Foreign-born Tuberculosis Research Articles

The effectiveness of primary care based risk stratification for targeted latent tuberculosis infection screening in recent immigrants to the UK: a retrospective cohort study

BackgroundMost UK tuberculosis (TB) cases occur in immigrants from high TB incidence areas, implicating reactivation of imported latent TB infection (LTBI). Strategies to identify and treat immigrant LTBI in primary...

Tuberculosis among the homeless, United States, 1994–2010

1) To describe homeless persons diagnosed with tuberculosis (TB) during the period 1994-2010, and 2) to estimate a TB incidence rate among homeless persons in the United States. TB cases reported to the National Tuberculosis Surveillance System were analyzed by origin of birth. Incidence rates were calculated using the US Department of Housing and Urban Development homeless population estimates. Analysis of genotyping results identified clustering as a marker for transmission among homeless TB patients. Of 270,948 reported TB cases, 16,527 (6%) were homeless. The TB incidence rate among homeless persons ranged from 36 to 47 cases per 100,000 population in 2006-2010. Homeless TB patients had over twice the odds of not completing treatment and of belonging to a genotype cluster. US- and foreign-born homeless TB patients had respectively 8 and 12 times the odds of substance abuse. Compared to the general population, homeless persons had an approximately 10-fold increase in TB incidence, were less likely to complete treatment and more likely to abuse substances. Public health outreach should target homeless populations to reduce the excess burden of TB in this population.

Predicting U.S. Tuberculosis Case Counts through 2020

In 2010, foreign-born persons accounted for 60% of all tuberculosis (TB) cases in the United States. Understanding which national groups make up the highest proportion of TB cases will assist TB control programs in concentrating limited resources where they can provide the greatest impact on preventing transmission of TB disease. The objective of our study was to predict through 2020 the numbers of U.S. TB cases among U.S.-born, foreign-born and foreign-born persons from selected countries of birth. TB case counts reported through the National Tuberculosis Surveillance System from 2000–2010 were log-transformed, and linear regression was performed to calculate predicted annual case counts and 95% prediction intervals for 2011–2020. Data were analyzed in 2011 before 2011 case counts were known. Decreases were predicted between 2010 observed and 2020 predicted counts for total TB cases (11,182 to 8,117 [95% prediction interval 7,262–9,073]) as well as TB cases among foreign-born persons from Mexico (1,541 to 1,420 [1,066–1,892]), the Philippines (740 to 724 [569–922]), India (578 to 553 [455–672]), Vietnam (532 to 429 [367–502]) and China (364 to 328 [249–433]). TB cases among persons who are U.S.-born and foreign-born were predicted to decline 47% (4,393 to 2,338 [2,113–2,586]) and 6% (6,720 to 6,343 [5,382–7,476]), respectively. Assuming rates of declines observed from 2000–2010 continue until 2020, a widening gap between the numbers of U.S.-born and foreign-born TB cases was predicted. TB case count predictions will help TB control programs identify needs for cultural competency, such as languages and interpreters needed for translating materials or engaging in appropriate community outreach.

Examining the Impact of Patient Characteristics and Symptomatology on Knowledge, Attitudes, and Beliefs Among Foreign-born Tuberculosis Cases in the US and Canada

Foreign-born individuals represent the majority of TB cases in the US/Canada. Little is known about their TB knowledge, attitudes, and beliefs (KAB). Cross-sectional survey was conducted in 22 sites in the US/Canada among foreign-born adults with active TB. Multiple regression was used to examine KAB factors against covariates. Of 1,475 participants interviewed, most answered the six knowledge items correctly. Significant predictors of correct knowledge included region of origin, education, income, age, visa status, place of diagnosis, BCG vaccination, and TB symptoms. Significant predictors of higher perceived risk/stigma scores included region of origin, age, place of diagnosis, English fluency, time in the US/Canada, TB symptoms, and household rooms. This study examines associations between TB KAB and patient and disease characteristics in foreign-born individuals in the US/Canada. The findings call for improved health education, along with efforts to reduce stigma and enhance realistic risk assessments.

