Use of a mathematical model to estimate tuberculosis transmission risk in an Internet café

Furuya, Hiroyuki; Nagamine, Michiko; Watanabe, Tetsu

doi:10.1007/s12199-008-0062-9

Cited by 17 publications

(11 citation statements)

References 8 publications

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“…The model in this study was based on the Wells-Riley equation which has been used to examine airborne TB disease transmission since the 1970s 14 in a wide variety of medical and non-medical settings and thus has been useful in examining the relative importance of transmission factors in real-life situations 15-19 . This study used a novel approach of incorporating population data from a specific South African township to populate the Well-Riley equation in order to explore household and non-household TB transmission to pre-school children.…”

Section: Discussionmentioning

confidence: 99%

“…The Wells-Riley equation is a well known transmission model that has been used to describe airborne transmission probabilities of a single enclosed room or space with defined ventilation 14 . The Wells-Riley equation which has been applied to a wide range of transmission scenarios 15-19 was used in combination with the distribution of adults per household and their probability of being infectious in order to explore adult to child TB transmission probabilities.…”

Section: Methodsmentioning

confidence: 99%

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Tuberculosis Transmission to Young Children in a South African Community: Modeling Household and Community Infection Risks

et al. 2010

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Introduction Tuberculosis (TB) transmission is determined by contact between infectious and susceptible individuals. A recent study reported a 4% annual risk of child TB infection (ARTI) in a Southern African township. A model was used to explore the interactions between prevalence of adult TB infection, adult-to-child contacts and household ventilation which could result in such a high ARTI. Methods Number of residents per household and TB incidence were derived from a household census and community TB registers. Using the “Wells-Riley” equation and probability analyses of contact between TB infectious adults and pre-school children, we estimated the ARTI within and outside of the home. Results There was a mean of 2.2 adults per child-household with a 1.35% annual adult smear-positive TB notification rate. The maximal household ARTI was 3% which was primarily determined by the number of resident adults. Transmission risk outside the home increased with numbers of households visited. Transmission probabilities were sensitive to exposure time, ventilation and period of adult infectivity. The benefits of increased ventilation were greatest when the period of infectivity was reduced. Similar reductions in household transmission could be achieved by increasing ventilation from 2 to 6 air changes/hour or separating child and adult sleeping areas. Conclusions The ARTI of pre-school children predominantly results from infectious residents in the home. However, even with limited social interactions, a substantial proportion of transmission may occur from non-resident adults. The benefits of increased ventilation are maximized when the period of infectivity is reduced by prompt treatment of source cases.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Tuberculosis Transmission to Young Children in a South African Community: Modeling Household and Community Infection Risks

et al. 2010

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“…While smear-positive cases were probably all highly infectious, primary smear-positive cases were likely even more so as their contact with susceptible individuals could be closer and more frequent before the outbreak was detected. The existence of super spreaders characterized by wider personal social networks has been observed in other local TB outbreaks (Furuya et al, 2009; Gardy et al, 2011), and can make the traditional reproductive number, which is defined in the sense of population average, a less useful measure of transmissibility (Lloyd-Smith et al, 2005). How to target super spreaders for prevention and control, as well as the effectiveness of such strategies, needs to be investigated with mathematical models and field studies for which our estimate of the effective R, specific to a smear-positive primary case, can be potentially useful.…”

Section: Discussionmentioning

confidence: 99%

Transmissibility of tuberculosis among school contacts: An outbreak investigation in a boarding middle school, China

Yang

Wang

et al. 2015

Infection, Genetics and Evolution

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Tuberculosis (TB) outbreak occurred in a boarding middle school of China. We explored its probable sources and quantified the transmissibility and pathogenicity of TB. Clinical evaluation, tuberculin skin testing and chest radiography were conducted to identify TB cases. Mycobacterium tuberculosis isolates underwent genotyping analysis to identify the outbreak source. A chain-binomial transmission model was used to evaluate transmissibility and pathogenicity of TB. A total of 46 active cases were ascertained among 258 students and 15 teachers/staff, an attack rate of 16.8%. Genetic analyses revealed two groups of M. tuberculosis cocirculating during the outbreak and possible importation from local communities. Secondary attack rates among students were 4.1% (2.9%, 5.3%) within grade and 7.9% (4.9%, 11%) within class. An active TB case was estimated to infect 8.4 (7.2, 9.6) susceptible people on average. The smear-positive cases were 28 (8, 101) times as infective as smear-negative cases. Previous BCG vaccination could reduce the probability of developing symptoms after infection by 70% (1.4%, 91%). The integration of clinical evaluation, genetic sequencing, and statistical modeling greatly enhanced our understanding of TB transmission dynamics. Timely diagnosis of smear-positive cases, especially in the early phase of the outbreak, is the key to preventing further spread among close contacts.

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“…In dealing with indoor TB transmission, one usually employs the well‐known deterministic Wells‐Riley mathematical model to account for the probability of infection risk from M. tuberculosis bacilli. ( 1, 4‐6, 19‐22 )…”

Section: Methodsmentioning

confidence: 99%

A Probabilistic Transmission Model to Assess Infection Risk fromMycobacterium Tuberculosisin Commercial Passenger Trains

Chen

Liao

et al. 2010

Risk Analysis

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The objective of this article is to characterize the risk of infection from airborne Mycobacterium tuberculosis bacilli exposure in commercial passenger trains based on a risk-based probabilistic transmission modeling. We investigated the tuberculosis (TB) infection risks among commercial passengers by inhaled aerosol M. tuberculosis bacilli and quantify the patterns of TB transmission in Taiwan High Speed Rail (THSR). A deterministic Wells-Riley mathematical model was used to account for the probability of infection risk from M. tuberculosis bacilli by linking the cough-generated aerosol M. tuberculosis bacilli concentration and particle size distribution. We found that (i) the quantum generation rate of TB was estimated with a lognormal distribution of geometric mean (GM) of 54.29 and geometric standard deviation (GSD) of 3.05 quantum/h at particle size ≤ 5 μm and (ii) the basic reproduction numbers (R 0 ) were estimated to be 0.69 (0.06-6.79), 2.82 (0.32-20.97), and 2.31 (0.25-17.69) for business, standard, and nonreserved cabins, respectively. The results indicate that commercial passengers taking standard and nonreserved cabins had higher transmission risk than those in business cabins based on conservatism. Our results also reveal that even a brief exposure, as in the bronchoscopy cases, can also result in a transmission when the quantum generation rate is high. This study could contribute to a better understanding of the dynamics of TB transmission in commercial passenger trains by assessing the relationship between TB infectiousness, passenger mobility, and key model parameters such as seat occupancy, ventilation rate, and exposure duration.

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Use of a mathematical model to estimate tuberculosis transmission risk in an Internet café

Cited by 17 publications

References 8 publications

Tuberculosis Transmission to Young Children in a South African Community: Modeling Household and Community Infection Risks

Tuberculosis Transmission to Young Children in a South African Community: Modeling Household and Community Infection Risks

Transmissibility of tuberculosis among school contacts: An outbreak investigation in a boarding middle school, China

A Probabilistic Transmission Model to Assess Infection Risk fromMycobacterium Tuberculosisin Commercial Passenger Trains

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