Advancing, promoting and sharing knowledge of health through excellence in teaching, clinical practice and research into the prevention and treatment of illness

Upper-room ultraviolet light and negative air ionization to prevent tuberculosis transmission.

Escombe, AR; Moore, DAJ; Gilman, RH; Navincopa, M; Ticona, E; Mitchell, B; Noakes, C; Martínez, C; Sheen, P; Ramirez, R; et al. Escombe, AR; Moore, DAJ; Gilman, RH; Navincopa, M; Ticona, E; Mitchell, B; Noakes, C; Martínez, C; Sheen, P; Ramirez, R; Quino, W; Gonzalez, A; Friedland, JS; Evans, CA (2009) Upper-room ultraviolet light and negative air ionization to prevent tuberculosis transmission. PLoS Med, 6 (3). e43. ISSN 1549-1676
SGUL Authors: Friedland, Jonathan Samuel

PDF Published Version
Available under License Creative Commons Public Domain Dedication.

Download (562kB) | Preview


BACKGROUND: Institutional tuberculosis (TB) transmission is an important public health problem highlighted by the HIV/AIDS pandemic and the emergence of multidrug- and extensively drug-resistant TB. Effective TB infection control measures are urgently needed. We evaluated the efficacy of upper-room ultraviolet (UV) lights and negative air ionization for preventing airborne TB transmission using a guinea pig air-sampling model to measure the TB infectiousness of ward air. METHODS AND FINDINGS: For 535 consecutive days, exhaust air from an HIV-TB ward in Lima, Perú, was passed through three guinea pig air-sampling enclosures each housing approximately 150 guinea pigs, using a 2-d cycle. On UV-off days, ward air passed in parallel through a control animal enclosure and a similar enclosure containing negative ionizers. On UV-on days, UV lights and mixing fans were turned on in the ward, and a third animal enclosure alone received ward air. TB infection in guinea pigs was defined by monthly tuberculin skin tests. All guinea pigs underwent autopsy to test for TB disease, defined by characteristic autopsy changes or by the culture of Mycobacterium tuberculosis from organs. 35% (106/304) of guinea pigs in the control group developed TB infection, and this was reduced to 14% (43/303) by ionizers, and to 9.5% (29/307) by UV lights (both p < 0.0001 compared with the control group). TB disease was confirmed in 8.6% (26/304) of control group animals, and this was reduced to 4.3% (13/303) by ionizers, and to 3.6% (11/307) by UV lights (both p < 0.03 compared with the control group). Time-to-event analysis demonstrated that TB infection was prevented by ionizers (log-rank 27; p < 0.0001) and by UV lights (log-rank 46; p < 0.0001). Time-to-event analysis also demonstrated that TB disease was prevented by ionizers (log-rank 3.7; p = 0.055) and by UV lights (log-rank 5.4; p = 0.02). An alternative analysis using an airborne infection model demonstrated that ionizers prevented 60% of TB infection and 51% of TB disease, and that UV lights prevented 70% of TB infection and 54% of TB disease. In all analysis strategies, UV lights tended to be more protective than ionizers. CONCLUSIONS: Upper-room UV lights and negative air ionization each prevented most airborne TB transmission detectable by guinea pig air sampling. Provided there is adequate mixing of room air, upper-room UV light is an effective, low-cost intervention for use in TB infection control in high-risk clinical settings.

Item Type: Article
Additional Information: This is an open-access article distributed under the terms of the Creative Commons Public Domain declaration, which stipulates that, once placed in the public domain, this work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose.
Keywords: Air Ionization, Air Microbiology, Air Pollution, Indoor, Animals, Anions, Cross Infection, Guinea Pigs, HIV Infections, Housing, Animal, Humans, Mycobacterium tuberculosis, Patient Isolators, Patients' Rooms, Tuberculosis, Ultraviolet Rays, Ventilation, Animals, Humans, Guinea Pigs, Mycobacterium tuberculosis, Tuberculosis, Cross Infection, HIV Infections, Anions, Patient Isolators, Air Microbiology, Housing, Animal, Ventilation, Air Ionization, Ultraviolet Rays, Air Pollution, Indoor, Patients' Rooms, Science & Technology, Life Sciences & Biomedicine, Medicine, General & Internal, General & Internal Medicine, ELECTROSTATIC SPACE-CHARGE, REDUCING AIRBORNE PATHOGENS, GERMICIDAL IRRADIATION, NOSOCOMIAL TUBERCULOSIS, SALMONELLA-ENTERITIDIS, RESISTANT TUBERCULOSIS, HATCHING CABINETS, INFECTED PATIENTS, DISINFECTION, RISK, 11 Medical And Health Sciences, General & Internal Medicine
Journal or Publication Title: PLoS Med
ISSN: 1549-1676
Language: eng
17 March 2009Published
21 January 2009Accepted
Publisher License: Creative Commons: Public Domain Dedication
Project IDFunderFunder ID
UNSPECIFIEDEngineering and Physical Sciences Research Council
UNSPECIFIEDSir Halley Stewart Trust
UNSPECIFIEDUnited States Agency for International Development
UNSPECIFIEDInnovation for Health and DevelopmentUNSPECIFIED
PubMed ID: 19296717
Web of Science ID: WOS:000266214700007
Go to PubMed abstract
Publisher's version:

Actions (login required)

Edit Item Edit Item