The role of core groups in transmitting Mycobacterium tuberculosis in a high prevalence community in Southern Mexico.
METHODS
A community in Southern Mexico with a high prevalence of tuberculosis.


OBJECTIVE
To characterize the transmission dynamics in a region with a DOTS-based tuberculosis control program.


METHODS
Community-based screening of chronic coughers between 1 March 1995 and 31 August 1996. Individuals with acid-fast bacilli (AFB) in their sputum were enrolled, interviewed, and had mycobacterial cultures and fingerprinting performed. In-depth interviews were conducted on all persons with DNA fingerprinting.


RESULTS
AFB smears were performed on 1424 individuals, 124 of whom were microbiologically confirmed. Of the 95 cases for whom bacterial DNA fingerprints were available, 38 were in clusters. The largest cluster involved seven individuals who were members of a social network centered on a series of unlicensed bars.


CONCLUSIONS
This population-based molecular epidemiologic study showed that a focus of transmission within a social network accounted for one fourth of transmission which rapidly progressed to disease. These observations raise questions about the potential benefit of targeted tuberculosis control interventions in health jurisdictions approaching WHO-defined DOTS benchmarks.
García-García
M
M
Instituto Nacional de Salud Pública, Cuernavaca, Mexico. garcigar@insp3.insp.mx
Palacios-Martínez
M
M
Ponce-de-León
A
A
Jiménez-Corona
M E
ME
Jiménez-Corona
A
A
Balandrano-Campos
S
S
Olivera-Díaz
H
H
Valdespino-Gómez
J L
JL
Small
P M
PM
D016000:Cluster Analysis; D016172:DNA Fingerprinting; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening; D008800:Mexico / Q000453:epidemiology; D017720:Molecular Epidemiology; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification; D015995:Prevalence; D013183:Sputum / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology* / Q000235:genetics / Q000635:transmission*