Molecular Epidemiology and Brief History of Emerging Adenovirus 14—Associated Respiratory Disease in the United States

Background. First isolated in the Netherlands in 1955 during an outbreak of acute respiratory disease (ARD) among military recruits, human adenovirus 14 (HAdV-14) has historically been considered rare. With no precedent of circulation in North America, HAdV-14 has been isolated from military and civilian cases of ARD of variable severity since 2003 in the United States. Methods. Ninety-nine isolates from military and civilian cases from different geographic locations and circulation periods were characterized by restriction enzyme analysis of viral DNA and select gene sequencing. Results. All examined viruses were found to be identical and to belong to a new genome type designated "HAdV-14pl" (formerly known as "14a"). Comparative alignments of EIA, hexon, and fiber gene sequences with other subspecies B2 HAdVs suggest that HAdV-14p1, like the closely related HAdV-11a, arose from recombination among similar HAdV-11 and HAdV-14 ancestral strains. A deletion of 2 amino acids in the knob region of the fiber protein is the only identified unique characteristic of HAdV-14pl. Conclusion. The current geographic distribution of HAdV-14pl involves at least 15 states in the Unites States. The role of the fiber mutations in the recent emergence of HAdV-14pl ARD in North America warrants further study.