Impact of Immigration on the Molecular Epidemiology of Tuberculosis in Rhode Island

Abstract

While foreign-born persons constitute only 11% of the population in the state of Rhode Island, they account for more than 65% of incident tuberculosis (TB) annually. We investigated the molecular-epidemiological differences between foreign-born and U.S.-born TB patients to estimate the degree of recent transmission and identify predictors of clustering. A total of 288 isolates collected from culture-confirmed TB cases in Rhode Island between 1995 and 2004 were fingerprinted by spoligotyping and 12-locus mycobacterial interspersed repetitive units. Of the 288 fingerprinted isolates, 109 (37.8%) belonged to 36 genetic clusters. Our findings demonstrate that U.S.-born patients, Hispanics, Asian/Pacific islanders, and uninsured patients were significantly more likely to be clustered. Recent transmission among the foreign-born population was restricted and occurred mostly locally, within populations originating from the same region. Nevertheless, TB transmission between the foreign-born and U.S.-born population should not be neglected, since 80% of the mixed clusters of foreign-and U.S.-born persons arose from a foreign-born source case. We conclude that timely access to routine screening and treatment for latent TB infection for immigrants is vital for disease elimination in Rhode Island.

A Field-Validated Approach Using Surveillance and Genotyping Data to Estimate Tuberculosis Attributable to Recent Transmission in the United States

“…It evaluates the same time frame for a plausible-source case for all cases, regardless of when during the study period the case was diagnosed. Unlike the n – 1 method (8), the commonly used approach to account for source cases (15, 16, 18, 19, 21), our plausible-source case approach does not assume that the first case in the cluster is the source case for every other case in the cluster. Rather, it considers plausible-source cases for each case individually, requiring that a plausible-source case have characteristics associated with infectiousness.…”

“…Three of the approaches, referred to here as geographic approaches, were based on geography and genotyping alone. The geographic units in these approaches have been previously used as the basis for published estimates of RT (14, 19–21). The fourth approach, the plausible-source case approach, is a novel approach we propose that is based on identifying a plausible-source case of transmission based on clinical and demographic factors, the time interval between cases, geography, and genotyping data.…”

“…As a result, estimates have varied dramatically, even across populations that would be expected to have similar rates of RT (15–19, 21, 26). Multiple factors affect genotype-based RT estimates, including the geographic unit over which clustering is defined (20), the time window of the study (26), and whether or not source cases are taken into account (27).…”

Tuberculosis – A global emergency: Tools and methods to monitor, understand, and control the epidemic with specific example of the Beijing lineage

“…Throughout in this paper, the order of MIRU loci is as follows: 12-loci MIRU patterns: MIRU 2,4,10,16,20,23,24,26,27, …”

Individual- and neighborhood-level contextual factors are associated with Mycobacterium tuberculosis transmission: genotypic clustering of cases in Michigan, 2004–2012

“…However, previous studies have also found both individual-level and neighborhood-level socio-demographic factors to be predictors of recent TB transmission. Individual-level socio-demographic characteristics such as younger age [8–10], minority race/ethnicity status [8,11], male sex [9,10], and being native-born [8,11–13] have been associated with recent TB transmission. Additionally, “known TB risk factors” as defined by the Centers for Disease Control and Prevention (CDC) surveillance forms [14], such as homelessness [8,9,13], incarceration [8], and drug use [13] have also been linked to recent transmission.…”