Hiroyuki Furuya1, Michiko Nagamine, Tetsu Watanabe. 1. Basic Clinical Science and Public Health, Tokai University School of Medicine, Isehara, Kanagawa, 259-1193, Japan, furuya@is.icc.u-tokai.ac.jp
Abstract
OBJECTIVE: People who live under fragile living conditions may stay overnight in Internet cafés in urban areas. An outbreak of tuberculosis (TB), the routes of which were possibly related to such a facility, has been reported. The purpose of this study was to use a mathematical model to quantify the public health risk of TB infection in such a facility. METHODS: The reproduction number for airborne infection in an enclosed space (R (A)) was estimated using a Wells-Riley model. First, we estimated R (A) for the TB infection based on the report of the TB outbreak in the Internet café. Second, TB infectious dose, number of days of exposure, and air-exchange rate in the facility were varied to estimate the effect of TB risk settings and environmental factors. RESULTS: We assumed that TB patients and 59 susceptible subjects stayed for 150 days in a room where the air-exchange rate was five per hour. Using the estimated median R (A) of 44.14, the TB infection rate was 74.6%. This result was similar to the epidemiological report that the TB infection rate among employees in the Internet café was 70%. The median R (A) increased linearly as the number of days of exposure increased. The slope of the change in median R (A) divided by the change in the number of days of exposure increased exponentially as air-exchange rate decreased; thus air ventilation in a facility may be essential to prevent TB infection. CONCLUSIONS: Appropriate air ventilation in facilities such as Internet cafés is needed as part of a TB-control program in metropolitan areas.
OBJECTIVE:People who live under fragile living conditions may stay overnight in Internet cafés in urban areas. An outbreak of tuberculosis (TB), the routes of which were possibly related to such a facility, has been reported. The purpose of this study was to use a mathematical model to quantify the public health risk of TB infection in such a facility. METHODS: The reproduction number for airborne infection in an enclosed space (R (A)) was estimated using a Wells-Riley model. First, we estimated R (A) for the TB infection based on the report of the TB outbreak in the Internet café. Second, TB infectious dose, number of days of exposure, and air-exchange rate in the facility were varied to estimate the effect of TB risk settings and environmental factors. RESULTS: We assumed that TB patients and 59 susceptible subjects stayed for 150 days in a room where the air-exchange rate was five per hour. Using the estimated median R (A) of 44.14, the TB infection rate was 74.6%. This result was similar to the epidemiological report that the TB infection rate among employees in the Internet café was 70%. The median R (A) increased linearly as the number of days of exposure increased. The slope of the change in median R (A) divided by the change in the number of days of exposure increased exponentially as air-exchange rate decreased; thus air ventilation in a facility may be essential to prevent TB infection. CONCLUSIONS: Appropriate air ventilation in facilities such as Internet cafés is needed as part of a TB-control program in metropolitan areas.
Authors: Robin Wood; Simon Johnstone-Robertson; Pieter Uys; John Hargrove; Keren Middelkoop; Stephen D Lawn; Linda-Gail Bekker Journal: Clin Infect Dis Date: 2010-08-15 Impact factor: 9.079
Authors: Robin Wood; Carl Morrow; Samuel Ginsberg; Elizabeth Piccoli; Darryl Kalil; Angelina Sassi; Rochelle P Walensky; Jason R Andrews Journal: PLoS One Date: 2014-09-02 Impact factor: 3.240
Authors: Eugene T Richardson; Carl D Morrow; Darryl B Kalil; Samuel Ginsberg; Linda-Gail Bekker; Robin Wood Journal: PLoS One Date: 2014-05-07 Impact factor: 3.240