Tuberculosis Infection among Non-US-Born Persons and Persons ≥60 Years of Age, United States, 2019-2020.

We examined tuberculosis (TB) infection results for the United States from the 2019-2020 National Health and Nutrition Examination Survey. Over this period, 10% of non-US-born persons and 7% of those >60 years of age tested positive for TB infection. These results provide up-to-date information on TB infection among study subpopulations.

Validation of genotype cluster investigations for Mycobacterium tuberculosis: application results for 44 clusters from four heterogeneous United States jurisdictions.

BACKGROUND: Tracking the dissemination of specific Mycobacterium tuberculosis (Mtb) strains using genotyped Mtb isolates from tuberculosis patients is a routine public health practice in the United States. The present study proposes a standardized cluster investigation method to identify epidemiologic-linked patients in Mtb genotype clusters. The study also attempts to determine the proportion of epidemiologic-linked patients the proposed method would identify beyond the outcome of the conventional contact investigation. METHODS: The study population included Mtb culture positive patients from Georgia, Maryland, Massachusetts and Houston, Texas. Mtb isolates were genotyped by CDC's National TB Genotyping Service (NTGS) from January 2006 to October 2010. Mtb cluster investigations (CLIs) were conducted for patients whose isolates matched exactly by spoligotyping and 12-locus MIRU-VNTR. CLIs were carried out in four sequential steps: (1) Public Health Worker (PHW) Interview, (2) Contact Investigation (CI) Evaluation, (3) Public Health Records Review, and (4) CLI TB Patient Interviews. Comparison between patients whose links were identified through the study's CLI interviews (Step 4) and patients whose links were identified earlier in CLI (Steps 1-3) was conducted using logistic regression. RESULTS: Forty-four clusters were randomly selected from the four study sites (401 patients in total). Epidemiologic links were identified for 189/401 (47 %) study patients in a total of 201 linked patient-pairs. The numbers of linked patients identified in each CLI steps were: Step 1 - 105/401 (26.2 %), Step 2 - 15/388 (3.9 %), Step 3 - 41/281 (14.6 %), and Step 4 - 28/119 (30 %). Among the 189 linked patients, 28 (14.8 %) were not identified in previous CI. No epidemiologic links were identified in 13/44 (30 %) clusters. CONCLUSIONS: We validated a standardized and practical method to systematically identify epidemiologic links among patients in Mtb genotype clusters, which can be integrated into the TB control and prevention programs in public health settings. The CLI interview identified additional epidemiologic links that were not identified in previous CI. One-third of the clusters showed no epidemiologic links despite being extensively investigated, suggesting that some improvement in the interviewing methods is still needed.

Trends in tuberculosis - United States, 2013.

In 2013, a total of 9,588 new tuberculosis (TB) cases were reported in the United States, with an incidence rate of 3.0 cases per 100,000 population, a decrease of 4.2% from 2012. This report summarizes provisional TB surveillance data reported to CDC in 2013. Although case counts and incidence rates continue to decline, certain populations are disproportionately affected. The TB incidence rate among foreign-born persons in 2013 was approximately 13 times greater than the incidence rate among U.S.-born persons, and the proportion of TB cases occurring in foreign-born persons continues to increase, reaching 64.6% in 2013. Racial/ethnic disparities in TB incidence persist, with TB rates among non-Hispanic Asians almost 26 times greater than among non-Hispanic whites. Four states (California, Texas, New York, and Florida), home to approximately one third of the U.S. population, accounted for approximately half the TB cases reported in 2013. The proportion of TB cases occurring in these four states increased from 49.9% in 2012 to 51.3% in 2013. Continued progress toward TB elimination in the United States will require focused TB control efforts among populations and in geographic areas with disproportionate burdens of TB.

Association between tuberculin skin test result and clinical presentation of tuberculosis disease.

