Quantification of tuberculosis exposure in a high-burdened setting

Area of Science:

• Microbiology
• Epidemiology
• Public Health

Background:

• Aerosolized Mycobacterium tuberculosis (Mtb) has been detected across various tuberculosis states in high-burden settings.
• Understanding Mtb exposure rates is crucial for effective tuberculosis control.

Purpose of the Study:

• To estimate the rate of Mtb exposure in tuberculosis-endemic communities.
• To model the dynamics of Mtb bioaerosol prevalence and clearance.

Main Methods:

• Utilized sensitive aerosol sampling and detection methodologies.
• Employed a Bayesian inference approach with a reversible catalytic model.
• Fitted the model to age-specific, respiratory bioaerosol Mtb prevalence data.
• Incorporated longitudinal monitoring data for Mtb bioaerosol clearance rates.

Main Results:

• Estimated an Mtb exposure rate of 5.1 per year, based on a 62.6% bioaerosol Mtb prevalence and an 83-day clearance half-life.
• Found the exposure rate estimate to be sensitive to bioaerosol Mtb population prevalence.
• Determined that a reversible catalytic model provided a better fit to the data than a non-reversible model.

Conclusions:

• Findings imply an extremely high rate of Mtb exposure in tuberculosis-endemic communities.
• Suggests rapid cycling between Mtb bioaerosol carriage and clearance.
• Estimated exposure rates are an order of magnitude greater than previously published annual Mtb infection rates.