Acute lower respiratory tract infections by adenovirus in children: histopathologic findings in 18 fatal cases.

Adenoviruses (Ads) are the 2nd-most common cause of acute lower respiratory tract infections of viral etiology in immunocompetent children who require hospitalization in Argentina. A new pathogenic genomic variant, Ad7h, has been identified and was associated with severe sequelae and a high mortality rate. A retrospective observational study was conducted in hospitalized children with acute lower respiratory tract infections between March 1988 and May 2005. Nasopharyngeal or tracheal aspirates, bacteriological analysis on blood samples and pleural fluids, and histopathologic studies on autopsies were performed. A total of 415 children were included in the study. Sixty-two patients died in the acute stage of illness (1-8 weeks), and postmortem examination was performed on 18 of them. Mean age was 8.25 months. The male to female ratio was 1.3∶1. The Ad was genome typed in 9% of all children, of whom 29 corresponded to the Ad7h variant. This genome type was diagnosed in 7 of the autopsies performed. Necrotizing bronchitis and bronchiolitis with abundant typical adenoviral inclusion nuclear cells and diffuse alveolar damage were the most important findings. Superimposed bacterial infection occurred in 11 cases, and cytomegalovirus was found in 1. In our population, Ad respiratory infection was found to have a severe course with sequelae or death. No differences were observed between lesions caused by other previously described genome types and those found in cases in which Ad7h was identified.