BACKGROUND: The tuberculin skin test (TST) is used to test for latent tuberculosis (TB) infection and support the diagnosis of active TB. However, little is known about the relationship between the TST result and the clinical presentation of TB disease. METHODS: We analyzed US TB surveillance data, 1993-2010, and used multinomial logistic regression to calculate the association between TST result (0-4 mm [negative], 5-9 mm, 10-14 mm, and ≥ 15 mm) and clinical presentation of disease (miliary, combined pulmonary and extrapulmonary, extrapulmonary only, non-cavitary pulmonary, and cavitary pulmonary). For persons with pulmonary disease, multivariate logistic regression was used to calculate the odds of having acid-fast bacilli (AFB) positive sputum. RESULTS: There were 64,238 persons with culture-confirmed TB included in the analysis, which was stratified by HIV status and birthplace (US- vs. foreign-born). Persons with a TST ≥ 15 mm were less likely to have miliary or combined pulmonary and extrapulmonary disease, but more likely to have cavitary pulmonary disease than non-cavitary pulmonary disease. Persons with non-cavitary pulmonary disease with a negative TST were significantly more likely to have AFB positive sputum. CONCLUSIONS: Clinical presentation of TB disease differed according to TST result and persons with a negative TST were more likely to have disseminated disease (i.e., miliary or combined pulmonary and extrapulmonary). Further study of the TST result may improve our understanding of the host-pathogen relationship in TB disease.

Use of tuberculosis genotyping for postoutbreak monitoring.

CONTEXT: Review of routinely collected tuberculosis genotyping results following a known outbreak is a potential mechanism to examine the effectiveness of outbreak control measures. OBJECTIVE: To assess differences in characteristics between outbreak and postoutbreak tuberculosis cases. DESIGN: Retrospective. SETTING: United States. PARTICIPANTS: All tuberculosis cases identified as a result of >5-person outbreaks investigated by the Centers for Disease Control and Prevention during 2003 to 2007 (original outbreak cases), and subsequent culture-positive tuberculosis cases with matching Mycobacterium tuberculosis genotypes reported in the same county during 2004 to 2008 (postoutbreak cases). MAIN OUTCOME MEASURE: Proportion of demographic, social, and clinical characteristics of tuberculosis outbreak cases compared to postoutbreak cases. SECONDARY: Proportion of demographic, social, and clinical characteristics of epidemiologically linked versus nonlinked cases. RESULTS: Six outbreaks with 111 outbreak cases and 110 postoutbreak cases were identified. Differences between outbreak and postoutbreak cases were gender (69% vs 85% male; P < .01), birth origin (3% vs 11% foreign-born; P = .02), disease severity (48% vs 62% sputum smear-positive; P = .04), homelessness (38% vs 51%; P = .05), and injection drug use (4% vs 11%; P = .04). For 5 of the 6 outbreaks, the status of epidemiologic relationships among postoutbreak cases was available (n = 89). The postoutbreak cases with a known epidemiologic link to the original outbreak were in younger persons (aged 39 vs 47 years; P < .01), and a larger proportion reported injection drug use (18% vs 4%; P = .04) or noninjection drug use (44% vs 18%; P < .01) than those without a reported link. CONCLUSIONS: Health jurisdictions can utilize genotyping data to monitor and define the characteristics of postoutbreak cases related to the original outbreak.

Outbreak of tuberculosis among Guatemalan immigrants in rural Minnesota, 2008.

OBJECTIVES: We described the outbreak investigation and control measures after the Minnesota Department of Health identified a cluster of tuberculosis (TB) cases among Guatemalan immigrants within three rural Minnesota counties in August 2008. METHODS: TB cases were diagnosed by tuberculin skin test followed by chest radiography and sputum testing for Mycobacterium tuberculosis (M. tuberculosis). We reviewed medical records, interviewed patients, and completed a contact investigation for each infectious case. We used isolate genotyping to confirm epidemiologic links between cases. RESULTS: The index case was a six-month-old U.S.-born male with Guatemalan parents. Although he experienced four months of cough and fever, TB was not considered at two medical visits but was diagnosed upon hospitalization in May 2008. The presumed source of infection was a Guatemalan male aged 25 years who sang in a band that practiced in the infant's house and whose pulmonary TB was diagnosed at hospitalization in June 2008, despite his having sought medical attention for symptoms seven months earlier. Among the 16 identified TB cases, 14 were outbreak-related. Three genetically distinct M. tuberculosis strains circulated. Of 150 contacts of the singer, 62 (41%) had latent TB infection and 13 (9%), including 10 children, had TB disease. CONCLUSIONS: In this outbreak, delayed diagnoses contributed to M. tuberculosis transmission. Isolate genotyping corroborated the social links between outbreak-related patients. More timely diagnosis of TB among immigrants and their children can prevent TB transmission among communities in rural, low-incidence areas that might have limited resources for contact investigations.

