Sixteen years of evolution of human respiratory syncytial virus subgroup A in Buenos Aires, Argentina: GA2 the prevalent genotype through the years

Human respiratory syncytial virus (HRSV) is the main viral cause of acute lower respiratory tract infections (LRTI) in children worldwide. In recent years, several preclinical trials with vaccine candidates have been reported. It is in this sense that molecular epidemiological studies become important. Understanding viral dispersion patterns before and after the implementation of a vaccine can provide insight into the effectiveness of the control strategies. In this work we analyzed the molecular epidemiology of HRSV-A over a period of sixteen years (1999-2014) in Buenos Aires. By bioinformatic tools we analyzed 169 sequences of the G glycoprotein gene from hospitalized pediatric patients with LRTI. We found that GA2 was the most prevalent genotype (73.35%). GA5 genotype co-circulated in our region until 2009 when it was no longer detected, except in 2011. The recently globally emerging ON1 lineage with a 72-nt duplication increased its frequency to become the only lineage detected in Buenos Aires in 2014. By discrete phylogeographic analysis of global ON1 strains we could determine that Panama could be the location of the MRCA dated June 20, 2010; and this lineage could be introduced in Argentina from Spain in April 2011. This analysis also showed temporary and geographical clustering of ON1 strains observed as phylogenetic clades with strains exclusively associated from a single country, nevertheless among our 44 ON1 strains from three outbreaks (2012-2014) we could also detect posterior reintroductions and circulation from United States, Cuba, South Korea, and Spain. The continuous phylogeographic analysis of one sublineage of Argentine ON1 strains allowed us to establish that there could be a local clustering of some strains even in neighborhoods. This work shows the potential of this type of bioinformatic tools in the context of a future vaccine surveillance network to trace the spread of new genetic lineages in human populations.Fil: Viegas, Mariana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Goya, Stephanie. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; ArgentinaFil: Mistchenko, Alicia Susana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; Argentin

Secondary infections of the dengue virus in Buenos Aires metropolitan area

El alto porcentaje de infecciones secundarias detectado en un área no endémica podría estar indicando la posible circulación críptica del virus, siendo ésta causante de infecciones inaparentes. Considerando que en el área metropolitana de Buenos Aires (AMBA) se detectó transmisión local de dengue por primera vez durante el brote de 2009, es destacable el hecho de que durante dicho año más del 20% de las muestras analizadas resultaron ser infecciones secundarias.Fil: Tittarelli, Estefanía. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Barrero, Paola Roxana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Mistchenko, Alicia Susana. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Valinotto, Laura Elena. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

RSV reemergence in Argentina since the SARS-CoV-2 pandemic

Introduction: The community mitigation measures taken because of the COVID-19 pandemic had side effects on the circulation of the most frequent respiratory viruses during 2020. In the case of respiratory syncytial virus (RSV), an important paediatric pathogen, a decrease in the number of cases and delayed outbreaks was previously described. Aim and Methods: The genetic characteristics of the RSV circulating strains in paediatric patients in Buenos Aires, Argentina before and during the COVID-19 pandemic were studied. RSV (+) samples taken from hospitalised patients with respiratory tract infections (2018- 2021) were analysed through G gene sequencing and evolutionary analyses. Results: No RSV hospitalised paediatric patients were registered in Buenos Aires during 2020; however, RSV reemerged in 2021 with a lower number of cases and a delayed outbreak, peaking in July-August. A total of 147 G gene sequences were analysed. RSV-B (N = 85) predominated during 2018 and 2021 whereas in 2019 RSV-A were more prevalent (N = 62). All RSV-A sequences were ON1-like strains, and all RSV-B were BA-like. Phylogenetic analyses showed that the same genetic lineages circulated before and after 2020, but RSVs from 2021 corresponded to new viral introductions rather than cryptic circulation of the previous genetic clusters in Buenos Aires during 2020. Conclusions: Following the reopening of borders, the reemergence of RSV in Argentina brought new viral introductions from other countries. Therefore, it is important to continue a deep global molecular surveillance to characterise RSV strains in post-pandemic circulation with an impact in future vaccine implementation.Fil: Acuña, Dolores. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Goya, Stephanie. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nabaes Jodar, Mercedes Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; ArgentinaFil: Grandis, Érica. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; ArgentinaFil: Mistchenko, Alicia Susana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Viegas, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; Argentin

