Recent Transmission of Tuberculosis — United States, 2011–2014

<div><p>Tuberculosis is an infectious disease that may result from recent transmission or from an infection acquired many years in the past; there is no diagnostic test to distinguish the two causes. Cases resulting from recent transmission are particularly concerning from a public health standpoint. To describe recent tuberculosis transmission in the United States, we used a field-validated plausible source-case method to estimate cases likely resulting from recent transmission during January 2011–September 2014. We classified cases as resulting from either limited or extensive recent transmission based on transmission cluster size. We used logistic regression to analyze patient characteristics associated with recent transmission. Of 26,586 genotyped cases, 14% were attributable to recent transmission, 39% of which were attributable to extensive recent transmission. The burden of cases attributed to recent transmission was geographically heterogeneous and poorly predicted by tuberculosis incidence. Extensive recent transmission was positively associated with American Indian/Alaska Native (adjusted prevalence ratio [aPR] = 3.6 (95% confidence interval [CI] 2.9–4.4), Native Hawaiian/Pacific Islander (aPR = 3.2, 95% CI 2.3–4.5), and black (aPR = 3.0, 95% CI 2.6–3.5) race, and homelessness (aPR = 2.3, 95% CI 2.0–2.5). Extensive recent transmission was negatively associated with foreign birth (aPR = 0.2, 95% CI 0.2–0.2). Tuberculosis control efforts should prioritize reducing transmission among higher-risk populations.</p></div

Multivariable models for associations between patient characteristics and limited or extensive recent transmission.

<p>Multivariable models for associations between patient characteristics and limited or extensive recent transmission.</p

Frequency of patient characteristics among cases not attributed to recent transmission (N = 22,759) and attributed to recent transmission (N = 3,827).

<p>Frequency of patient characteristics among cases not attributed to recent transmission (N = 22,759) and attributed to recent transmission (N = 3,827).</p

Independent predictors of acquired resistance to isoniazid and rifamycins in multivariable regression analysis.

<p>Abbreviation: CI = confidence interval, DST = drug susceptibility test, DOT = directly observed therapy.</p

Map of states by proportion of cases attributed to extensive recent transmission—January 2011–September 2014.

<p>Map of states by proportion of cases attributed to extensive recent transmission—January 2011–September 2014.</p

Sociodemographic and clinical factors associated with acquired resistance to rifamycins (N = 4,005).

*<p>Regions defined by World Health Organization <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083006#pone.0083006-World3" target="_blank">[37]</a>.</p><p>Missing values not reported in table.</p><p>Abbreviations: PR = prevalence ratio, CI = confidence interval, DST = drug susceptibility test, AFB = acid-fast bacilli, DOT = directly observed therapy.</p

Associations between <i>M. tuberculosis</i> complex lineage and acquired resistance to isoniazid, rifamycins, second-line injectables, and fluoroquinolones.

*<p>Adjusted for HIV status.</p>†<p>Adjusted for homelessness, HIV status, initial resistance to isoniazid, site of disease, and administration of therapy.</p><p>Abbreviations: CI = confidence interval, – = no prevalence ratio calculated because no cases had acquired resistance.</p

Selection of cases included in analysis.

<p>Abbreviations: TB = tuberculosis, DST = drug susceptibility test, AR = acquired resistance.</p

Survival of patients on tuberculosis treatment by their HIV and ART status.

<p>Survival of patients on tuberculosis treatment by their HIV and ART status.</p

Bivariate and multivariable associations between patient characteristics and death among TB patients in Kenya.

<p>Bivariate and multivariable associations between patient characteristics and death among TB patients in Kenya.</p