Differences in Contributing Factors to Tuberculosis  Incidence in U.S.-born and Foreign-born Persons

Chin, Daniel P.; DeRiemer, Kathryn; Small, Peter M.; León, Alfredo Ponce de; Steinhart, Rachel; Schecter, Gisela; Daley, Charles L.; Moss, Andrew R.; Paz, E. Antonio; Jasmer, Robert M.; Agasino, Cristina B.; Hopewell, Philip C.

doi:10.1164/ajrccm.158.6.9804029

Cited by 123 publications

(71 citation statements)

References 32 publications

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“…In combination with sociological patterns of assortment, this low transmissibility might generate the kind of stable association between host and pathogen populations that we observe. This explanation is consistent with previous observations of very limited transmission from ethnically defined, foreign-born patient populations to U.S.-born individuals (42,43). However, the apparent longevity of the associations revealed by this study is surprising.…”

Section: Discussionsupporting

confidence: 93%

“…4. These clades are (16,44), (2,9,10,15,33,43,65,68,72,74), (4,14,23,57,86), (7,56,70), (28,58,84), (47, 55, 67, 69, 95, 97), (46, 79), (76, 83), (18,22,35,40,81), (38,60) where m is the number of terminal clades in the phylogeny, n k is the number of isolates in clade k, d ij is the number of deletions by which isolates i and j differ, and t ij is the number of bands by which the IS6110 fingerprints of isolates i and j differ.…”

Section: Methodsmentioning

confidence: 99%

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Stable association between strains of Mycobacterium tuberculosis and their human host populations

Hirsh

Tsolaki

DeRiemer

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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Mycobacterium tuberculosis is an important human pathogen in virtually every part of the world. Here we investigate whether distinct strains of M. tuberculosis infect different human populations and whether associations between host and pathogen populations are stable despite global traffic and the convergence of diverse strains of the pathogen in cosmopolitan urban centers. The recent global movement and transmission history of 100 M. tuberculosis isolates was inferred from a molecular epidemiologic study of tuberculosis that spans 12 years. Genetic relationships among these isolates were deduced from the distribution of large genomic deletions, which were identified by DNA microarray and confirmed by PCR and sequence analysis. Phylogenetic analysis of these deletions indicates that they are unique event polymorphisms and that horizontal gene transfer is extremely rare in M. tuberculosis. In conjunction with the epidemiological data, phylogenies reveal three large phylogeographic regions. A host's region of origin is predictive of the strain of tuberculosis he or she carries, and this association remains strong even when transmission takes place in a cosmopolitan urban center outside of the region of origin. Approximate dating of the time since divergence of East Asian and Philippine clades of M. tuberculosis suggests that these lineages diverged centuries ago. Thus, associations between host and pathogen populations appear to be highly stable.M ycobacterium tuberculosis is a global pathogen, killing 1.9 million people each year and infecting Ϸ2 billion people worldwide (1, 2). Although it is primarily a scourge of the developing world, tuberculosis affects virtually every nation and every ethnicity (2). In view of this ubiquity, an important question in understanding the epidemiology and basic disease biology of the current pandemic is whether there are geographically or ethnically defined human populations within which transmission of M. tuberculosis is relatively common but between which transmission is far more limited. Do global traffic and ''small world'' effects result in a single, panmictic population of M. tuberculosis, or is the pathogen population somehow subdivided, with genetically distinct varieties carried in distinct populations of human hosts?The answer to this basic question may have direct implications for the development and administration of tuberculosis vaccines. Genetic variability in the pathogen population, as in Plasmodium and Streptococcus pneumoniae, can render vaccines ineffective against certain strains or in certain geographic regions. There is substantial geographic variability in the efficacy of the world's current tuberculosis vaccine (3, 4), and the reasons for this variation are not yet well understood. Although it is possible that genetic differences among strains of M. tuberculosis play a role in the variable efficacy of bacillus Calmette-Guérin, actual associations between distinct strains of M. tuberculosis and their human host populations have not been demonstrated, and ...

