Human mastadenoviruses (HAdVs) are a common cause of respiratory infections in infants and young children. Infections in humans are caused by ten species, within which more than 100 genotypes and around 67 serotypes are distinguished. HAdVs are the causative agents of various diseases, which are usually asymptomatic. Less commonly, they can cause bronchiolitis, bronchitis, and pneumonia with a more severe course. The authors wanted to determine the frequency of HAdVs occurrence in children with acute bronchiolitis, being particularly interested in whether the detection of HAdV nucleic acid signifies active viral replication and whether there is any correlation between the detection limit of an active virus and the severity of clinical symptoms. Additionally, the researchers aimed to determine which types and genotypes of HAdVs appear in children with acute bronchiolitis and whether specific genotypes are more associated with lower respiratory infections. Our study included nasopharyngeal swabs and stool samples from children admitted to the Clinic for infectious diseases and fever conditions or the Surgery Division of the University Medical Centre in Ljubljana. Real-time PCR with and without reverse transcription were performed. The presence of HAdVs in samples was determined by amplifying a 132 bp segment of the hexon gene. Nucleotide sequencing was performed using a genetic analyzer. Results concluded that more boys than girls were infected. The prevalence of infections was not significantly different between children with acute bronchiolitis and healthy children. Viral DNA was more frequently detected in stool samples; on the contrary, HadVs mRNA was only detected in nasopharyngeal swabs. Inactive adenoviral infections were more common than active ones. We did not determine a correlation between the virus detection limit and the severity of clinical symptoms. However, a lot of children with HAdVs DNA detected in their stool only had pharyngitis. The majority of genotyped HAdVs belonged to type C. Children were often simultaneously infected with several respiratory viruses.
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