Estimated Latent Tuberculosis Infection Prevalence and Tuberculosis Reactivation Rates Among Non-U.S.-Born Residents in the United States, from the 2011-2012 National Health and Nutrition Examination Survey.

Increased testing and treatment of latent tuberculosis infection (LTBI) among US-residents who were born (or lived) in countries with high rates of TB can hasten progress toward TB elimination. We calculated LTBI prevalence using QuantiFERON®-TB Gold In-Tube results from the 2011 to 2012 National Health and Nutrition Examination Survey (NHANES). LTBI prevalence was highest for persons born in India (31.7%, 95% confidence interval [21.2, 44.5]). Non-Hispanic white persons had the lowest LTBI prevalence (6.3% [1.9, 18.9]). TB reactivation rate, defined as the number of TB cases not associated with recent transmission per 100 person-years of life with LTBI, was highest for persons born in Vietnam [0.183 (0.117, 0.303)]. Reactivation rates were lower among persons who had resided in the United States for ≥ 10 years than among those who had resided for < 10 years. Results among high risk populations can guide LTBI targeted testing and treatment among non-U.S.-born residents.

Self-reported Engagement in Care among U.S. Residents with Latent Tuberculosis Infection: 2011-2012.

Rationale: A central strategy of tuberculosis (TB) control in the United States is reducing the burden of latent TB infection (LTBI) through targeted testing and treatment of persons with untreated LTBI. Objectives: The objective of the study was to provide estimates of and risk factors for engagement in LTBI care in the overall U.S. population and among specific risk groups. Methods: We used nationally representative data from 7,080 participants in the 2011-2012 National Health and Nutrition Examination Survey. Engagement in LTBI care was assessed by estimating the proportion with a history of testing, diagnosis, treatment initiation, and treatment completion. Weighted methods were used to account for the complex survey design and to derive national estimates. Results: Only 1.4 million (10%) of an estimated 14.0 million individuals with an LTBI had previously completed treatment. Of the 12.6 million who did not complete LTBI treatment, 3.7 million (29%) had never been tested and 7.2 million (57%) received testing but had no history of diagnosis. High-risk groups showed low levels of engagement, including contacts of individuals with TB and persons born outside the United States. Conclusions: There is a reservoir of more than 12 million individuals in the United States who may be at risk for progression to TB disease and potential transmission. TB control programs and community providers should consider focused efforts to increase testing, diagnosis, and treatment for LTBI.

Public health response to a multidrug-resistant tuberculosis outbreak among Guatemalans in Tennessee, 2007.

BACKGROUND: In June 2007, the Tennessee Department of Health notified the Centers for Disease Control and Prevention of four multidrug-resistant tuberculosis (MDR TB) cases in individuals of Guatemalan descent, and requested onsite epidemiologic assistance to investigate this outbreak. METHODS: A case was defined as either culture-confirmed MDR TB with a drug-susceptibility pattern closely resembling that of the index case, or a clinical diagnosis of active TB disease and corroborated contact with a person with culture-confirmed MDR TB. Medical records were reviewed, and patients and their contacts were interviewed. RESULTS: Five secondary TB cases were associated with the index case. Of 369 contacts of the index case, 189 (51%) were evaluated. Of those, 97 (51%) had positive tuberculin skin test (TST) results, 79 (81%) began therapy for latent TB infection (LTBI), and 38 (48%) completed LTBI therapy. CONCLUSION: Despite consistent follow up by public health officials, a low proportion of patients diagnosed with LTBI completed therapy. Clinicians and public health practitioners who serve immigrant communities should be vigilant for MDR TB.