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Section: Discussionsupporting

confidence: 93%

Section: Methodsmentioning

confidence: 99%

Stable association between strains of Mycobacterium tuberculosis and their human host populations

Hirsh

Tsolaki

DeRiemer

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

381

321

View full text Add to dashboard Cite

show abstract

“…Furthermore, we found that 57.9% of immigrants in mixed clusters were infected with TB strains that had already been identified in the native population. Our study shows a more extensive transmission between the two populations in Madrid than other authors have shown previously (3,9,22), even taking into account that in Madrid the period from arrival to the time of diagnosis of active TB was shorter than the parallel period in those studies. Probably, the sociocultural characteristics of immigrants coming to Spain, many of them sharing a common language with Spanish-born people, facilitate interactions between foreign-born people and the native population.…”

Section: Discussioncontrasting

confidence: 57%

Analysis of Changes in Recent Tuberculosis Transmission Patterns after a Sharp Increase in Immigration

et al. 2007

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We conducted a population-based molecular epidemiological study of tuberculosis (TB) in Madrid, Spain (2002 to 2004), to define transmission patterns and factors associated with clustering. We particularly focused on examining how the increase in TB cases among immigrants in recent years (2.8% in 1997 to 1999 to 36.2% during the current study) was modifying transmission patterns. Mycobacterium tuberculosis isolates obtained from patients living in nine districts of Madrid (1,459,232 inhabitants) were genotyped. The TB case rate among foreign-born people was three to four times that of Spanish-born people, and the median time from arrival to the onset of treatment was 22.4 months. During the study period, 227 (36.3%) patients were grouped in 64 clusters, and 115 (50.7%) of them were in 21 clusters with mixed Spanish-born and foreign-born patients. Three of the 21 mixed clusters accounted for 21.1% of clustered patients. Twenty-two of 38 (57.9%) immigrants in mixed clusters were infected with TB strains that had already been identified in the native population in 1997 to 1999, including the three most prevalent strains. Factors identified as independent predictors of clustering were homelessness (odds ratio [OR], 2.3; 95% confidence interval [95% CI], 1.2 to 4.5; P ‫؍‬ 0.011) and to be born in Spain (OR, 1.8; 95% CI, 1.2 to 2.6; P ‫؍‬ 0.002). The results indicated that (i) TB transmission was higher in Spanish-born people, associated mainly with homelessness, (ii) that foreign-born people were much less likely to be clustered, suggesting a higher percentage of infection before arriving in Spain, and (iii) that an extensive transmission between Spanish-and foreign-born populations, caused mainly by autochthonous strains, was taking place in Madrid.

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“…However, restriction fragment length polymorphism studies have detected relatively little TB transmission from foreign-born residents to the general population [3,17]. The estimated proportion of active TB cases among the native-born that can be attributed to transmission from the foreign-born may be as low as 2% [18] or 11% [19], or as much as 17% [16,[20][21][22]. In one USA study, foreign-born TB patients were more likely to have acquired TB from USA-born individuals than vice versa [20]!…”

Section: Impact Of Tb Among the Foreign-born Within Low-incidence Coumentioning

confidence: 99%

Cost-effectiveness of tuberculosis control strategies among immigrants and refugees

2005

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Today, in Western Europe, Canada and the USA, more than half of all new active tuberculosis (TB) cases occur among foreign-born migrants. This article examines the impact of migration from high TB-incidence to low TB-incidence countries, and compares the costeffectiveness of different TB control strategies.A Medline search was conducted to identify relevant English language publications prior to December 2003. Additional articles were identified from the reference lists from these publications.Despite the high proportion of active cases in low-incidence countries attributable to foreignborn residents, the public health impact is relatively low. Current chest radiograph screening programmes have little impact and are not cost-effective. Screening with sputum culture would improve cost-effectiveness marginally. Treatment of latent infection detected through screening with tuberculin skin testing or chest radiographs may require coercive measures to maximise impact and cost-effectiveness. In contrast, contact tracing, particularly within ethnic communities, appears to be more cost-efficient and less intrusive.In low-incidence countries, screening of migrants at entry has little overall impact and is not a very cost-effective tuberculosis control strategy. More effective alternatives include contact tracing delivered through primary care and increased investment in global tuberculosis control.

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Differences in Contributing Factors to Tuberculosis Incidence in U.S.-born and Foreign-born Persons

Cited by 123 publications

References 32 publications

Stable association between strains of Mycobacterium tuberculosis and their human host populations

Stable association between strains of Mycobacterium tuberculosis and their human host populations

Analysis of Changes in Recent Tuberculosis Transmission Patterns after a Sharp Increase in Immigration

Cost-effectiveness of tuberculosis control strategies among immigrants and refugees

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