Etiology, Seasonality, and Clinical Features of Viral Respiratory Tract Infections in Children Hospitalized With Acute Bronchiolitis: A Single-Center Study

Gökçe, Sule; Kurugöl, Zafer; Koturoglu, Güldane; Çiçek, Candan; Aslan, Asli

Acute bronchiolitis was diagnosed in 316 infants younger than 24 months of age. Overall, at least one respiratory virus was detected in 75% (237/316) of the cases at Ege University Children's Hospital. The results of the incidence of respiratory viruses in infants hospitalized with AB during the study period are shown in Table 3 . RSV was identified in 127 (40.1%) of the 316 infants hospitalized for AB, and RSV was the most common agent. Of the 127 RSV-positive infants, 76 (59.8%) were sole pathogen for RSV and 51 infants had RSV-coinfection, which was responsible for respiratory tract infection. The second prevalent viral agent was rhinovirus, identified in 78 (24.6%) of the subjects, and as a single pathogen in 35 1%) , and quadruple infections in 1/316 (0.3%) were detected. Of the 81 infants with multiple agents, RSV (51 cases) was the most common virus followed by rhinovirus (n = 43, 53%), influenza virus (n = 18, 22.2%), human metapneumovirus (n = 16, 19.7%), PIV (n = 10, 12.3%), adenovirus (n = 16, 19.7%), human bocavirus (n = 13, 16%), parainfluenza virus (n = 10, 12.3%), and human coronavirus (n = 8, 9.8%). Among dual co-infections, the combination of RSV and rhinovirus had the the highest number (n = 15, 22.3%). The age distribution of infants is shown in Figure 1 for RSV, rhinovirus, adenovirus, and dual infections. In particular, most viral agents were identified in children of all months, whereas RSV was detected in infants aged under 6 months (n = 93/127, 73.2%) and in 15.7% (n = 20/127) of the 127 RSV-positive infants aged under 1 year of age, which was the case in most of our patients. The monthly incidence of bronchiolitis in infants due to common respiratory pathogens is shown in Figure 2 . The majority of the cases were admitted to hospital in the winter time with a peak occurring in January, February, and March; detection rates were also high during these months (26.2%, 25.3%, and 17%, respectively). Other respiratory virus epidemics were seen also during the winter season ( Figure 3 ). Fifteen cases infected with parainfluenza virus, adenovirus, and human bocavirus were seen in the summer time.