Epidemiological surveillance and influence of co-infection by respiratory viruses in the severity of acute bronchiolitis in infants <b>[Abstract in English]<\b>

Abstract

Aims: To evaluate the epidemiologic characteristics and to compare the seriousness of the infection between one or more than one viral agents in infants hospitalized with acute viral bronchiolitis. Methods: A cross-sectional study conducted between September 2009 and September 2010 included infants up to 12 months of age diagnosed with acute viral bronchiolitis, who were admitted to the pediatric units of the Hospital São Lucas da PUCRS and had started with lower airways symptoms to 72 hours before inclusion. Testing for respiratory viruses was performed on nasopharyngeal specimens by direct immunofluorescence. Results: Seventy one samples were collected from a total of 73 patients, whose mean age was 3.3 months. Of the total samples collected, 61,97% (44/71) were positive for virus. Of these, 70,46% (31/44) were positive for one virus and 29,54% (13/44) for two or more viruses. Respiratory syncytial virus was the most common (86,36%), followed by parainfluenza (27,27%). Using the outcomes length of hospital stay and time of use of oxygen, there was no association between the presence of coinfection and severity of bronchiolitis. Conclusions: The study demonstrated a high overall positivity for viruses, with the predominance of respiratory syncytial virus. A high rate of viral coinfection was also showed. There was no additional effect of the presence of more than one type of virus on the severity of bronchiolitis. We can not exclude the possibility that the combination with other viruses, unidentified in this study, may influence the severity of acute viral bronchiolitis