Date Published: January 23, 2017
Publisher: Public Library of Science
Author(s): Ji Young Park, Bong-Joon Kim, Eun Jung Lee, Kwi Sung Park, Hee Sun Park, Sung Soo Jung, Ju Ock Kim, Linda A Selvey.
The number of pneumonia patients increased suddenly in Korean military hospitals in late December 2014, indicating the urgent need for an epidemic outbreak investigation.
We conducted a prospective study of pneumonia etiology among immunocompetent young adults admitted to Daejeon Armed Forces hospital. Patient blood and sputum samples were subjected to conventional culture, serology, and polymerase chain reaction tests for respiratory viruses and atypical pathogens.
From January to May 2015, we enrolled 191 (189 male) adults with pneumonia; the mean age was 20.1 ± 1.3 years. Five patients had severe pneumonia, and one died. Pathogenic human adenoviruses were most common (HAdV, 153/191 [80.1%]), indicating a HAdV pneumonia outbreak. Genotyping of 35 isolates indicated that 34 matched HAdV-55 and one matched HAdV-2. HAdV pneumonia infected recruit trainees most frequently. High and prolonged fever, nasal congestion, sore throat, and pharyngeal inflammation were significantly more common in the HAdV pneumonia group, compared to patients with other or unknown causes of pneumonia. Only 12% of HAdV pneumonia patients displayed leukocytosis, whereas febrile leukopenia (62.7%) and thrombocytopenia (41%) were commonly observed. HAdV pneumonia patient chest CT scans displayed ground glass opacity (with or without septal thickness) with consolidation in 50.0% of patients.
An outbreak of HAdV respiratory infection occurred at the Korean military training center. HAdV pneumonia exhibited specific laboratory and clinical features, and although most patients were cured without complication, some progressed to respiratory failure and fatality. Therefore, HAdV vaccine should be provided to military trainees in Korea.
Viral respiratory infection is particularly important in military populations who experience overexertion, psychological stress, and crowding within confined spaces . There are many reports of respiratory virus outbreaks in the military [1–3]. In many settings, human adenovirus (HAdV) was the main causative pathogen and occasionally led to death [3, 4]. HAdVs are also important in the pathogenesis of community acquired pneumonia (CAP) among both immunocompetent and immunocompromised individuals [5, 6]. Although despite reports of a low prevalence in previous studies (1.4–4%), adenovirus-related CAP was recently ranked in the top 10 etiologies of CAP by larger studies [7, 8]. Moreover, HAdV is easily transmittable and can be highly contagious . The clinical features of respiratory adenoviral infection among military personnel were described previously; however, HAdV pneumonia in immunocompetent individuals and risk factors of disease progression to severe pneumonia or acute respiratory failure have not been well studied.
Our results show that an outbreak of HAdV pneumonia occurred in Korean military training centers and indicate that emergent-type HAdV-55 infections might have caused the outbreak. In this outbreak, HAdV pneumonia was associated with specific clinical symptoms, laboratory results, and chest CT scan findings.