Journal of Infectious Diseases
15 May 2009  Volume 199, Number 10
http://www.journals.uchicago.edu/toc/jid/current

EDITORIAL COMMENTARY
Human Adenovirus 14a: A New Epidemic Threat
Gregory C. Gray and Margaret L. Chorazy
Center for Emerging Infectious Diseases, Department of Epidemiology, College of Public Health, University of Iowa, Iowa City

MAJOR ARTICLE
Outbreak of Severe Respiratory Disease Associated with Emergent Human Adenovirus Serotype 14 at a US Air Force Training Facility in 2007
Jacqueline E. Tate,1; Michel L. Bunning,3; Lisa Lott,4; Xiaoyan Lu,1; John Su,2,6; David Metzgar,7; Lorie Brosch,3; Catherine A. Panozzo,1; Vincent C. Marconi,5; Dennis J. Faix,7; Mila Prill,1; Brian Johnson,1; Dean D. Erdman,1; Vincent Fonseca,6; Larry J. Anderson,1 and Marc-Alain Widdowson1

Background.In 2007, a US Air Force training facility reported a cluster of severe respiratory illnesses associated with a rare human adenovirus (Ad) serotype, Ad14. We investigated this outbreak to better understand its epidemiology, clinical spectrum, and associated risk factors.

Methods.Data were collected from ongoing febrile respiratory illness (FRI) surveillance and from a retrospective cohort investigation. Because an Ad7 vaccine is in development, Ad7 antibody titers in pretraining serum samples from trainees with mild and those with severe Ad14 illness were compared.

Results.During 2007, an estimated 551 (48%) of 1147 trainees with FRI were infected with Ad14; 23 were hospitalized with pneumonia, 4 required admission to an intensive care unit, and 1 died. Among cohort members ( ), the Ad14 infection rate was high (50%). Of those infected, 40% experienced FRI. No cohort members were hospitalized. Male sex (risk ratio [RR], 4.7 [95% confidence interval {CI}, 2.2-10.1]) and an ill close contact (RR, 1.6 [95% CI, 1.2-2.2]) were associated with infection. Preexisting Ad7 neutralizing antibodies were found in 7 (37%) of 19 Ad14‐positive trainees with mild illness but in 0 of 16 trainees with Ad14 pneumonia ( ).

Conclusions.Emergence of Ad14, a rare Ad serotype, caused a protracted outbreak of respiratory illness among military recruits. Most infected recruits experienced FRI or milder illnesses. Some required hospitalization, and 1 died. Natural Ad7 infection may protect against severe Ad14 illness.

1Division of Viral Diseases and 2Office of Workforce and Career Development, Centers for Disease Control and Prevention, Atlanta, Georgia; 337th Medical Group, US Air Force, 4Epidemic Outbreak Surveillance, Modernization Directorate, Office of the Air Force Surgeon General, and 5Infectious Disease Service, Wilford Hall US Air Force Medical Center, Lackland Air Force Base, San Antonio, and 6Texas Department of State Health Services, Austin; 7Naval Health Research Center, San Diego, California

MAJOR ARTICLE
A Community‐Based Outbreak of Severe Respiratory Illness Caused by Human Adenovirus Serotype 14
Paul F. Lewis,1,a,b; Mark A. Schmidt,1,a; Xiaoyan Lu,3; Dean D. Erdman,3; Mary Campbell,2 ; Ann Thomas,1; Paul R. Cieslak,1; La Donna Grenz,1; Laura Tsaknardis,1; Curt Gleaves,2; Brian Kendall,2,b and David Gilbert2

Background.Human adenoviruses (Ads) typically cause mild illnesses in otherwise healthy hosts. We investigated a community‐based outbreak that had substantial morbidity caused primarily by Ad14, an uncommon serotype.

Methods.We retrospectively reviewed the medical records of all patients with confirmed cases of Ad infection from 1 November 2006 through 31 July 2007 in Oregon. Isolates were typed by sequencing. We analyzed clinical and laboratory variables to identify risk factors for severe Ad14 disease.

Results.Ad14 first emerged in Oregon in 2005. Of 67 cases of Ad infection detected during the study period, 40 (60%) involved Ad14. Most of the 38 Ad14‐infected patients who had medical records available for review presented with fever and cough; 29 (76%) required hospitalization, 23 (61%) required supplemental oxygen, 18 (47%) required critical care, 9 (24%) required vasopressors, and 7 (18%) died. Lobar infiltrates on chest radiographs suggestive of bacterial pneumonia were common among those needing hospitalization. Older age, chronic underlying condition, low absolute lymphocyte counts, and elevated creatinine levels were associated with severe illness. Except for 1 case of possible hospital transmission, we identified no epidemiological links among patients.

Conclusion.Ad14 emerged in Oregon in 2005 and became the predominant circulating type by 2007. Infection with this uncommon virus was primarily associated with a community‐acquired pneumonia syndrome and caused substantial morbidity and mortality.

1Oregon Public Health Division and 2Providence Portland Medical Center, Portland; 3Centers for Disease Control and Prevention, Atlanta, Georgia