Respiratory syncytial virus: Clinical and epidemiological pattern in pediatric patients admitted to a children’s hospital between 2000 and 2013

INTRODUCTION: Respiratory syncytial virus (RSV) is the major causative organism associated with acute lower respiratory tract infections in children.The objective of this study was to describe the clinical and epidemiological pattern of RSV and identify risk factors for RSV infection. POPULATION AND METHODS: Prospective, cohort study on patients hospitalized due to acute lower respiratory tract infection at Hospital de Niños Ricardo Gutiérrez between March and November throughout the 2000-2013 period. The virological diagnosis of RSV, adenovirus, influenza and parainfluenza was performed by indirect immunofluorescence using nasopharyngeal aspirates. RESULTS: A total of 12,555 children were included, 38.2% (4798) had virus rescued from samples. RSV accounted for 81.8% of cases (3924/4798) with no significant annual variations (71.2- 88.1) and with an epidemic seasonal pattern(May through July); RSV was followed by influenza (7.6%), parainfluenza (5.9%), and adenovirus (4.7%).The median age of patients with RSV rescue (3924) was 7 months old (0- 214 months old), while 74.2% were younger than 1 year old, 43.1% were younger than 6 months old, 56.5% were males and the most common clinical presentation was bronchiolitis (60.7%). Comorbidities were observed in 41.6% of cases. The most common comorbidities were chronic respiratory disease (74%), congenital heart disease (14%), and chronic neurological disease (10.2%).Complications occurred in 25%of cases. The case fatality rate was 1.9% (74/3888). Independent predictors of RSV infection were age <3 months old (OR: 2.8 [2.14-3.67], p < 0.01),clinical presentation of bronchiolitis (OR: 1.54 [1.32-1.79], p < 0.01), and hypoxemia at the time of admission (OR: 1.84 [1.42-2.37], p < 0.01). CONCLUSIONS: RSV infection displayed a seasonal pattern and was associated with infants younger than 3 months old with bronchiolitis and hypoxemia at the time of admission.Fil: Lucion, María Florencia. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Juárez, María del Valle. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Viegas, Mariana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Castellano, Verónica. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Romanin, Viviana Sandra. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Grobaporto, Marcela. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Bakir, Julia. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Mistchenko, Alicia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; ArgentinaFil: Gentile, Ángela. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentin

Infección sintomática por citomegalovirus a través de la lactancia materna en un niño de 45 días

La infección posnatal o adquirida por citomegalovirus en el recién nacido se transmite por secreciones cervicales maternas en el parto, lactancia materna o transfusión de hemoderivados. La leche materna es la principal fuente de infección. Las manifestaciones clínicas dependen de la edad gestacional y el peso de nacimiento. Son más vulnerables los nacidos prematuros y de bajo peso. La infección posnatal, generalmente, es asintomática y suele resolverse de manera espontánea sin necesidad de tratamiento antiviral; el riesgo de secuelas a largo plazo es menor que en la infección congénita. Describimos el caso de un niño de 45 días de vida, nacido de término con peso adecuado para su edad gestacional, con un cuadro clínico muy poco frecuente caracterizado por plaquetopenia grave, secundario a una infección posnatal por citomegalovirus. Detallamos su forma de presentación, evolución clínica, diagnóstico y la terapéutica empleada.Postnatal infection or acquired cytomegalovirus in the newborn is transmitted by maternal cervical secretions at birth, breastfeeding, blood transfusion or biological fluids. Breast milk is the main source of infection. Clinical manifestations depend on the gestational age and birth weight, premature and low birth weight newborn being more vulnerable. Postnatal infection usually resolves spontaneously without antiviral treatment; the risk of long-term sequelae is lower than in congenital infection. We describe the case of a 45 days old male patient, term newborn appropriate for gestational age, with a very rare condition characterized by severe thrombocytopenia secondary to postnatal cytomegalovirus infection. We detail its symptoms, clinical evolution, diagnosis and treatment employed

