Clinical characteristics of adenovirus associated lower respiratory tract infection in children

Background: Acute lower respiratory tract infection (ALRI) due to adenovirus infection is a low frequency event but often causes severe outcome. This study was undertaken to uncover the clinical and epidemiological features of adenovirus infection in children. Methods: Hospitalized children with ALRI were analyzed through continuous monitoring from 2006 to 2012. Nasopharyngeal aspirates were examined by direct immunofluorescence to detect respiratory agents including respiratory syncytial virus, adenovirus, influenza virus types A/B, parainfluenza virus types 1/2/3. Chlamydia pneumonia, Mycoplasma pneumonia and Chlamydia trachomatis were determined by real-time PCR. A retrospective analysis was made of 479 patients with positive infection of adenovirus. Results: The positive detection rate of adenovirus was 0.63% in patients with ALRI. The incidence rate of adenovirus-associated acute lower respiratory tract infection peaked at the second six months of life. The morbidity was much higher in winter, spring and summer than in autumn. Patients with pneumonia accounted for 73.90% of the patients. More than one-third of the patients developed severe pneumonia, whereas no death was found. Features of severe adenovirus-associated lower respiratory tract infection included persistent high fever with serious infective symptoms, and hepatic dysfunction was one of the most common complications. Mixed infection of atypical pathogens was common (18.58%) in this study. Conclusions: Adenovirus is a critical pathogen that can cause severe respiratory infections even in immunocompetent children. Coinfection of adenovirus with atypical pathogens is common. Antibiotic treatment with azithromycin or erythromycin is necessary in patients with mixed infection of atypical pathogens.