Transmission Dynamics of Tuberculosis: an Epidemiological and Biological Perspective

Abstract

Tuberculosis (TB) remains one of the world’s leading infectious diseases, with approximately 10.4 million new cases and 1.8 million deaths reported in 2015, including those co-infected with HIV. Despite ongoing global efforts, TB transmission persists as a major public health challenge. This article explores the epidemiological and biological aspects of TB transmission, presenting a cascade model that outlines six essential steps from source case to disease development. Emphasis is placed on identifying the sources of transmission, understanding transmission settings, and recognizing the populations most susceptible to TB. Historical insights from Robert Koch to contemporary genomic tracking highlight how our knowledge of TB transmission has evolved. The article also discusses the critical role of social determinants such as poverty, overcrowding, malnutrition, and HIV prevalence in facilitating transmission, particularly in high-burden settings. Furthermore, the review identifies interventions, including household contact screening, infection control in healthcare settings, geospatial targeting of high-transmission areas, and preventive therapy. Modeling studies suggest that comprehensive, scaled interventions combined with the development of new diagnostics, drugs, and vaccines could significantly accelerate progress toward TB elimination. Finally, the importance of continued research and innovation in TB transmission dynamics is emphasized, as well as the need for integrated approaches that combine biomedical, behavioral, and structural interventions. The knowledge gained from TB transmission dynamics is also applicable to other airborne diseases, reinforcing the relevance of this research in a broader public health context.