Whole genome sequencing of respiratory syncytial (RSV) virus from clinical samples with low viral load

Here is a description of a protocol for whole genome sequencing of RSV from clinical samples (nasopharyngeal aspirates -NPA-). The protocol was tested with samples with viral loads as low as 10+03 viral copies/ml NPA. The RNA is amplified by RT-PCR in five overlapped fragments of around 2300-4500 nt in length by using specific primers which anneal in conserved regions of the genome. Briefly the protocol includes: viral RNA extraction from NPA done with silica membrane columns and fragment amplification performed in five independent reaction tubes with OneStep RT-PCR Kit (Qiagen). Each fragment size check performed in an agarose gel electrophoresis, clean-up step done with silica membrane columns and the quantification step performed by Qubit. Finally, amplicons pooled equimolarly and library prep done with Nextera XT Kit.Fil: Goya, Stephanie. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rojo, Gabriel Lihue. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nabaes Jodar, Mercedes Soledad. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Valinotto, Laura Elena. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mistchenko, Alicia Susana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; ArgentinaFil: Viegas, Mariana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Toward unified molecular surveillance of RSV: A proposal for genotype definition

Background: Human respiratory syncytial virus (RSV) is classified into antigenic subgroups A and B. Thirteen genotypes have been defined for RSV-A and 20 for RSV-B, without any consensus on genotype definition. Methods: We evaluated clustering of RSV sequences published in GenBank until February 2018 to define genotypes by using maximum likelihood and Bayesian phylogenetic analyses and average p-distances. Results: We compared the patterns of sequence clustering of complete genomes; the three surface glycoproteins genes (SH, G, and F, single and concatenated); the ectodomain and the 2nd hypervariable region of G gene. Although complete genome analysis achieved the best resolution, the F, G, and G-ectodomain phylogenies showed similar topologies with statistical support comparable to complete genome. Based on the widespread geographic representation and large number of available G-ectodomain sequences, this region was chosen as the minimum region suitable for RSV genotyping. A genotype was defined as a monophyletic cluster of sequences with high statistical support (≥80% bootstrap and ≥0.8 posterior probability), with an intragenotype p-distance ≤0.03 for both subgroups and an intergenotype p-distance ≥0.09 for RSV-A and ≥0.05 for RSV-B. In this work, the number of genotypes was reduced from 13 to three for RSV-A (GA1-GA3) and from 20 to seven for RSV-B (GB1-GB7). Within these, two additional levels of classification were defined: subgenotypes and lineages. Signature amino acid substitutions to complement this classification were also identified. Conclusions: We propose an objective protocol for RSV genotyping suitable for adoption as an international standard to support the global expansion of RSV molecular surveillance.Fil: Goya, Stephanie. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Galiano, Mónica. Public Health England; Reino UnidoFil: Nauwelaers, Inne. Imperial College London; Reino UnidoFil: Trento, Alfonsina. Instituto de Investigación Hospital 12 de Octubre; EspañaFil: Openshaw, Peter J.. Imperial College London; Reino UnidoFil: Mistchenko, Alicia Susana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Zambon, Maria. Public Health England; Reino UnidoFil: Viegas, Mariana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Burden of respiratory syncytial virus disease and mortality risk factors in Argentina: 18 years of active surveillance in a children's hospital

