Spread of Mycobacterium tuberculosis in a Community Implementing Recommended Elements of Tuberculosis Control

• Published in: JAMA : the journal of the American Medical Association Vol. 283; no. 22; pp. 2968 - 2974
• Main Authors: Chin, Daniel P, Crane, Charles M, Diul, Mukadi Ya, Sun, Sumi J, Agraz, Rocio, Taylor, Sirlura, Desmond, Edward, Wise, Francie
• Format: Journal Article
• Language: English
• Published: Chicago, IL American Medical Association 14.06.2000
• Subjects: Adolescent; Adult; Aged; Bacterial diseases; Biological and medical sciences; Child; Cluster Analysis; Community; Contact Tracing; Epidemiology; Female; Human bacterial diseases; Humans; Infectious diseases; Male; Medical sciences; Middle Aged; Molecular Epidemiology; Mycobacterium tuberculosis; Mycobacterium tuberculosis - genetics; Public health; San Francisco - epidemiology; Tuberculosis; Tuberculosis - diagnosis; Tuberculosis - epidemiology; Tuberculosis - prevention & control; Tuberculosis - transmission; Tuberculosis and atypical mycobacterial infections; San Francisco; USA, California; Human; Lung disease; Respiratory disease; Pathogenesis; Lung; Mycobacterial infection; Epidemiology; Infection; Community acquired infection; Tuberculosis; Dissemination; Bacteriosis; Public health
• ISSN: 0098-7484; 1538-3598
• DOI: 10.1001/jama.283.22.2968

CONTEXT 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. DESIGN Population-based, molecular epidemiological study. SETTING Urban community in the San Francisco Bay area of California with recommended elements of TB control in place. PATIENTS 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. MAIN OUTCOME MEASURES 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.