Distribution of influenza virus types by age using case-based global surveillance data from twenty-nine countries, 1999-2014.

BACKGROUND: Influenza disease burden varies by age and this has important public health implications. We compared the proportional distribution of different influenza virus types within age strata using surveillance data from twenty-nine countries during 1999-2014 (N=358,796 influenza cases). METHODS: For each virus, we calculated a Relative Illness Ratio (defined as the ratio of the percentage of cases in an age group to the percentage of the country population in the same age group) for young children (0-4 years), older children (5-17 years), young adults (18-39 years), older adults (40-64 years), and the elderly (65+ years). We used random-effects meta-analysis models to obtain summary relative illness ratios (sRIRs), and conducted meta-regression and sub-group analyses to explore causes of between-estimates heterogeneity. RESULTS: The influenza virus with highest sRIR was A(H1N1) for young children, B for older children, A(H1N1)pdm2009 for adults, and (A(H3N2) for the elderly. As expected, considering the diverse nature of the national surveillance datasets included in our analysis, between-estimates heterogeneity was high (I2>90%) for most sRIRs. The variations of countries' geographic, demographic and economic characteristics and the proportion of outpatients among reported influenza cases explained only part of the heterogeneity, suggesting that multiple factors were at play. CONCLUSIONS: These results highlight the importance of presenting burden of disease estimates by age group and virus (sub)type.

The role of rhinovirus in children hospitalized for acute respiratory disease, Santa Fe, Argentina.

Human rhinoviruses (HRVs) were historically considered upper airway pathogens. However, they have recently been proven to cause infections in the lower respiratory tract, resulting in hospitalization of children with pneumonia, bronchiolitis, and chronic pulmonary obstruction. In this report, HRV frequency and seasonality are described together with patient clinical-epidemiological aspects. From a total of 452 surveyed samples, the HRV nucleic acids was detected in 172 (38.1%) and found in every month of the study year. 60% of inpatients with acute respiratory infection (ARI) associated with HRV were under 6 months of age and 31% had a clinical history, being preterm birth and recurrent wheezing the prevailing conditions. The most frequent discharge diagnoses were pneumonia (35.2%), bronchiolitis (32.4%), and bronchitis (12.4%). Fifteen point nine percent of patients required admission into intensive care units. The results obtained in this study demonstrated the association between HRV and children hospitalizations caused by ARI.

[Parotitis and influenza: unusual association during 2017, in Santa Fe, Argentina]. / Parotiditis e influenza: inusual asociación durante 2017, en Santa Fe, Argentina.

BACKGROUND: Parotitis is an acute viral disease characterized by swelling and pain in one or both salivary glands, submaxillary or submental, fever, headache, muscle ache and/or fatigue. AIM: To investigate the occurrence of influenza virus infection in parotitis cases in a population of Santa Fe during 2017 and analyze clinical and epidemiological characteristics of the cases. METHODS: We studied patients with diagnosis of mumps without age restriction, who came for examination from week 26 to the network of clinicians forming the Sentinel Influenza Unit in Santa Fe. RESULTS: Between epidemiological weeks 26 and 44, 22 clinical parotitis cases we enrolled. The influenza virus was detected in 68.2%, influenza A (H3N2) 93%, and influenza B, 7%. The clinical signs of cases were mild, with an average swelling development of 5 days and no complications. 74% presented with influenza-like illness in tandem with parotitis. CONCLUSIONS: This study provides evidence that a proportion of children presenting with parotitis had influenza A(H3N2) virus infection. It is necessary to implement systematic surveillance of parotitis associated with influenza and differential diagnosis even in the absence of respiratory symptoms.

Características clínico-etiológicas de pacientes pediátricos hospitalizados con diagnóstico de bronquiolitis. Ciudad de Santa Fe, Argentina