Background: Respiratory syncytial virus is the leading cause of acute lower respiratory infection in children. We aimed to describe the clinical-epidemiologic pattern and risk factors for mortality associated with RSV infection. Methods: This is a prospective, cross-sectional study of acute lower respiratory infection in children admitted to the Children’s Hospital during 2000 to 2017. Viral diagnosis was made by fluorescent antibody techniques or real-time-polymerase chain reaction. We compared clinical-epidemiologic characteristics of RSV infection in nonfatal versus fatal cases. Multiple logistic regression was used to identify independent predictors of mortality. Results: Of 15,451 patients with acute lower respiratory infection, 13,033 were tested for respiratory viruses and 5831 (45%) were positive: RSV 81.3% (4738), influenza 7.6% (440), parainfluenza 6.9% (402) and adenovirus 4.3% (251). RSV had a seasonal epidemic pattern coinciding with months of lowest average temperature. RSV cases show a case fatality rate of 1.7% (82/4687). Fatal cases had a higher proportion of prematurity (P < 0.01), perinatal respiratory history (P < 0.01), malnourishment (P < 0.01), congenital heart disease (P < 0.01), chronic neurologic disease (P < 0.01) and pneumonia at clinical presentation (P = 0.014). No significant difference between genders was observed. Most deaths occurred among children who had complications: respiratory distress (80.5%), nosocomial infections (45.7%), sepsis (31.7%) and atelectasis (13.4%). Independent predictors of RSV mortality were moderate-to-severe malnourishment, odds ratio (OR): 3.69 [95% confidence interval (CI): 1.98–6.87; P < 0.0001]; chronic neurologic disease, OR: 4.14 (95% CI: 2.12–8.08; P < 0.0001); congenital heart disease, OR: 4.18 (95% CI: 2.39–7.32; P< 0.0001); and the age less than 6 months, OR: 1.99 (95% CI: 1.24–3.18; P = 0.004). Conclusions: RSV showed an epidemic pattern affecting mostly young children. Malnourishment, chronic neurologic disease, congenital heart disease and the age less than 6 months were the independent risk factors for RSV mortality.Fil: Gentile, Angela. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Lucion, Maria Florencia. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Juarez, Maria del Valle. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Areso, María Soledad. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Bakir, Julia. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Viegas, Mariana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mistchenko, Alicia Susana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez". Laboratorio de Virología; Argentin

An optimized methodology for whole genome sequencing of RNA respiratory viruses from nasopharyngeal aspirates

Over the last decade, the number of viral genome sequences deposited in available databases has grown exponentially. However, sequencing methodology vary widely and many published works have relied on viral enrichment by viral culture or nucleic acid amplification with specific primers rather than through unbiased techniques such as metagenomics. The genome of RNA viruses is highly variable and these enrichment methodologies may be difficult to achieve or may bias the results. In order to obtain genomic sequences of human respiratory syncytial virus (HRSV) from positive nasopharyngeal aspirates diverse methodologies were evaluated and compared. A total of 29 nearly complete and complete viral genomes were obtained. The best performance was achieved with a DNase I treatment to the RNA directly extracted from the nasopharyngeal aspirate (NPA), sequence-independent single-primer amplification (SISPA) and library preparation performed with Nextera XT DNA Library Prep Kit with manual normalization. An average of 633,789 and 1,674,845 filtered reads per library were obtained with MiSeq and NextSeq 500 platforms, respectively. The higher output of NextSeq 500 was accompanied by the increasing of duplicated reads percentage generated during SISPA (from an average of 1.5% duplicated viral reads in MiSeq to an average of 74% in NextSeq 500). HRSV genome recovery was not affected by the presence or absence of duplicated reads but the computational demand during the analysis was increased. Considering that only samples with viral load E+06 copies/ml NPA were tested, no correlation between sample viral loads and number of total filtered reads was observed, nor with the mapped viral reads. The HRSV genomes showed a mean coverage of 98.46% with the best methodology. In addition, genomes of human metapneumovirus (HMPV), human rhinovirus (HRV) and human parainfluenza virus types 1–3 (HPIV1-3) were also obtained with the selected optimal methodology.Fil: Goya, Stephanie. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Valinotto, Laura Elena. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tittarelli, Estefanía. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rojo, Gabriel Lihue. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Nabaes Jodar, Mercedes Soledad. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Greninger, Alexander L.. University of Washington; Estados UnidosFil: Zaiat, Jonathan Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Marti, Marcelo Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mistchenko, Alicia Susana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Viegas, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentin

Nuevos virus respiratorios en niños de 2 meses a 3 años con sibilancias recurrentes

