摘要：Objectives. We investigated a cluster of tuberculosis (TB) cases among persons using methamphetamines in Snohomish County, Washington, to determine the extent of the outbreak, examine whether methamphetamine use contributed to TB transmission, and implement strategies to prevent further infections. Methods. We screened contacts to find and treat persons with TB disease or infection. We then formed a multidisciplinary team to engage substance abuse services partners and implement outreach strategies including novel methods for finding contacts and a system of incentives and enablers to promote finding, screening, and treating patients with TB and their infected contacts. Results. We diagnosed and completed treatment with 10 persons with TB disease. Eight of 9 adult patients and 67% of their adult contacts reported using methamphetamines. Of the 372 contacts, 319 (85.8%) were screened, 80 (25.1%) were infected, 71 (88.8%) started treatment for latent infection, and 57 (80.3%) completed treatment for latent infection. Conclusions. Collaborative approaches integrating TB control, outreach, incentives, and enablers resulted in high rates of treatment adherence and completion among patients and infected contacts. TB control programs should collaborate with substance abuse programs to address addiction, overcome substance abuse–related barriers to treatment, treat TB, and prevent ongoing transmission. Illegal drug use is a risk factor for tuberculosis (TB). 1 Numerous studies have documented that alcohol abuse and illegal drug use (hereafter referred to as substance abuse) are factors that contribute to TB transmission and act as barriers to TB control and prevention. 2 – 8 Persons who abuse substances are less likely to seek medical care 9 , 10 and initiate, adhere to, and complete treatment for latent TB infection (LTBI) 11 – 13 or TB disease. 14 – 16 Nearly 1 out of every 3 US-born persons with TB who is aged older than 15 years abuses substances. 17 Substance abuse among persons with TB is important to public health because it is associated with sputum-smear positivity at diagnosis and failure to complete treatment of TB, both indicators of increased transmission. 17 Additionally, substance abuse often takes place in enclosed spaces with poor ventilation and high volumes of human traffic, potentially increasing the likelihood of TB transmission. 17 TB control programs have been slow to engage the substance abuse treatment community in collaboratively addressing substance abuse–fueled transmission of TB. 10 , 18 We are not aware of national guidelines that specifically address the control of TB transmission among populations that abuse alcohol and use illegal drugs. Our review of the scientific literature indicates that this is the first report documenting methamphetamine use as a barrier to controlling TB transmission. In 2006, the incidence of TB disease in Snohomish County, Washington, was 3.8 cases per 100 000 persons; the incidence of TB disease for the state of Washington was 4.1 per 100 000 persons. 19 From August 2005 through January 2006, the Snohomish Health District TB Control Program detected an emerging cluster of 6 persons with TB. Five of the 6 persons were known to spend time together (i.e., they were socially linked) and reported using methamphetamines. The recent clustering of these persons in time and space, along with matching genotype patterns of M. tuberculosis , suggested recent transmission of TB. 20 Initial attempts to identify contacts of the cluster (i.e., persons exposed to and potentially infected by the original 6 persons with TB) were unsuccessful. Even after repeated interviews, patients refused or remained reluctant to name their contacts. Local TB control staff suspected that this reluctance was related to the patients' use of methamphetamines and their unwillingness to provide names of persons with whom they used illegal substances. To address the substance abuse–related barriers to controlling the outbreak, we expanded our epidemiological investigation and TB control efforts to include alternative measures to find additional persons with TB, provide treatment of these persons, identify and screen their contacts, and provide treatment to those who tested positive for LTBI.
