Spread of Mycobacterium tuberculosis in a community implementing recommended elements of tuberculosis control.
BACKGROUND
Despite improvements in tuberculosis (TB) control during the past decade, Mycobacterium tuberculosis transmission and resulting disease continue to occur in the United States.


OBJECTIVE
To determine the primary reasons for disease development from a particular strain of M tuberculosis.


METHODS
Population-based, molecular epidemiological study.


METHODS
Urban community in the San Francisco Bay area of California with recommended elements of TB control in place.


METHODS
Seventy-three TB cases were reported in 1996-1997 that resulted from 1 strain of M tuberculosis as identified by TB genotyping and epidemiological linkage.


METHODS
Transmission patterns involving source and secondary case-patients; primary reasons for disease development.


RESULTS
Seventy-three (33%) of 221 TB case-patients in this community resulted from this strain of M tuberculosis. Thirty-nine (53%) of the 73 case-patients developed TB because they were not identified as contacts of source case-patients; 20 case-patients (27%) developed TB because of delayed diagnosis of their sources; and 13 case-patients (18%) developed TB because of problems associated with the evaluation or treatment of contacts; and 1 case-patient (1%) developed TB because of delay in being elicited as a contact. Of the 51 TB cases identified with sources, 49 (96%) were infected within the 2 years prior to diagnosis.


CONCLUSIONS
Our results indicate that in a community that has implemented the essential elements of TB control, TB from ongoing transmission of M tuberculosis will continue to develop unless patients are diagnosed earlier and contacts are more completely identified. JAMA. 2000.
Chin
D P
DP
Tuberculosis Control Branch and Microbial Disease Laboratory, California Department of Health Services, Berkeley, USA. chind@chn.wpro.who.int
Crane
C M
CM
Diul
M Y
MY
Sun
S J
SJ
Agraz
R
R
Taylor
S
S
Desmond
E
E
Wise
F
F
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D016000:Cluster Analysis; D016358:Contact Tracing; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D009169:Mycobacterium tuberculosis / Q000235:genetics*; D012495:San Francisco / Q000453:epidemiology; D014376:Tuberculosis / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control* / Q000635:transmission