ABSTRACT
INTRODUCCIÓN: El virus sincitial respiratorio (VSR) es el agente viral más frecuente de infecciones respiratorias agudas bajas (IRAB) en la primera infancia y el mayor responsable de las hospitalizaciones en el período invernal. OBJETIVOS: Describir las características de los brotes de VSR en la Zona Sanitaria VI de la provincia de Buenos Aires, establecer la diversidad de las cepas circulantes y realizar el análisis bioinformático y filogeográfico de las secuencias de la glicoproteína G. MÉTODOS: Se estudió a pacientes pediátricos internados con presentación compatible con IRAB durante dos picos epidémicos (2014-2015) en cuatro hospitales. Se recopilaron datos clínicos, demográficos y socio-sanitarios, y se detectaron patógenos virales en aspirados nasofaríngeos de estos pacientes por inmunofluorescencia (IF), obteniéndose la secuencia del gen de la proteína G en los VSR positivos. RESULTADOS: De 1296 casos estudiados, 317 fueron positivos para algún agente viral. De ellos, 266 (84%) fueron VSR positivos. Se hallaron asociaciones significativas entre las poblaciones positivas y negativas para VSR. Una tendencia al hacinamiento y vivienda precaria en los casos VSR positivos fue reflejada en los estudios filogeográficos. CONCLUSIONES: Los datos de firma molecular permitieron trazar orígenes y vías de diseminación del VSR. Esto ayuda a señalar zonas y situaciones de vulnerabilidad, estableciendo la población primaria blanco de planes de vacunación u otras medidas profilácticas.
INTRODUCTION: The respiratory syncytial virus (RSV) is the most frequent viral agent associated to acute lower respiratory infections (ALRIs) in early childhood, being the main responsible for hospitalizations during winter. OBJECTIVES: To describe the characteristics of RSV outbreaks in the Health Area VI of Buenos Aires Province, to establish the diversity of circulating strains and to perform a bioinformatic and phylogeographic analysis of glycoprotein G sequences. METHODS: Pediatric inpatients with ALRI-compatible x|presentation during two epidemic peaks (2014-2015) were studied in four hospitals. Clinical, demographic and socio-sanitary data were collected, viral pathogens were detected by immunofluorescence (IF), and the sequence of the G protein gene was obtained in the positive RSVs. RESULTS: From 1296 cases, 317 were positive for some viral agent and 266 (84%) out of these were RSV positive. Significant associations were found among the positive and negative populations for RSV. A trend towards overcrowding and precarious housing in positive RSV cases was reflected in phylogeographic studies. CONCLUSIONS: The molecular signature data allowed tracing origins and routes of RSV dissemination. This helps identify areas and situations of vulnerability, establishing the primary target population for vaccination plans or other prophylactic measures.
Subject(s)
Genotype , Molecular Epidemiology , Respiratory Syncytial Viruses , Respiratory Tract InfectionsABSTRACT
Respiratory syncytial virus (RSV) is the main viral cause of hospitalization due to acute lower respiratory tract infections in infants worldwide. Several vaccines against RSV are under research and development, which are about to be approved. We evaluated transmission patterns in different settings to determine age-specific vaccination targets from a viral perspective. We sequenced the G glycoprotein's ectodomain of a constant clinical sampling between two epidemic outbreaks in a limited geographical region and performed phylogeographic analyses. We described a spatio-temporal transmission between local strains, which were originated in the center of the analyzed area and then spread to others. Interestingly, that central area reported the highest population density of the region and also showed overcrowding. This information should be considered by public health systems to evaluate vaccination at all ages in those areas to decrease viral transmission and in lower density populations only susceptible children should be vaccinated.
Subject(s)
Respiratory Syncytial Virus Infections/transmission , Respiratory Syncytial Virus, Human/physiology , Adolescent , Argentina/epidemiology , Child , Child, Preschool , Disease Outbreaks , Female , Humans , Infant , Male , Respiratory Syncytial Virus Infections/epidemiology , Respiratory Syncytial Virus Infections/virology , Respiratory Syncytial Virus, Human/geneticsABSTRACT
In spite of active measles virus (MV) vaccination strategies, reemergence continues to occur, impairing global eradication programs. The immune status against measles was evaluated in 350 vaccinated healthy Argentine children and teenagers who received a single dose of the MV Schwarz strain Lirugen vaccine (Aventis Pasteur). Sera were assessed for immunoglobulin G (IgG) antibodies by a commercial enzyme immunoassay (EIA) (Enzygnost; Behring), an in-house EIA, and neutralization EIA. Results obtained with these methods showed a marked decline in IgG level with increasing age. At 1 to 4 years of age, 84% of children had IgG antibodies above 200 mIU/ml, conventionally accepted as protective levels, whereas only 32% of older children and teenagers had antibody levels exceeding 200 mIU/ml. Moreover, the MV IgG content in the teenage group was significantly lower than the IgG antibody level of the group of younger children (P < 0.0001). In contrast, screening for IgG antibody levels to inactivated tetanus vaccine showed that, on average, 80% of this population was fully protected and that this high level of protection remained through the teenage years. This study suggests that within this population a considerable proportion of individuals had low measles antibody levels that may be insufficient to protect against reinfections or clinical disease.
Subject(s)
Antibodies, Viral/blood , Measles Vaccine/immunology , Measles virus/immunology , Measles/prevention & control , Adolescent , Age Factors , Antibodies, Bacterial/blood , Argentina , Child , Child, Preschool , Female , Humans , Immunoenzyme Techniques , Immunoglobulin G/blood , Infant , Male , Measles Vaccine/administration & dosage , Neutralization Tests , Statistics as Topic , Tetanus Toxoid/immunologyABSTRACT
Analiza que la rabia es una zoonosis endémica con brotes epidémicos en determinadas épocas, considerada como uno de los mayores problemas de Salud Pública en el Ecuador y algunas partes del mundo. La presente investigación es un estudio epidemiológico de la rabia humana en la provincia del Guayas durante los últimos ocho años con la finalidad de contribuir con las instituciones responsables de la salud en el Ecuador, siendo evidente que, un mejor conocimiento de la epidemiología y patogénesis de la enfermedad, es indispensable para la lucha y erradicación de la misma y fundamentalmente implementar un proceso educativo a la población. De acuerdo a los resultados obtenidos podemos establecer que, la rabia humana es una enfermedad endémica letal, que no respeta sexo, edad ni estación del año, producida principalmente por la mordedura de un perro; con la aparición de los primeros síntomas entre los 16 días a 5 meses y un período de estado hasta 23 días. La aparición de nuevos casos se debe a la presencia de factores precipitantes como: el desarrollo desenfrenado de áreas suburbanas, falta de cobertura de vacunación en animales, lo que lleva al aumento de rabia canina y a la irresponsabilidad de las personas que no preveen las consecuencias de la mordedura de un animal...