Towards Unified Data Exchange Formats for Reporting Molecular Drug Susceptibility Testing.

BACKGROUND: With the rapid development of new advanced molecular detection methods, identification of new genetic mutations conferring pathogen resistance to an ever-growing variety of antimicrobial substances will generate massive genomic datasets for public health and clinical laboratories. Keeping up with specialized standard coding for these immense datasets will be extremely challenging. This challenge prompted our effort to create a common molecular resistance Logical Observation Identifiers Names and Codes (LOINC) panel that can be used to report any identified antimicrobial resistance pattern. OBJECTIVE: To develop and utilize a common molecular resistance LOINC panel for molecular drug susceptibility testing (DST) data exchange in the U.S. National Tuberculosis Surveillance System using California Department of Public Health (CDPH) and New York State Department of Health as pilot sites. METHODS: We developed an interface and mapped incoming molecular DST data to the common molecular resistance LOINC panel using Health Level Seven (HL7) v2.5.1 Electronic Laboratory Reporting (ELR) message specifications through the Orion Health™ Rhapsody Integration Engine v6.3.1. RESULTS: Both pilot sites were able to process and upload/import the standardized HL7 v2.5.1 ELR messages into their respective systems; albeit CDPH identified areas for system improvements and has focused efforts to streamline the message importation process. Specifically, CDPH is enhancing their system to better capture parent-child elements and ensure that the data collected can be accessed seamlessly by the U.S. Centers for Disease Control and Prevention. DISCUSSION: The common molecular resistance LOINC panel is designed to be generalizable across other resistance genes and ideally also applicable to other disease domains. CONCLUSION: The study demonstrates that it is possible to exchange molecular DST data across the continuum of disparate healthcare information systems in integrated public health environments using the common molecular resistance LOINC panel.

Design and Implementation of Data Exchange Formats for Molecular Detection of Drug-Resistant Tuberculosis.

Drug-resistant tuberculosis (TB) remains a public health threat to the United States and worldwide control of TB. Rapid and reliable drug susceptibility testing (DST) is essential for aiding clinicians in selecting an optimal treatment regimen for TB patients and to prevent ongoing transmission. Growth-based DST results for culture-confirmed cases are routinely reported to the U.S. Centers for Disease Control and Prevention through the National TB Surveillance System (NTSS). However, the NTSS currently lacks the capacity and functionality to accept laboratory results from advanced molecular methods that detect mutations associated with drug resistance. The objective of this study is to design and implement novel comprehensive data exchange formats that utilize the Health Level Seven (HL7) version 2.5.1 messaging hierarchy to capture, store, and monitor molecular DST data, thereby, improving the quality of data, specifications and exchange formats within the NTSS as well as ensuring full reporting of drug-resistant TB.

Development of a Surveillance Definition for United States-Mexico Binational Cases of Tuberculosis.

OBJECTIVES: Consistently collected binational surveillance data are important in advocating for resources to manage and treat binational cases of tuberculosis (TB). The objective of this study was to develop a surveillance definition for binational (United States-Mexico) cases of TB to assess the burden on US TB program resources. METHODS: We collaborated with state and local TB program staff members in the United States to identify characteristics associated with binational cases of TB. We collected data on all cases of TB from 9 pilot sites in 5 states (Arizona, California, Colorado, New Mexico, and Texas) during January 1-June 30, 2014, that had at least 1 binational characteristic (eg, "crossed border while on TB treatment" and "received treatment in another country, coordinated by an established, US-funded, binational TB program"). A workgroup of US state, local, and federal partners reviewed results and used them to develop a practical surveillance definition. RESULTS: The pilot sites reported 87 cases of TB with at least 1 binational characteristic during the project period. The workgroup drafted a proposed surveillance definition to include 2 binational characteristics: "crossed border while on TB treatment" (34 of 87 cases, 39%) and "received treatment in another country, coordinated by an established, US-funded, binational TB program" (26 of 87 cases, 30%). Applying the new proposed definition, 39 of 87 pilot cases of TB (45%) met the definition of binational. CONCLUSION: Input from partners who were responsible for the care and treatment of patients who cross the United States-Mexico border was crucial in defining a binational case of TB.