Admixed Phylogenetic Distribution of Drug Resistant Mycobacterium tuberculosis in Saudi Arabia

BackgroundThe phylogeographical structure of Mycobacterium tuberculosis is generally bimodal in low tuberculosis (TB) incidence countries, where genetic lineages of the isolates generally differ with little strain clustering between autochthonous and foreign-born TB patients. However, less is known on this structure in Saudi Arabia—the most important hub of human migration as it hosts a total population of expatriates and pilgrims from all over the world which is equal to that of its citizens.MethodologyWe explored the mycobacterial phylogenetic structure and strain molecular clustering in Saudi Arabia by genotyping 322 drug-resistant clinical isolates collected over a 12-month period in a national drug surveillance survey, using 24 locus-based MIRU-VNTR typing and spoligotyping.Principal FindingsIn contrast to the cosmopolitan population of the country, almost all the known phylogeographic lineages of M. tuberculosis complex (with noticeable exception of Mycobacterium africanum/West-African 1 and 2) were detected, with Delhi/CAS (21.1%), EAI (11.2%), Beijing (11.2%) and main branches of the Euro-American super-lineage such as Ghana (14.9%), Haarlem (10.6%) and Cameroon (7.8%) being represented. Statistically significant associations of strain lineages were observed with poly-drug resistance and multi drug resistance especially among previously treated cases (p value of < = 0.001 for both types of resistance), with relative over-representation of Beijing strains in the latter category. However, there was no significant difference among Saudi and non-Saudi TB patients regarding distribution of phylogenetic lineages (p = 0.311). Moreover, 59.5% (22/37) of the strain molecular clusters were shared between the Saudi born and immigrant TB patients.ConclusionsSpecific distribution of M. tuberculosis phylogeographic lineages is not observed between the autochthonous and foreign-born populations. These observations might reflect both socially favored ongoing TB transmission between the two population groups, and historically deep-rooted, prolonged contacts and trade relations of the peninsula with other world regions. More vigorous surveillance and strict adherence to tuberculosis control policies are urgently needed in the country.

P51 Reduced Effectiveness of the Primary-Care Registry For Targeted LTBI Screening of High Risk Immigrants with HIV Co-Infection

IntroductionThe impact of screening for latent tuberculosis infection (LTBI) in immigrants for tuberculosis (TB) prevention in the UK is dependent on effective strategies for identifying at-risk groups. Here we investigate...

Prevalence of Anti-Tuberculosis Drug Resistance in Foreign-Born Tuberculosis Cases in the U.S. and in Their Countries of Origin

BackgroundForeign-born individuals comprise >50% of tuberculosis (TB) cases in the U.S. Since anti-TB drug resistance is more common in most other countries, when evaluating a foreign-born individual for TB, one must consider the risk of drug resistance. Naturally, clinicians query The Global Project on Anti-tuberculosis Drug Resistance Surveillance (Global DRS) which provides population-based data on the prevalence of anti-TB drug resistance in 127 countries starting in 1994. However, foreign-born persons in the U.S. are a biased sample of the population of their countries of origin, and Global DRS data may not accurately predict their risk of drug resistance. Since implementing drug resistance surveillance in 1993, the U.S. National TB Surveillance System (NTSS) has accumulated systematic data on over 130,000 foreign-born TB cases from more than 200 countries and territories. Our objective was to determine whether the prevalence of drug resistance among foreign-born TB cases correlates better with data from the Global DRS or with data on foreign-born TB cases in the NTSS.Methods and FindingsWe compared the prevalence of resistance to isoniazid and rifampin among foreign-born TB cases in the U.S., 2007–2009, with US NTSS data from 1993 to 2006 and with Global DRS data from 1994–2007 visually with scatterplots and statistically with correlation and linear regression analyses. Among foreign-born TB cases in the U.S., 2007–2009, the prevalence of isoniazid resistance and multidrug resistance (MDR, i.e. resistance to isoniazid and rifampin), correlated much better with 1993–2006 US surveillance data (isoniazid: r = 0.95, P<.001, MDR: r = 0.75, P<.001) than with Global DRS data, 1994–2007 (isoniazid: r = 0.55, P = .001; MDR: r = 0.50, P<.001).ConclusionSince 1993, the US NTSS has accumulated sufficient data on foreign-born TB cases to estimate the risk of drug resistance among such individuals better than data from the Global DRS.