Introducción. Los virus respiratorios son los agentes que con más frecuencia desencadenan sibilancias, especialmente, el virus sincicial respiratorio en los lactantes y los rinovirus en niños mayores. Objetivos. Conocer la prevalencia y la circulación estacional de los virus respiratorios nuevos y tradicionales en lactantes y niños pequeños con sibilancias recurrentes. Material y métodos. Estudio de corte transversal, prospectivo y descriptivo. Se incluyeron pacientes de 2 meses a 3 años con sibilancias recurrentes y factores de riesgo para desarrollar asma hospitalizados por obstrucción bronquial. Se obtuvo una muestra de secreciones respiratorias por aspirado nasofaríngeo y se utilizó la técnica de inmunofluorescencia para detectar Virus Sincicial Respiratorio, Adenovirus, Parainfluenza 1, 2 y 3 e Influenza A y B, y la Reacción en Cadena de la Polimerasa para determinar Rinovirus, Enterovirus, Virus Sincicial Respiratorio, Bocavirus, Adenovirus y Coronavirus. Resultados. Se evaluaron 119 pacientes (61 femeninos), edad (x ± DE) 1,5 ± 0,9 años. Los días de internación y de requerimientos de oxígeno fueron (x ± DE): 6,3 ± 2,9 y 4,4 ± 2,7 respectivamente. Se hallaron 102 (86%) casos positivos. El 55% de los virus se detectó por Inmunofluorescencia y el 45% por Reacción en Cadena de la Polimerasa. El 75% de las muestras respiratorias presentó un solo agente viral, el 22% una coinfección doble y el 3% una coinfección triple. Las prevalencias de los virus respiratorios detectados fueron: Virus Sincicial Respiratorio 55 (43%); Rinovirus 30 (23%); Metapneumovirus 13 (10%); Influenza A 8 (6%), Enterovirus 6 (5%); Bocavirus 6 (5%); Adenovirus 4 (3%); Coronavirus 3 (2%); Parainfluenza 1: 2 (1%); Influenza B, 1 (1%) y Parainfluenza 3: 1 (1%). Conclusiones. Los lactantes y niños pequeños con sibilancias recurrentes hospitalizados por obstrucción bronquial presentan una elevada prevalencia de virus respiratorios. Los picos de internaciones coinciden con los picos de mayor circulación viral.Introduction. Respiratory viruses are associated with respiratory exacerbations, more frequently Respiratory Syncytial Virus in infants and Rhinovirus in children. Objective. To evaluate the prevalence and epidemiological features of newer and traditional respiratory viruses in infants and young children with recurrent wheeze. Material and methods. Cross sectional, prospective and descriptive study. Patients with recurrent wheeze and risk factors for asthma, age 2 months to 3 years, hospitalized with bronchial obstruction were included. On admission a respiratory sample was obtained through a nasopharyngeal aspirate. Immunofluorescence was performed to detect Respiratory Syncytial Virus, Adenovirus, Parainfluenza 1, 2, 3 and Influenza A and B. Polymerase Chain Reaction was used to detect Rhinovirus, Enterovirus, Metapneumovirus, Bocavirus, Adenovirus and Coronavirus. Results. 119 patients (61 female), age (x ± DS) 1.5 ± 0.9 years were included. Days on admission and on oxygen requirement were, respectively (x ± DS): 6.3 ± 2.9 y 4.4 ± 2.7. One hundred and two (86%) positive cases were diagnosed. Fifty five percent of the viruses were detected by Immunofluorescence and 45% by Polymerase Chain Reaction. A single virus was present in 75% of the samples, 22% had a double co-infection and 3% a triple virus co-infection. Overall, the prevalence of detected respiratory viruses was: Respiratory Syncytial Virus 55 (43%); Rhinovirus 30 (23%); Metapneumovirus 13 (10%); Influenza A 8 (6%); Enterovirus 6 (5%); Bocavirus 6 (5%); Adenovirus 4 (3%); Coronavirus 3 (2%); Parainfluenza 1: 2 (1%); Influenza B, 1 (1%) and Parainfluenza 3: 1 (1%). Conclusions. Infants and young children with recurrent wheeze and risk factors for asthma hospitalized for bronchial obstruction present a high prevalence of respiratory viruses. Hospital admissions were more frequent during months of higher respiratory circulation