oxygen requirement and hospital stay between groups. Lung consolidation was more frequent in AD cases than mixed cases (P < 0.01); interstitial pattern and hyperinflation prevailed in the mixed cases (P < 0.01). No child died. AD diagnosis was confirmed on admission by IFA in 17% of cases of RSV-AD and in 43% of cases of single AD ALRI. AD cases diagnosed early by IFA had worse clinical outcome than those diagnosed later by virus isolation (P < 0.05). CONCLUSIONS: AD cases declined since 1989. Mixed RSV-AD infections were not more severe than single AD etiology. AD cases admitted with positive IFA had worse prognoses than AD infections diagnosed later by virus isolation.

[The influence of winter 2002 in pediatric health: dissociation between environmental factors and respiratory syncytial viruses, in Santiago]. / Impacto en salud infantil del invierno 2002: disociación entre factores ambientales y virus respiratorio sincicial, en Santiago.

BACKGROUND: The increase in winter related health pediatric demand is associated with three factors: cold and rainy weather, air pollution and respiratory viral epidemics. During the winter of 2002 there was, successively, heavy rain, air pollution, cold weather and a respiratory syncytial virus (RSV) epidemic in Santiago. AIM: To study the influence of environmental factors and RSV epidemic on pediatric health care demand. PATIENTS AND METHODS: The number of hospital admissions and outpatient consultations for acute lower respiratory infections (ALRI) from April to October 2002 (Autumn to Spring in Chile), were registered in a public pediatric hospital of Santiago. A respiratory virus surveillance (RSV, adenovirus influenza and parainfluenza virus) was carried out among children admitted for ALRI. Climate conditions and air pollution (number of particles of more than 10 microns/mm3) values were provided by local environmental health services. RESULTS: As expected, a rise in winter hospital admissions and outpatient consultations was detected, that peaked in week 29. This rise coincided with the higher RSV detection week. There was heavy rain in weeks 22, 23 and 30, as well as cold weather in June-July (weeks 23, 24, 26, 27 and 30; mid Winter), that did not increase health care demand. Likewise, high air pollution, registered from weeks 24 to 26, did not increase health care demand. CONCLUSIONS: RSV epidemic is the principal factor associated to the increase in health burden during winter in Santiago.

Surveillance for respiratory syncytial virus in infants hospitalized for acute lower respiratory infection in Chile (1989 to 2000).

Hospitalized infants (4,618) were studied for lower respiratory infections from 1989 through 2000 by routine immunofluorescence assay and viral isolation. The hospitalization rate for respiratory syncytial virus (RSV) averaged 2% per year. The fatality rate was 0.1%. Monthly RSV detection varied from 14 to 88%, and epidemics lasted 3.5 to 6 months. From 1994 high-early versus low-late epidemic patterns alternately were observed, the first influenced by a group B strain.