Estimating the Impact of Newly Arrived Foreign-Born Persons on Tuberculosis in the United States

BackgroundAmong approximately 163.5 million foreign-born persons admitted to the United States annually, only 500,000 immigrants and refugees are required to undergo overseas tuberculosis (TB) screening. It is unclear what extent of the unscreened nonimmigrant visitors contributes to the burden of foreign-born TB in the United States.Methodology/Principal FindingsWe defined foreign-born persons within 1 year after arrival in the United States as “newly arrived”, and utilized data from U.S. Department of Homeland Security, U.S. Centers for Disease Control and Prevention, and World Health Organization to estimate the incidence of TB among newly arrived foreign-born persons in the United States. During 2001 through 2008, 11,500 TB incident cases, including 291 multidrug-resistant TB incident cases, were estimated to occur among 20,989,738 person-years for the 1,479,542,654 newly arrived foreign-born persons in the United States. Of the 11,500 estimated TB incident cases, 41.6% (4,783) occurred among immigrants and refugees, 36.6% (4,211) among students/exchange visitors and temporary workers, 13.8% (1,589) among tourists and business travelers, and 7.3% (834) among Canadian and Mexican nonimmigrant visitors without an I-94 form (e.g., arrival-departure record). The top 3 newly arrived foreign-born populations with the largest estimated TB incident cases per 100,000 admissions were immigrants and refugees from high-incidence countries (e.g., 2008 WHO-estimated TB incidence rate of ≥100 cases/100,000 population/year; 235.8 cases/100,000 admissions, 95% confidence interval [CI], 228.3 to 243.3), students/exchange visitors and temporary workers from high-incidence countries (60.9 cases/100,000 admissions, 95% CI, 58.5 to 63.3), and immigrants and refugees from medium-incidence countries (e.g., 2008 WHO-estimated TB incidence rate of 15–99 cases/100,000 population/year; 55.2 cases/100,000 admissions, 95% CI, 51.6 to 58.8).Conclusions/SignificanceNewly arrived nonimmigrant visitors contribute substantially to the burden of foreign-born TB in the United States. To achieve the goals of TB elimination, direct investment in global TB control and strategies to target nonimmigrant visitors should be considered.

Immigrants and the Spread of Tuberculosis in the United States: A Hidden Cost of Immigration

This panel-data study concerns the incidence of newly diagnosed tuberculosis (TB) in specific U.S. metropolitan areas among immigrants and, in turn, the possible transmission of the disease to the native-born population of these same metropolitan areas. The study includes 50 U.S. Metropolitan Statistical Areas as annual observations, 1993–2007. We find that a 10% increase in the number of high-incidence immigrants results in a 2.87% increase in TB among the foreign-born population, and that a 10% increase in the number of foreign-born TB cases increases the number of new TB cases among the native-born by 1.11%. The study concludes with a benefit/cost analysis of the societal cost of TB and suggests that testing all immigrants for TB would be a cost-effective method to limit the amount of TB that enters U.S. from abroad, thus limiting the transmission to both the foreign- and native-born populations.

Clustering of Mycobacterium tuberculosis strains from foreign-born patients in Korea

Information on drug resistance and transmission patterns of tuberculosis (TB) in foreign-born patients is lacking in Asia where immigration is increasing. We examined the drug-resistance profiles of 288 Mycobacterium tuberculosis isolates from foreign-born patients in South Korea, and assessed for potential transmission in the host country by analysing their IS6110 genotypes, as well as those of 4780 strains from native Korean TB patients. The prevalence of multidrug-resistant (MDR) TB was 9.7% and 42% among new and previously treated patients, respectively. Chinese nationality was associated with MDR TB (OR(China)=3.0, 95% CI 1.1-9.3). Of the 288 strains, 51 (17.7%) formed 31 clusters, of which 22 were identical to strains from native Koreans. A number of strains belonged to the K family, subtypes known to occur endemically in Korea. MDR TB was common, and clustering patterns showed potential cross-cultural transmission among foreign-born TB patients. Further molecular epidemiological studies of all isolates in the area are needed to determine the extent of international TB transmission in Asia.

