Combining environmental assessment and contact investigations to make tuberculosis screening decisions.
METHODS
A combination of environmental measurement and mathematical modelling may provide a more quantitative method to inform the tuberculosis (TB) screening process in non-household settings following diagnosis of an infectious case.


OBJECTIVE
To explore different methods for  environmental assessment and mathematical modelling to predict TB transmission risk and devise a tool for public health practitioners for use in TB investigations.


METHODS
Parameters including air flow, carbon dioxide (CO(2)) and airborne particles were measured over 3 working  days in an office with a staff member with infectious TB. The Wells-Riley model was applied to predict transmission rates.


RESULTS
The results suggested that poor ventilation and well-mixed air led to equal exposure of staff members to airborne TB bacilli. The model's prediction of attack  rate (42%) supported the actual number of infections that occurred (50%).


CONCLUSIONS
This study supports the use of environmental assessment and modelling as a tool for public health practitioners to determine the extent of TB exposure and to inform TB screening strategies. CO(2)  and airborne particle profiles, both measured via a handheld device, provide the greatest practicality and amount of information that public health practitioners can use. Further studies will validate the level of screening required related to these measurements.
Healthy Infrastructure Research Centre, Civil, Environmental and Geomatic Engineering, University College London, London, UK.
L J
LJ
Pankhurst
S
S
Anaraki
K M
KM
Lai
D000391:Air Microbiology; D016902:Air Pollution, Indoor; D002245:Carbon Dioxide / Q000032:analysis; D016358:Contact Tracing; D003661:Decision Support Techniques; D004777:Environment; D004784:Environmental Monitoring / Q000379:methods; D062665:Epidemiological Monitoring; D006801:Humans; D008131:London; D008403:Mass Screening; D008962:Models, Theoretical; D016273:Occupational Exposure; D016272:Occupational Health; D052638:Particulate Matter / Q000032:analysis; D018579:Patient Selection; D011237:Predictive Value of Tests; D018570:Risk Assessment; D012307:Risk Factors; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology / Q000635:transmission; D014691:Ventilation; D017132:Workplace
D052638:Particulate Matter; D002245:Carbon Dioxide