Abrupt emergence of diverse species B adenoviruses at US military recruit training centers

Background. Adenoviruses (Ads) cause continuous outbreaks of acute respiratory disease (ARD) in US military training facilities. In 1996, the loss of vaccines targeting the dominant recruit- associated serotypes precipitated the reemergence of Ads in these populations. Between 1999 and 2002, serotype 4 accounted for >95% of Ads isolated from recruits and for >50% of ARD cases in training facilities (15,000 cases/year). Methods. Ads (n = 1867) collected between 2002 and 2006 from recruits with ARD at 8 military training facilities in the United States were serotyped by serum neutralization and polymerase chain reaction. Results. The dominance of Ad4 continued through 2005, followed by a simultaneous emergence of diverse species B serotypes at the majority of sites. This included the subspecies B1 serotypes 3, 7, and 21 and the subspecies B2 serotype 14. Ad14 was the most prevalent species B serotype, appearing in high numbers at 3 sites and becoming dominant at 1. Conclusions. Subspecies B2 Ads have rarely been associated with ARD, and only in Eurasia. This survey represents the first report of AdB2- associated ARD in the Western Hemisphere. The simultaneous emergence of several species B Ads suggests a common external source (the civilian population) and a decrease in preexisting immunity to species B Ads.