Sociodemographic and Clinical Risk Factors Associated With Tuberculosis Mortality in the United States, 2009-2013.

OBJECTIVES: The objectives of our study were (1) to determine risk factors associated with tuberculosis (TB)-specific and non-TB-specific mortality among patients with TB and (2) to examine whether risk factors for TB-specific mortality differed from those for non-TB-specific mortality. METHODS: We obtained data from the National Tuberculosis Surveillance System and included all patients who had TB between 2009 and 2013 in the United States and its territories. We used multinomial logistic regression analysis to determine the adjusted odds ratio (aOR) of each risk factor for TB-specific and non-TB-specific mortality. RESULTS: Of 52 175 eligible patients with TB, 1404 died from TB, and 2413 died from other causes. Some of the risk factors associated with the highest odds of TB-specific mortality were multidrug-resistant TB diagnosis (aOR = 3.42; 95% CI, 1.95-5.99), end-stage renal disease (aOR = 3.02; 95% CI, 2.23-4.08), human immunodeficiency virus infection (aOR = 2.63; 95% CI, 2.02-3.42), age 45-64 years (aOR = 2.57; 95% CI, 2.01-3.30) or age ≥65 years (aOR = 5.76; 95% CI, 4.37-7.61), and immunosuppression (aOR = 2.20; 95% CI, 1.71-2.83). All of these risk factors except multidrug-resistant TB were also associated with increased odds of non-TB-specific mortality. CONCLUSION: TB patients with certain risk factors have an elevated risk of TB-specific mortality and should be monitored before, during, and after treatment. Identifying the predictors of TB-specific mortality may help public health authorities determine which subpopulations to target and where to allocate resources.

Tuberculosis Test Usage and Medical Expenditures from Outpatient Insurance Claims Data, 2013.

OBJECTIVE: To evaluate TB test usage and associated direct medical expenditures from 2013 private insurance claims data in the United States (US). METHODS: We extracted outpatient claims for TB-specific and nonspecific tests from the 2013 MarketScan® commercial database. We estimated average expenditures (adjusted for claim and patient characteristics) using semilog regression analyses and compared them to the Centers for Medicare and Medicaid Services (CMS) national reimbursement limits. RESULTS: Among the TB-specific tests, 1.4% of the enrollees had at least one claim, of which the tuberculin skin test was most common (86%) and least expensive ($9). The T-SPOT® was the most expensive among the TB-specific tests ($106). Among nonspecific TB tests, the chest radiograph was the most used test (78%), while chest computerized tomography was the most expensive ($251). Adjusted average expenditures for the majority of tests (≈74%) were above CMS limits. We estimated that total United States medical expenditures for the employer-based privately insured population for TB-specific tests were $53.0 million in 2013, of which enrollees paid 17% ($9 million). CONCLUSIONS: We found substantial differences in TB test usage and expenditures. Additionally, employer-based private insurers and enrollees paid more than CMS limits for most TB tests.

Evaluation of 24-locus MIRU-VNTR genotyping in Mycobacterium tuberculosis cluster investigations in four jurisdictions in the United States, 2006-2010.