Introducción: La bronquiolitis constituye una de las principales causas de Infecciones Respiratorias Agudas Bajas en Pediatría, y es responsable de una proporción significativa de hospitalizaciones en lactantes, fundamentalmente, en menores de 1 año. Su diagnóstico es clínico, caracterizado por síntomas y signos de amplio grado de gravedad. Objetivo: Describir las características clínico-etiológicas de casos de bronquiolitis en menores de 1 año, internados en un hospital de niños de la ciudad de Santa Fe, durante un periodo de un año. Materiales y Métodos: Estudio observacional, transversal. Se analizaron datos demográficos, clínicos y de laboratorio de fichas médicas de vigilancia epidemiológica. Las técnicas diagnósticas usadas según el agente viral fueron RT-PCR en tiempo real, PCR-punto final e Inmunofluorescencia Indirecta. Resultados: Sobre un total de 108 casos, 90,7% tuvo de 1 a 6 meses de edad. La mediana de internación fue de 5 días, y el nacimiento prematuro fue la condición médica previa más frecuente. Un 78,7% (85) tuvo diagnóstico viral positivo, siendo Rinovirus (hRV) y Virus Sincicial Respiratorio (VSR) los agentes más prevalentes, tanto en infección única como en coinfección. El tiempo de oxigenoterapia fue mayor en los pacientes más graves (p<0,001). El 32,4% (35) recibió alguna medicación que fue, en mayor frecuencia, antibiótico. Se encontró asociación positiva y significativa entre la edad menor de 3 meses y una hospitalización mayor a 5 días (OR=2,5; IC: 1,1-5,8; p=0,02); y entre un diagnóstico VSR positivo y un cuadro grave (OR: 7,7; IC: 1,95-39,6; p<0,001). Conclusión: Las características y condiciones médicas consideradas por la literatura como factores de riesgo para el padecimiento y la gravedad de una IRAB, fueron halladas con mayor frecuencia en la población de estudio. El hRV y el VRS fueron los agentes de mayor rescate viral, encontrándose una asociación positiva entre la infección por VSR y la gravedad del cuadro.

Introduction: Bronchiolitis is one of the main causes of Acute Lower Respiratory Infections in pediatrics, and is responsible for a significant proportion of hospitalizations in infants, mainly in children under 1 year of age. Its diagnosis is clinical. The disease is characterized by a wide variety and degree of signs and symptoms. Objective: To describe the clinical-etiological characteristics of cases of bronchiolitis in children under 1 year of age, admitted to a children's hospital in the city of Santa Fe, over a period of one year. Materials and Methods: This was an observational and cross-sectional study. Demographic, clinical and laboratory data from epidemiological surveillance medical records were analyzed. The diagnostic techniques used, based on the viral agent, were real-time RT-PCR, end-point PCR and Indirect Immunofluorescence. Results: Out of a total of 108 cases, 90.7% were between 1 and 6 months old. The median hospital stay was 5 days, and premature birth was the most common prior medical condition. 78.7% (85) had a positive viral diagnosis, with Rhinovirus (hRV) and Respiratory Syncytial Virus (RSV) being the most prevalent agents, both in single infection and coinfection. Oxygen therapy time was longer in the most seriously ill patients (p<0.001). 32.4% (35) received some medication, which was, most frequently, antibiotics. A positive and significant association was found between age less than 3 months and hospitalization longer than 5 days (OR=2.5; CI: 1.1-5.8; p=0.02); and between a positive RSV diagnosis and a severe condition (OR: 7.7; CI: 1.95-39.6; p<0.001). Conclusions: The characteristics and medical conditions considered by the literature as risk factors for the morbidity and severity of a lower respiratory tract infection were found more frequently in the study population. hRV and RSV were the most commonly-detected viral agents. We found a positive association between RSV infection and the severity of the condition.

Characteristics of seasonal influenza A and B in Latin America: Influenza surveillance data from ten countries.

INTRODUCTION: The increased availability of influenza surveillance data in recent years justifies an actual and more complete overview of influenza epidemiology in Latin America. We compared the influenza surveillance systems and assessed the epidemiology of influenza A and B, including the spatio-temporal patterns of influenza epidemics, in ten countries and sub-national regions in Latin America. METHODS: We aggregated the data by year and country and characteristics of eighty-two years were analysed. We calculated the median proportion of laboratory-confirmed influenza cases caused by each virus strain, and compared the timing and amplitude of the primary and secondary peaks between countries. RESULTS: 37,087 influenza cases were reported during 2004-2012. Influenza A and B accounted for a median of 79% and, respectively, 21% of cases in a year. The percentage of influenza A cases that were subtyped was 82.5%; for influenza B, 15.6% of cases were characterized. Influenza A and B were dominant in seventy-five (91%) and seven (9%) years, respectively. In half (51%) of the influenza A years, influenza A(H3N2) was dominant, followed by influenza A(H1N1)pdm2009 (41%) and pre-pandemic A(H1N1) (8%). The primary peak of influenza activity was in June-September in temperate climate countries, with little or no secondary peak. Tropical climate countries had smaller primary peaks taking place in different months and frequently detectable secondary peaks. CONCLUSIONS: We found that good influenza surveillance data exists in Latin America, although improvements can still be made (e.g. a better characterization of influenza B specimens); that influenza B plays a considerable role in the seasonal influenza burden; and that there is substantial heterogeneity of spatio-temporal patterns of influenza epidemics. To improve the effectiveness of influenza control measures in Latin America, tropical climate countries may need to develop innovative prevention strategies specifically tailored to the spatio-temporal patterns of influenza in this region.

