Severe Respiratory Disease Associated with Adenovirus Serotype 14
Abstract and Commentary
By Dean L. Winslow, MD, FACP, FIDSA, Chief, Division of AIDS Medicine, Santa Clara Valley Medical Center; Clinical Professor, Stanford University School of Medicine. Dr. Winslow serves as a consultant for Siemens Diagnostics, and is on the speaker's bureau for Boehringer-Ingelheim and GSK. This article originally appeared in the July 2009 issue of Infectious Disease Alert. It was edited by Stan Deresinski, MD, FACP, and peer reviewed by Connie Price, MD. Dr. Deresinski is Clinical Professor of Medicine, Stanford University; Associate Chief of Infectious Diseases, Santa Clara Valley Medical Center, and Dr. Price is Assistant Professor, University of Colorado School of Medicine. Dr. Deresinski serves on the speaker's bureau for Merck, Pharmacia, GlaxoSmithKline, Pfizer, Bayer, and Wyeth, and does research for Merck, and Dr. Price reports no financial relationships relevant to this field of study.
Synopsis: Adenovirus 14 (Ad14) has emerged as a cause of febrile respiratory illness (FRI) and has resulted in pneumonia in a significant number of patients. In an outbreak at Lackland AFB in 2007, 48% of 1,147 trainees with FRI were infected with Ad14; 16 patients developed pneumonia and one patient died. Ad14 was also observed to have emerged in Oregon in 2005, and became the predominant circulating serotype by 2007. In this outbreak, a high proportion of patients were hospitalized, required ICU admission and vasopressors, and seven patients died.
Sources: Tate JE, et al. Outbreak of severe respiratory disease associated with emergent human adenovirus serotype 14 at a US Air Force training facility in 2007. J Infect Dis. 2009;199:1419-1426; Lewis, PF, et al. A community-based outbreak of severe respiratory illness caused by human adenovirus serotype 14. J Infect Dis. 2009;199:1427-1434.
A cluster of febrile respiratory illness (FRI) associated with Ad14 was reported at Lackland AFB, TX, in 2007. Combined surveillance and retrospective cohort investigation identified 1,147 basic military trainees with FRI; 551 (48%) were infected with Ad14. Of those, 23 were hospitalized with pneumonia, four required ICU admission, and one died. In a cohort of four training flights (n = 173), the infection rate was 50%. Male sex and close contact with an ill individual were identified as risk factors for infection with Ad14. Pre-existing antibodies to Ad7 were found in 7/19 (37%) Ad14-positive trainees with mild illness and in 0/16 trainees with Ad14 pneumonia. A community-based outbreak of Ad14 also was identified in Oregon. Retrospective reviews of the medical records of all the cases of confirmed Ad14 were performed. Of the 38 cases of confirmed Ad14 infection, with records available for review, most patients presented with fever and cough, 76% required hospitalization, 61% required supplemental oxygen, 24% required vasopressors, and 18% died. Lobar infiltrates were common among those patients requiring hospitalization. Older age, chronic underlying conditions, low absolute lymphocyte count, and elevated serum creatinine were associated with severe illness.
Commentary
There are 52 human Ad serotypes which produce many different clinical illnesses, including pharyngoconjunctival fever, keratoconjunctivitis, pneumonia, hemorrhagic cystitis, gastroenteritis, acute respiratory disease, disseminated infection, cardiomyopathy, and meningoencephalitis. Until recently, Ad14 was rarely reported in the United States, although a few reported outbreaks were seen in Europe and Asia as long ago as the 1950s. Sequencing data from these more recent outbreaks, characterized by more severe clinical disease, show some differences from the original Ad14 strains. Together, these two studies highlight the emergence of Ad14 as an important pathogen capable of causing severe community-acquired pneumonia. While quite a few healthy, young US Air Force recruits developed severe disease, it is important to note that the majority of Airmen infected with Ad14 in the Lackland AFB outbreak reported afebrile or mild disease. Clearly, the retrospective nature of the Oregon study highlights the more serious cases that were captured, since reporting of adenovirus infections relies on passive surveillance and it is likely that only the most seriously ill individuals would be tested for this pathogen. Effective antivirals for treatment of human adenovirus disease are not available. Because of the evidence suggesting that previous natural infection with Ad7 may be protective against severe disease due to Ad14, reintroduction of the previously available Ad4 and Ad7 vaccines might be appropriately targeted to individuals at risk for severe Ad14 disease.
Adenovirus 14 (Ad14) has emerged as a cause of febrile respiratory illness (FRI) and has resulted in pneumonia in a significant number of patients.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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