Human Adenovirus 14a: Update on activity and status of our knowledge about this emerging respiratory pathogen in the United States
Session I or III: Kajon
Title of Contribution: Human Adenovirus 14a: Update on activity and status of our knowledge about this emerging respiratory pathogen in the United States
Author(s): Adriana E. Kajon1, Xiaoyan Lu 2, David Metzgar3, and Dean D. Erdman2
Affiliation(s):
1-Infectious Disease Program, Lovelace Respiratory Research Institute, Albuquerque,NM, USA.
2-Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA;
3-DoD Center for Deployment Health Research, Naval Health Research Center, San Diego, CA,USA.
Abstract:
Among the species B2 adenovirus (Ad) serotypes with a record of association with acute respiratory disease (ARD), Ad14 is by far the rarest. First discovered during an outbreak of acute respiratory disease among military recruits in 1955 in The Netherlands, and initially referred to as “agent De Wit”, Ad14 has historically displayed a very restricted circulation in association with outbreaks of respiratory illness in Europe and Asia in the mid 1950s to early 1960s. With no precedent of previous circulation in the United States, Ad14 has been continuously detected during outbreaks of respiratory illness among military recruits throughout the United States since March 2006, and also associated with civilian cases and outbreaks of severe pneumonia and deaths among civilians since as early as 2003 and as recently as September 2008, affecting both pediatric and adult patients in several states. Restriction enzyme analysis of viral genomic DNA and sequencing of the E1A coding region, the hexon gene and the fiber gene of Ad14 isolates representing military and civilian cases, different years of circulation and geographic sites showed all examined viruses to be identical, and to belong to a new genome type designated Ad14a. In order to further characterize this emerging virus and gather additional information to elucidate its natural history, we conducted a comparative analysis with other closely related species B2 adenoviruses with a record of circulation in the United States and other countries in association with respiratory disease. Like the prototype (Ad14p), this new DNA variant of Ad14 is closely related to species B2 genome types Ad11a and Ad11-14. The alignment of E1A hexon and fiber sequences and analysis of the relative percentage of co-migrating restriction fragments, suggest that Ad14a is a recombinant virus with an 11-like 5’ end and a 14-like fiber gene.
Despite the high sequence similarity with both Ad14p and the closely related Ad11a and Ad11-14, Ad14a encodes a unique predicted fiber protein with a distinct 6 bp deletion near the recognized receptor binding site in the knob region corresponding to amino acids 251 and 252 of the fiber of Ad14p. The closest related species B2 adenovirus detected in the United States in association with ARD is the Ad11a strain responsible for a 1997 outbreak in South Dakota which in our hands is indistinguishable from currently circulating Asian strains of Ad11a.