[Detection of human bocavirus in children from Tucuman and Santa Fe, Argentina]. / Detección de bocavirus humano en la población infantil de Tucumán y Santa Fe, Argentina.

BACKGROUND: A large proportion of acute respiratory tract infections (ARTI) remain without etiologic diagnosis, reason why new pathogens are investigated continuously. Human bocavirus (HBoV) was discovered in 2005, as a new member of Parvoviridae family and proposed to cause ARTI. AIM: To know the prevalence of HBoV among pediatric populations hospitalized for ARTI in two provinces of Argentina: Santa Fe and Tucuman; and to describe epidemiological and clinical aspects associated to its detection. MATERIALS AND METHODS: We studied nasopharyn-geal aspirates of patients younger than 5 years old that were hospitalized during 2013 due ARTI. HBoV DNA was assayed using PCR described by Allander et al. Traditional virnses were studied by immunofluorescence. Personal, clinical and epidemiological data were collected in a standardized form. RESULTS: The HBoV was detected in 7% of the samples and was prevalent in spring and summer and in children younger of 2 years old. Other respiratory viruses were detected in 22% of HBoV positive samples. DISCUSSION: We detected HBoV in these two provinces of Argentina. Further studies should be performed to determine if it's a recent infection or prolonged viral shedding.

Temporal Patterns of Influenza A and B in Tropical and Temperate Countries: What Are the Lessons for Influenza Vaccination?

INTRODUCTION: Determining the optimal time to vaccinate is important for influenza vaccination programmes. Here, we assessed the temporal characteristics of influenza epidemics in the Northern and Southern hemispheres and in the tropics, and discuss their implications for vaccination programmes. METHODS: This was a retrospective analysis of surveillance data between 2000 and 2014 from the Global Influenza B Study database. The seasonal peak of influenza was defined as the week with the most reported cases (overall, A, and B) in the season. The duration of seasonal activity was assessed using the maximum proportion of influenza cases during three consecutive months and the minimum number of months with ≥80% of cases in the season. We also assessed whether co-circulation of A and B virus types affected the duration of influenza epidemics. RESULTS: 212 influenza seasons and 571,907 cases were included from 30 countries. In tropical countries, the seasonal influenza activity lasted longer and the peaks of influenza A and B coincided less frequently than in temperate countries. Temporal characteristics of influenza epidemics were heterogeneous in the tropics, with distinct seasonal epidemics observed only in some countries. Seasons with co-circulation of influenza A and B were longer than influenza A seasons, especially in the tropics. DISCUSSION: Our findings show that influenza seasonality is less well defined in the tropics than in temperate regions. This has important implications for vaccination programmes in these countries. High-quality influenza surveillance systems are needed in the tropics to enable decisions about when to vaccinate.

Parotiditis e influenza: inusual asociación durante 2017, en Santa Fe, Argentina / Parotitis and influenza: unusual association during 2017, in Santa Fe, Argentina

Resumen Introducción: La parotiditis es una enfermedad vírica aguda caracterizada por tumefacción y dolor en una o ambas glándulas salivales, submaxilar o submentoniana, fiebre, dolor de cabeza, dolor muscular y/o fatiga. Objetivos Investigar la ocurrencia de infección por el virus influenza en casos de parotiditis en una población de Santa Fe, durante 2017 y analizar las características clínicas y epidemiológicas de los casos. Materiales y Métodos: Se estudiaron pacientes con diagnóstico de parotiditis, que acudieron a la consulta desde la semana 26 en la red de médicos que forman la Unidad Centinela de Influenza en Santa Fe. Resultados: Entre las semanas epidemiológicas 26 y 44, se incluyeron 22 casos de parotiditis clínica. El virus influenza se detectó en 68,2%, influenza A (H3N2) 93% e influenza B 7%. Los síntomas clínicos de los casos fueron leves, con una tumefacción de cinco días y sin complicaciones. El 74% presentó una enfermedad tipo influenza en conjunto con la parotiditis. Conclusiones: Este estudio evidencia que niños que presentaban parotiditis tenían una infección por el virus de la influenza A (H3N2). Es necesario implementar una vigilancia sistemática de las parotiditis asociadas con influenza y el diagnóstico diferencial, incluso en ausencia de síntomas respiratorios.

