Elevated transmission of upper respiratory illness among new recruits in military barracks in Thailand.
BACKGROUND
New recruits within military barracks present conditions favorable for the spread of respiratory pathogens. However, respiratory pathogen transmission in such confined settings in the tropics has not been well studied.


METHODS
Recruits in four successive Royal Thai Army basic training classes living in military barracks were monitored for the symptoms of influenza-like illness (ILI) or upper respiratory illness (URI). Classes 1 and 2 were also monitored after basic training. Nasal/throat swabs from acute illnesses were collected and tested by influenza RT-PCR (all four classes). In addition, class 1 had multiplex PCR performed along with the analysis of bed locations within the barracks.


RESULTS
Influenza-like illness/upper respiratory illness rates ranged from 4·7 to 6·9 per 100 recruit-weeks in the four classes and generally decreased during the course of basic training (P < 0·05 in three of four classes). Rates during basic training were 1·7 (95% CI: 1·29, 2·29) and 2·5 (95% CI: 1·5, 4·1) times higher than after basic training (classes 1 and 2, respectively). In class 1, coronavirus, parainfluenza virus, and rhinovirus were the most commonly identified respiratory pathogens; only one influenza PCR-positive infection was detected in all four classes. Bed locations of URI/ILI cases in class 1 tended to be in closer proximity to each other.


CONCLUSIONS
Basic training recruits in military barracks in the tropics had high rates of acute respiratory illnesses with illness patterns consistent with external seeding followed by substantial internal transmission. Our findings may contribute to control measures in similar confined settings both within and outside the military.
Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.
Jens W
http://orcid.org/0000-0002-5676-2990
JW
Levy
Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.
Piraya
P
Bhoomiboonchoo
Phramongkutklao Hospital, Bangkok, Thailand.
Sriluck
S
Simasathien
Department of Epidemiology, Johns Hopkins, Bloomberg School of Public Health, Baltimore, MD, USA.
Henrik
H
Salje
Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.
Angkana
http://orcid.org/0000-0002-9857-3506
A
Huang
Phramongkutklao Hospital, Bangkok, Thailand.
Ram
R
Rangsin
Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.
Richard G
RG
Jarman
Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.
Stefan
S
Fernandez
Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.
Chonticha
C
Klungthong
Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.
Kittinun
K
Hussem
Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.
Robert V
RV
Gibbons
Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.
In-Kyu
IK
Yoon
Human; Thailand; military; respiratory tract infections; transmission