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A Tuberculosis Molecular Bacterial Load Assay TB-MBLA
Published on: April 30, 2020
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Spatial overlap links seemingly unconnected genotype-matched TB cases in rural Uganda
Gabriel Chamie1, Midori Kato-Maeda2, Devy M Emperador1
1Division of HIV, Infectious Diseases and Global Medicine, University of California, San Francisco, California, United States of America.
Plos One
|February 14, 2018
Summary
Understanding tuberculosis (TB) transmission in high HIV settings is key for prevention. This study found TB transmission often occurs between casual contacts in shared locations, especially healthcare settings, not just close contacts.
Area of Science:
- Molecular epidemiology of infectious diseases
- Public health and preventative medicine
- Tuberculosis (TB) research
Background:
- Incomplete understanding of TB transmission dynamics in high HIV prevalence settings hinders prevention efforts.
- Identifying transmission hotspots is crucial for targeted case finding and interrupting TB spread.
Purpose of the Study:
- To investigate TB transmission dynamics in a high HIV prevalence setting in Uganda.
- To identify potential TB transmission sites by linking molecularly-matched TB cases through social networks and spatial overlap.
- To assess the role of healthcare settings in TB transmission among casual contacts.
Main Methods:
- Recruited adults initiating TB treatment in a Ugandan community from 2012-2015.
- Conducted household contact investigations and collected data on social contacts and frequented locations.
- Used Mycobacterium tuberculosis (MTB) 24-loci MIRU-VNTR and spoligotyping for molecular genotyping.
- Identified epidemiologic links by analyzing social networks and mapping spatial overlap (≤100m) of genotype-matched cases.
Main Results:
- 39% of TB cases belonged to distinct MTB genotype-matched clusters.
- No genotype-clustered cases shared households or named non-household contacts.
- Spatial overlap at specific locations, particularly healthcare settings (5/6 clusters), identified epidemiologic links in 40% of clusters.
- Genotype-clustered TB social networks showed significantly higher density based on shared clinics compared to non-clustered networks.
Conclusions:
- Links between MTB genotype-matched TB cases were primarily identified through shared locations, especially healthcare settings, rather than direct contact tracing.
- Findings suggest a significant proportion of TB transmission occurs between casual contacts in shared public spaces.
- Emphasizes the urgent need for enhanced infection control measures in healthcare facilities in rural African settings to curb TB transmission.
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