Piecing the puzzle together: foreign-born tuberculosis in an immigrant-receiving country

In major immigrant-receiving countries, annual foreign-born tuberculosis (TB) case counts and rates are relatively constant. Why this is so, and who might be a high-yield target for screening for latent TB infection, remain open questions. Foreign-born TB in Canada during 1986-2002 was retrospectively examined using national TB and immigration data as well as census data. Case counts and rates were analysed in relation to demographics, immigration period and time since arrival. Pre-1986 immigrants (n=3,860,853) and 1986-2002 immigrants (n=3,463,283) contributed 8,662 and 9,613 TB cases, respectively. Immigrants arriving ≤ 5 yrs ago and those arriving >10 yrs ago contributed almost equally to the annual foreign-born TB case count despite a 3.5-fold difference in in-country person-yrs. Remarkably stable and relatively low TB incidence was observed among immigrants >10 yrs post-arrival. Conversely, TB incidence within 5 yrs of arrival was dynamic, demonstrating a strong inverse association with time since arrival and higher sensitivity to changes in immigration level than shifts toward higher incidence source countries. Relative constancy in foreign-born TB incidence is explained by a complex convergence of several factors. Immigrants born in high-incidence countries who arrived ≤ 2 yrs ago and were aged 15-34 yrs upon arrival constitute high-yield targets for preventive therapy.

Tuberculosis among Foreign-born Persons, Singapore, 2000–2009

We determined the proportion of foreign-born persons with tuberculosis (TB) in Singapore. This proportion increased from 25.5% in 2004 to 37.6% in 2009. Unskilled workers from countries with high incidences of TB accounted for the highest number of and greatest increase in foreign-born TB case-patients.

Impact of immigration on tuberculosis in a low-incidence area of Italy: a molecular epidemiological approach

The effects that immigration might have on the epidemiology of tuberculosis (TB) in a low-incidence area of Italy was investigated by determining, in autochthonous and immigrant TB patients, the molecular characteristics of the Mycobacterium tuberculosis complex (MTBC) isolates, which may provide information on their phylogeographical origin. A total of 1080 MTBC strains, collected during a 4-year period in Tuscany from 614 Italian-born and 466 foreign-born patients, were genotyped by spoligotyping and assigned to the different phylogeographical lineages that constitute the MTBC. The autochthonous Euro-American phylogeographical lineage, which includes the spoligotype families T, Haarlem, Latin American–Mediterranean (LAM), S and X, was highly prevalent among Italian-born patients, with a total of 477 cases (77.7%), and foreign-born TB patients, with a total of 270 cases (57.9%); 24 Italian-born (3.9%) and 141 foreign-born (30.3%) TB cases were due to MTBC genotypic families associated with distant geographical areas, i.e. East African–Indian (EAI), Beijing, Central Asian (CAS), and Mycobacterium africanum. Strains of Mycobacterium bovis and strains of undefined genotype, which are all considered together, as it is not possible to assign a specific geographical origin, accounted for 113 (18.4%) Italian cases and 55 (11.8%) foreign-born cases. A total of 79 Italian TB cases (12.9%) have been attributed to transmission from immigrants to the local population. No significant contribution to drug resistance appeared to be associated with imported MTBC strains. It is concluded that, at present, the overall impact of imported TB on public health in the low-incidence study area is relatively modest and of the same order as in other western countries.

