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Am J Trop Med Hyg. 2015 Oct;93(4):739-46. doi: 10.4269/ajtmh.15-0166. Epub 2015 Jul 20.

The Impact of Ventilation and Early Diagnosis on Tuberculosis Transmission in Brazilian Prisons.

Author information

1
Yale School of Public Health, New Haven, Connecticut; Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil; Hospital Universitário de Dourados, Universidade Federal da Grande Dourados, Dourados, Brazil; Stanford University School of Medicine, Stanford, California; Faculdade de Ciências da Saúde, Universidade Federal da Grande Dourados, Dourados, Brazil; Fundação Oswaldo Cruz, Ministério da Saúde, Campo Grande, Brazil.
2
Yale School of Public Health, New Haven, Connecticut; Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil; Hospital Universitário de Dourados, Universidade Federal da Grande Dourados, Dourados, Brazil; Stanford University School of Medicine, Stanford, California; Faculdade de Ciências da Saúde, Universidade Federal da Grande Dourados, Dourados, Brazil; Fundação Oswaldo Cruz, Ministério da Saúde, Campo Grande, Brazil jandr@stanford.edu.

Abstract

Prisoners have among the highest incidence of tuberculosis (TB) globally. However, the contribution of the prison environment on transmission is not well understood and structural characteristics have received little attention as effective epidemiological interventions in TB control. We evaluated architectural characteristics and estimated ventilation rates in 141 cells in three prisons in central west Brazil using steady-state exhaled carbon dioxide (CO2) levels. We used a modified Wells-Riley equation to estimate the probability of infection for inmates sharing a cell with an infectious case and projected the impact of interventions, including early diagnosis and improved ventilation. Overall, prison cells were densely populated (mean 2.1 m(2) per occupant) and poorly ventilated, with only three cells meeting World Health Organization (WHO) standards for per-person ventilation (60 L/s) applied in infection control settings. In the absence of interventions, projected mean risk of infection was 78.0% during a 6-month period. Decreasing time-to-diagnosis by 25% reduced transmission risk by 8.3%. Improving ventilation to WHO standards decreased transmission by 38.2%, whereas optimizing cross-ventilation reduced transmission by 64.4%. Prison environments promote high infection risk over short-time intervals. In this context, enhanced diagnostics have a limited impact on reducing transmission. Improving natural ventilation may be required to effectively control TB in prisons.

PMID:
26195459
PMCID:
PMC4596592
DOI:
10.4269/ajtmh.15-0166
[Indexed for MEDLINE]
Free PMC Article

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