Rhinoviruses as critical agents in severe bronchiolitis in infants

Abstract

Objectives: To detect RSV or other thirteen respiratory viruses as possible causer agent of bronchiolitis in infants.

Method: This is an epidemiological analytical study, conducted using a nasopharyngeal aspirate of 173 hospitalized children younger than two years old with severe bronchiolitis in three hospitals in the Campinas Metropolitan Region (CMR) during 2013-14. The data was statically evaluated by Pearson's chi-squared test with statistical significance of 0.05 and 95% confidence level.

Results: As expected, the most prevalent viruses detected were RSV A and B in 47% and 16% of the samples, respectively. However, almost a third of severe bronchiolitis cases there were no detection of RSV, and the viruses more commonly detected were rhinoviruses, which were identified in almost a quarter of all positive samples for at least a viral agent.

Conclusions: Although nothing could be concluded from the disease severity and clinical-epidemiological data, the present study's results indicate that severe bronchiolitis is not always related to RSV infections in children younger than two years old, and the rhinoviruses were more prevalent in these cases. These findings reinforce the need to carry out a viral diagnosis in the hospital emergency would be very appropriate for all cases of respiratory infections in children, even for diseases in which the primary etiological agent seems to be well known.

Keywords: Bronchiolitis; Epidemiology; Respiratory syncytial virus; Rhinovirus.

Figure 1

Distribution of acute respiratory infections (ARI) (n) by months of 173 children younger than two years old with bronchiolitis hospitalized in three different hospitals (107, 43 and 23 from UNICAMP Clinical, Vera Cruz and Sumaré State Hospitals respectively) in 2013 and 2014 from Campinas Metropolitan Region, São Paulo State, Brazil.

Figure 2

Agarose gel image (2%) highlighting the viewing standard of the results. Molecular Weight Marker (MB) corresponds to the pattern used in set B to identify 5 different species of viruses. In this case, 4 positive samples for RV A/B/C (159, 162, 166 and 167), 5 positive samples for RSV A (158, 161, 163, 164 and 165) and 2 positive samples for RSV B (160 and 166). Note: the sample 166 presented co-detection with RV A/B/C and RSV B.