Background: Parotitis is an acute viral disease characterized by swelling and pain in one or both salivary glands, submaxillary or submental, fever, headache, muscle ache and/or fatigue. Aim: To investigate the occurrence of influenza virus infection in parotitis cases in a population of Santa Fe during 2017 and analyze clinical and epidemiological characteristics of the cases. Methods: We studied patients with diagnosis of mumps without age restriction, who came for examination from week 26 to the network of clinicians forming the Sentinel Influenza Unit in Santa Fe. Results: Between epidemiological weeks 26 and 44, 22 clinical parotitis cases we enrolled. The influenza virus was detected in 68.2%, influenza A (H3N2) 93%, and influenza B, 7%. The clinical signs of cases were mild, with an average swelling development of 5 days and no complications. 74% presented with influenza-like illness in tandem with parotitis. Conclusions: This study provides evidence that a proportion of children presenting with parotitis had influenza A(H3N2) virus infection. It is necessary to implement systematic surveillance of parotitis associated with influenza and differential diagnosis even in the absence of respiratory symptoms.

Detección de bocavirus humano en la población infantil de Tucumán y Santa Fe, Argentina / Detection of human bocavirus in children from Tucuman and Santa Fe, Argentina

Background: A large proportion of acute respiratory tract infections (ARTI) remain without etiologic diagnosis, reason why new pathogens are investigated continuously. Human bocavirus (HBoV) was discovered in 2005, as a new member of Parvoviridae family and proposed to cause ARTI. Aim: To know the prevalence of HBoV among pediatric populations hospitalized for ARTI in two provinces of Argentina: Santa Fe and Tucuman; and to describe epidemiological and clinical aspects associated to its detection. Materials and Methods: We studied nasopharyn-geal aspirates of patients younger than 5 years old that were hospitalized during 2013 due ARTI. HBoV DNA was assayed using PCR described by Allander et al. Traditional virnses were studied by immunofluorescence. Personal, clinical and epidemiological data were collected in a standardized form. Results: The HBoV was detected in 7% of the samples and was prevalent in spring and summer and in children younger of 2 years old. Other respiratory viruses were detected in 22% of HBoV positive samples. Discussion: We detected HBoV in these two provinces of Argentina. Further studies should be performed to determine if it’s a recent infection or prolonged viral shedding.

Introducción: Un alto porcentaje de las infecciones respiratorias agudas (IRA) permanece sin diagnostico etiológico, por lo cual se investigan nuevos patógenos continuamente. Bocavirus humano (HBoV) fue descubierto en 2005, como un nuevo miembro de la familia Parvoviridae y propuesto como causante de IRA. Objetivos: Investigar la prevalencia de HBoV en niños bajo 5 años de edad, hospitalizados por IRA en dos provincias de Argentina: Santa Fe y Tucumán y describir aspectos epidemiológicos y clínicos asociados a su detección. Materiales y Métodos: Se estudiaron retrospectivamente los aspirados nasofaríngeos (ANF) de pacientes bajo 5 años de edad, con diagnóstico de IRA, hospitalizados durante el año 2013. La presencia de HBoV se detectó mediante la RPC de punto final descripta por Allander y cols. Los virus tradicionales se estudiaron mediante inmunofluorescencia. Datos personales, clínicos y epidemiológicos se recolectaron en una planilla estandarizada. Resultados: HBoV fue detectado en 7% de las muestras con prevalencia en primavera y verano; y principalmente en pacientes bajo 2 años de edad. Se registró co-detecciones en 22% de los casos. Discusión: Hemos detectado HBoV en estas dos provincias de Argentina; estudios posteriores deberán efectuarse para determinar si se trata de una infección reciente o una excreción prolongada del virus.