. Author manuscript; available in PMC: 2020 Mar 1.

Published in final edited form as: Lancet Infect Dis. 2018 Dec 13;19(3):e89–e95. doi: 10.1016/S1473-3099(18)30443-2

Table 1:

Mechanisms producing spatially aggregated areas of high tuberculosis incidence

Mechanism	Supporting evidence	Real-world example
Local transmission	• Spatially aggregated risk of TST/IGRA conversion • Spatial aggregation of genotypic cluster	Lima, Peru ²³ Concentration of genetically related Mtb isolates in a high-incidence area suggests local transmission as a cause of the hotspot
Concentration of risk factor for progression to active disease	• Co-localization of determinant of tuberculosis disease and tuberculosis incidence hotspot	Urumqi, China ²⁴ Overlapping high incidence areas of tuberculosis and tuberculosis / HIV coinfection
Migration of individuals from areas with higher risks of infection and disease	• Higher tuberculosis incidence in areas where migrants cluster	Shandong province, China ²⁵ Areas of high incidence along major transportation routes

TST = Tuberculin skin test

IGRA = Interferon gamma release assay

Mtb = Mycobacterium tuberculosis