The U.S. Centers for Disease Control and Prevention (CDC) uses a combination of spacer oligonucleotide typing (spoligotyping) and mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) analyses as part of the National TB Genotyping Service (NTGS). The NTGS expansion from 12-locus MIRU-VNTR (MIRU12) to 24-locus MIRU-VNTR (MIRU24) in 2009 enhanced the ability to discriminate Mycobacterium tuberculosis strains. In the current study, we investigated the MIRU24 concordance among epidemiologic-linked tuberculosis (TB) patients in four U.S. health jurisdictions. We also evaluated the programmatic benefits of combining MIRU24 and spoligotyping with epidemiologic evidence in identifying potential recent TB transmission. We examined 342 TB patients in 42 spoligotype/MIRU12 (PCRType) clusters (equivalent to 46 spoligotype/MIRU24 [GENType] clusters) to identify epidemiologic links among cases. GENType clusters, when compared to PCRType clusters, had 12 times higher odds of epidemiologic links being identified if patients were younger than 25 years and 3 times higher odds if patients resided in the same zip code, or had HIV infection. Sixty (18%) fewer PCRType-clustered patients would need investigations if clusters are defined using GENType instead of PCRType. An important advantage of defining clusters by MIRU24 is resource savings related to the reduced number of clustered cases needing investigation.

Is agricultural activity linked to the incidence of human West Nile virus?

BACKGROUND: West Nile virus (WNV) has spread throughout the contiguous United States. During the 2002-2003 period, there were 14,023 laboratory-confirmed human cases of WNV in 45 states and 541 associated deaths. Factors that affect case distribution are poorly understood. This study assessed the relationship of environmental factors and agricultural activity with the presence of human WNV cases. METHODS: County-level data were collected that included 2002 and 2003 WNV surveillance data, temperature, dairy revenue, precipitation, total irrigated acres, and total crop revenue. Logistic regression models were used to determine which risk factors were significantly associated with WNV human cases. RESULTS: Significant independent predictors for counties with human WNV cases were population (odds ratio [OR]=1.20, p<0.0001); higher average daily temperature in April through October (OR=1.19 for each additional degree Fahrenheit, p<0.0001); and total crop sales (OR=1.14 (p<0.001). The ORs for these predictors increased in an analysis of counties with ten or more cases. CONCLUSIONS: Higher temperature and farming activity may be strongly associated with the incidence of human WNV infection. Larger studies of more agricultural centers are warranted to determine which environmental factors increase the risk of human infection and how these infections can be prevented.

Excess Alcohol Use and Death among Tuberculosis Patients in the United States, 1997-2012.

RATIONALE: Excess alcohol use (EAU) is associated with adverse TB treatment outcomes. OBJECTIVE: We investigated the relationship between EAU and death among TB patients 15 years and older prescribed anti-TB treatment in the United States. DESIGN: Using data reported to the National Tuberculosis Surveillance System for 1997-2012, we calculated adjusted odds ratios and excess attributable risk percent for death among TB patients with reported EAU. RESULTS: EAU was associated with death among patients younger than 65. The excess attributable risk percent for death among those with reported EAU for those younger than 65 was >35%. CONCLUSIONS: Interventions to reduce EAU in patients <65 years may reduce deaths.

IFN-γ Release Assay Result Is Associated with Disease Site and Death in Active Tuberculosis.

RATIONALE: The IFN-γ release assays and tuberculin skin tests are used to support the diagnosis of both latent and active tuberculosis. However, we previously demonstrated that a negative tuberculin test in active tuberculosis is associated with disseminated disease and death. It is unknown whether the same associations exist for IFN-γ release assays. OBJECTIVES: To determine the association between these tests and site of tuberculosis and death among persons with active tuberculosis. METHODS: We analyzed IFN-γ release assays and tuberculin test results for all persons with culture-confirmed tuberculosis reported to the U.S. National Tuberculosis Surveillance System from 2010 to 2014. We used logistic regression to calculate the association between these tests and site of disease and death. MEASUREMENTS AND MAIN RESULTS: A total of 24,803 persons with culture-confirmed tuberculosis had either of these test results available for analysis. Persons with a positive tuberculin test had lower odds of disseminated disease (i.e., miliary or combined pulmonary and extrapulmonary disease), but there was no difference in the odds of disseminated disease with a positive IFN-γ release assay. However, persons who were positive to either of these tests had lower odds of death. An indeterminate IFN-γ release assay result was associated with greater odds of both disseminated disease and death. CONCLUSIONS: Despite perceived equivalence in clinical practice, IFN-γ release assays and tuberculin test results have different associations with tuberculosis site, yet similar associations with the risk of death. Furthermore, an indeterminate IFN-γ release assay result in a person with active tuberculosis is not unimportant, and rather carries greater odds of disseminated disease and death. Prospective study may improve our understanding of the underlying mechanisms by which these tests are associated with disease localization and death.

