摘要：Objectives. We evaluated a strategy for preventing tuberculosis (TB) in communities most affected by it. Methods. In 1996, we mapped reported TB cases (1985–1995) and positive tuberculin skin test (TST) reactors (1993–1995) in Smith County, Texas. We delineated the 2 largest, densest clusters, identifying 2 highest-incidence neighborhoods (180 square blocks, 3153 residents). After extensive community preparation, trained health care workers went door-to-door offering TST to all residents unless contraindicated. TST-positive individuals were escorted to a mobile clinic for radiography, clinical evaluation, and isoniazid preventive treatment (IPT) as indicated. To assess long-term impact, we mapped all TB cases in Smith County during the equivalent time period after the project. Results. Of 2258 eligible individuals, 1291 (57.1%) were tested, 229 (17.7%) were TST positive, and 147 were treated. From 1996 to 2006, there were no TB cases in either project neighborhood, in contrast with the preintervention decade and the continued occurrence of TB in the rest of Smith County. Conclusions. Targeting high-incidence neighborhoods for active, community-based screening and IPT may hasten TB elimination in the United States. According to a 1999–2000 tuberculin skin test (TST) survey, an estimated 4.2% of the US population—approximately 11 million people—had latent Mycobacterium tuberculosis infection (LTBI). 1 Reactivation of LTBI accounts for an estimated 70% of incident tuberculosis (TB) disease in the United States. 2,3 Eliminating TB in the United States will require preventing these cases. Treating LTBI with 6 to 12 months of isoniazid can substantially reduce TB incidence. 2,4–7 But how can 11 million individuals be identified and treated without testing the entire population? Testing for LTBI in the general population is not recommended because the predictive value of a positive TST under conditions of low prevalence is poor, and skin testing should be limited to persons at high risk. 2,8,9 Moreover, active screening and preventive treatment programs typically fail because of high rates of nonparticipation and attrition at each step of the process. The keys to active, community-based screening and preventive treatment would be to target high-risk populations with an efficient strategy, maximize participation, and minimize losses to follow-up so that the entire process becomes cost-effective. Many local health departments map cases of communicable diseases in their communities, displaying wall-mounted maps with color-coded pins indicating each case. Dense clusters of pins identify the hardest-hit neighborhoods. The modern version of this venerable practice involves use of a computerized geographic information system (GIS). We hypothesized that this information could identify neighborhoods at high risk of TB. If TB concentrates in specific neighborhoods, persisting over many years, then cases will likely continue occurring in these same neighborhoods. Targeting these neighborhoods with screening and prevention programs should prevent future TB cases. Using a GIS, we identified 2 high-risk neighborhoods in Smith County, Texas, and conducted a door-to-door screening and preventive treatment project. Ten years later, we assessed the impact of this strategy by comparing TB incidence in the target neighborhoods before and after the project with TB incidence in the rest of the county.
