EPIDEMIOLOGY: Adenovirus is of worldwide prevalence, and is ubiquitous throughout the year, especially during later winter and early spring. Serotype 5 is the most common, with serotypes 1 and 2 being highly endemic. Children are especially susceptible to infection. Adenovirus serotypes 3, 4, 7, and 21 have been associated with outbreaks of acute respiratory disease among military recruits. These outbreaks have resulted in hospitalization and some mortality.