Mycobacterium tuberculosis transmission dynamics within prisons: a population-based genomic study.

Area of Science:

• Public Health
• Infectious Disease Epidemiology
• Genomic Surveillance

Background:

• Understanding Mycobacterium tuberculosis transmission dynamics is crucial for controlling the global pandemic.
• Identifying transmission sources in high-incidence settings like prisons is an urgent public health priority.
• This study investigated contact types associated with tuberculosis transmission risk within correctional facilities.

Purpose of the Study:

• To determine the specific types of close contacts that contribute to Mycobacterium tuberculosis transmission within prisons.
• To quantify the association between different prison exposure scenarios and tuberculosis transmission risk.

Main Methods:

• Genomic surveillance of Mycobacterium tuberculosis isolates from a Brazilian prison system.
• Whole genome sequencing of isolates and collection of detailed incarceration histories.
• Statistical modeling of transmission linkages based on genomic clustering and prison exposure data.

Main Results:

• A month of close cell exposure increased tuberculosis transmission odds by 14%; six months doubled the odds.
• Most individuals with tuberculosis had frequent close cell exposures to other infectious individuals.
• Prisoner transfers created a highly interconnected network, facilitating disease spread.

Conclusions:

• Cell-level exposures significantly contribute to Mycobacterium tuberculosis transmission, but most transmission occurs outside cells.
• Expansion of prison-wide screenings, tuberculosis preventive therapy, and structural interventions is urgently needed.
• Findings highlight the need for comprehensive strategies to reduce tuberculosis transmission in congregate settings.