Tuberculosis Infectiousness and Host Susceptibility

• Type of Material: Article
• Authors: Richard D Turner, Kings College Hospital London; Christopher Chiu, Imperial College London; Gavin J Churchyard, Aurum Institute; Hanif Esmail, University of Oxford; David M Lewinsohn, Oregon Health & Science University; Neel Gandhi, Emory University; Kevin P Fennelly, National Heart, Lung, and Blood Institute
• Language: English
• Date: 2017-10-01
• Publisher: Oxford University Press (OUP): Policy B - Oxford Open Option C
• Publication Version: Final Published Version
• Copyright Statement: © 2017 The Author.
• License: Creative Commons Attribution 3.0 IGO License
• Final Published Version (URL): http://dx.doi.org/10.1093/infdis/jix361
• Title of Journal or Parent Work: Journal of Infectious Diseases
• ISSN: 0022-1899
• Volume: 216
• Issue: suppl_6
• Start Page: S636
• End Page: S643
• Grant/Funding Information: This work was supported by the Division of AIDS, National Institute of Allergy and Infectious Disease, National Institute of Health, Department of Health and Human Services (contract HHSN272201100001G [Research Support Services for the Division of AIDS]), the Bill and Melinda Gates Foundation, the Centers for Disease Control and Prevention, and the South African Medical Research Council.
• Keywords: CONTROLLED-TRIAL; MULTIDRUG-RESISTANT TUBERCULOSIS; HEALTH-CARE WORKERS; Life Sciences & Biomedicine; transmission; infectiousness; AIRBORNE TRANSMISSION; Immunology; Infectious Diseases; TUBERCLE-BACILLI; Microbiology; Tuberculosis; HOUSEHOLD CONTACTS; Science & Technology; susceptibility; MYCOBACTERIUM-TUBERCULOSIS; COUGH FREQUENCY; PULMONARY TUBERCULOSIS; ISONIAZID PREVENTIVE THERAPY
• Research Categories: Biology, Microbiology; Health Sciences, Immunology

Abstract

The transmission of tuberculosis is complex. Necessary factors include a source case with respiratory disease that has developed sufficiently for Mycobacterium tuberculosis to be present in the airways. Viable bacilli must then be released as an aerosol via the respiratory tract of the source case. This is presumed to occur predominantly by coughing but may also happen by other means. Airborne bacilli must be capable of surviving in the external environment before inhalation into a new potential host-steps influenced by ambient conditions and crowding and by M. tuberculosis itself. Innate and adaptive host defenses will then influence whether new infection results; a process that is difficult to study owing to a paucity of animal models and an inability to measure infection directly. This review offers an overview of these steps and highlights the many gaps in knowledge that remain.