Tuberculosis Infection in the United States: Prevalence Estimates from the National Health and Nutrition Examination Survey, 2011-2012.

BACKGROUND: Reexamining the prevalence of persons infected with tuberculosis (TB) is important to determine trends over time. In 2011-2012 a TB component was included in the National Health and Nutrition Examination Survey (NHANES) to estimate the reservoir of persons infected with TB. METHODS: Civilian, noninstitutionalized U.S. population survey participants aged 6 years and older were interviewed regarding their TB history and eligibility for the tuberculin skin test (TST) and interferon gamma release assay (IGRA) blood test. Once eligibility was confirmed, both tests were conducted. Prevalence and numbers of TST positive (10 mm or greater), IGRA positive, and both TST and IGRA positive were calculated by adjusting for the complex survey design after applying corrections for item nonresponse and digit preference in TST induration measurements. To examine TST positivity over time, data from NHANES 1999-2000 were reanalyzed using the same statistical methods. The TST was performed using Tubersol, a commercially available purified protein derivative (PPD), rather than PPD-S, which was the antigen used in NHANES 1999-2000. Prior patient history of TB vaccination was not collected in this study nor were patients examined for the presence of a Bacillus of Calmette and Guerin (BCG) vaccine scar. RESULTS: For NHANES 2011-2012, TST and IGRA results were available for 6,128 (78.4%) and 7,107 (90.9%) eligible participants, respectively. There was no significant difference between the percentage of the U.S. population that was TST positive in 2011-2012 (4.7% [95% CI 3.4-6.3]; 13,276,000 persons) compared with 1999-2000 (4.3%; 3.5-5.3). In 2011-2012 the percentage that was IGRA positive was 5.0% (4.2-5.8) and double TST and IGRA positivity was 2.1% (1.5-2.8). The point estimate of IGRA positivity prevalence in foreign-born persons (15.9%; 13.5-18.7) was lower than for TST (20.5%; 16.1-25.8) in 2011-2012. The point estimate of IGRA positivity prevalence in U.S.-born persons (2.8%; 2.0-3.8) was higher than for TST (1.5%; 0.9-2.6). CONCLUSIONS: No statistically significant decline in the overall estimated prevalence of TST positivity was detected from 1999-2000 to 2011-2012. The prevalence of TB infection, whether measured by TST or IGRA, remains lower among persons born in the United States compared with foreign-born persons.

A tuberculosis outbreak fueled by cross-border travel and illicit substances: Nevada and Arizona.

OBJECTIVES: From May 2006 to August 2008, the Southern Nevada Health District identified eight tuberculosis (TB) cases in six adults and two children in a Hispanic community. We conducted an outbreak investigation to determine the extent of TB transmission and prevent additional cases. METHODS: We investigated TB cases in Nevada and Arizona with the outbreak genotype or cases with suspected epidemiologic links to this cluster but without genotyping data. We reviewed medical records and interviewed patients and contacts. Subsequently, genotype surveillance was conducted for approximately four years to monitor additional outbreak-related cases. RESULTS: Eight outbreak cases were identified among six adults and two children. All patients were Hispanic and five were U.S.-born. The index patient was diagnosed while detained in Immigration and Customs Enforcement custody but deported before treatment completion. He was lost to follow-up for two years, during which time he served as the source for six secondary TB cases, including his own child. Along with the index patient, five patients reportedly engaged in the sale or use of methamphetamine. Follow-up surveillance in the two states identified eight additional cases with the outbreak genotype; three had epidemiologic links to the index case. CONCLUSIONS: We found that incomplete TB treatment led to extensive TB transmission. We recommend thorough discharge planning and active measures to ensure continuity of care and TB treatment completion for people in custody at higher risk for loss to follow-up, which likely includes those engaged in the sale or use of illicit substances.