Tuberculosis transmission patterns among Spanish-born and foreign-born populations in the city of Barcelona

During a 2-year period (2003–2004), tuberculosis (TB) transmission in Barcelona and the factors related to transmission among the Spanish- and foreign-born populations were studied by molecular epidemiology. Data were obtained from TB cases and Conventional Contact Tracing registries and genotyping was performed using restriction fragment length polymorphism (RFLP)-IS6110 and MIRU12 as a secondary typing method. Of the 892 TB cases reported, 583 (65.3%) corresponded to Spanish-born and 309 (34.6%) to foreign-born. Six hundred and eighty-seven cases (77%) were confirmed by culture. RFLP typing of 463/687 (67.4%) isolates was performed, revealing 280 (60.5%) unique and 183 (39.5%) shared patterns, which were grouped into 65 clusters. Spanish-born individuals were significantly more clustered than foreign-born individuals (44.6% vs. 28.8%; p 0.016). Clustering in foreign-born individuals was associated with HIV (p 0.051, odds ratio = 3.1, 95% confidence interval 1–10.9) and alcohol abuse (p 0.022), whereas, in the Spanish-born individuals, clustering was associated with age in the range 21–50 years, (p 0.024). Of the total clusters, 36/65 (55.3%) included only Spanish-born patients, whereas 22/65 (33.8%) included individuals from both populations. In mixed clusters, the index case was Spanish-born in 53% and foreign-born in 47%. Among the foreign-born, 2.8% were ill on arrival, 30% developed TB within the first year and 50.3% developed TB within the first 2 years; 58.3% were from South America. In conclusion, half of the foreign-born TB patients developed the disease during the first 2 years after arrival, which, in most cases, was the result of endogenous reactivation. Recent TB transmission among Spanish-born and foreign-born populations, as well as bidirectional transmission between communities, contributed significantly to the burden of TB in Barcelona, suggesting the need to improve Public Health interventions in both populations.

Impact of immigration on tuberculosis in a low-incidence area of Italy: a molecular epidemiology approach

The effects that immigration might have on the epidemiology of tuberculosis (TB) in a low-incidence area of Italy was investigated by determining, in autochthonous and immigrant TB patients, the molecular characteristics of the Mycobacterium tuberculosis complex (MTBC) isolates, which may provide information on their phylogeographical origin. A total of 1080 MTBC strains, collected during a 4- year period in Tuscany from 614 Italian-born and 466 foreign-born patients, were genotyped by spoligotyping and assigned to the different phylogeographical lineages that constitute the MTBC. The autochthonous Euro-American phylogeographical lineage, which includes the spoligotype families T, Haarlem, Latin American–Mediterranean (LAM), S and X, was highly prevalent among Italian-born patients, with a total of 477 cases (77.7%), and foreign-born TB patients, with a total of 270 cases (57.9%); 24 Italian-born (3.9%) and 141 foreign- born (30.3%) TB cases were due to MTBC genotypic families associated with distant geographical areas, i.e. East African–Indian (EAI), Beijing, Central Asian (CAS), and Mycobacterium africanum. Strains of Mycobacterium bovis and strains of undefined genotype, which are all considered together, as it is not possible to assign a specific geographical origin, accounted for 113 (18.4%) Italian cases and 55 (11.8%) foreign-born cases. A total of 79 Italian TB cases (12.9%) have been attributed to transmission from immigrants to the local population. No significant contribution to drug resistance appeared to be associated with imported MTBC strains. It is concluded that, at present, the overall impact of imported TB on public health in the low-incidence study area is relatively modest and of the same order as in other western countries.

Tuberculosis in South Asians Living in the United States, 1993-2004

Patients with tuberculosis (TB) in the United States are often described in 2 broad categories, US-born and foreign-born, which may mask differences among different immigrant groups. We determined characteristics of patients born in South Asia and diagnosed as having TB in the United States. All 224,101 TB cases reported to the US National Tuberculosis Surveillance System from the 50 states and the District of Columbia from 1993 to 2004 were included. We used descriptive analysis and logistic regression to explore differences among patients born in South Asia, other foreign-born, and US-born TB patients. Half of the South Asian TB patients (50.5%) in our study were in the 25- to 44-year-old age group, compared with 40.1% of other foreign-born TB patients and 31.8% of US-born TB patients. Compared with other foreign-born TB patients, South Asians were more likely to have extrapulmonary disease (odds ratio [OR], 1.7), more likely to be uninfected with human immunodeficiency virus (HIV) (OR, 5.8) but also more likely not to be offered HIV testing (OR, 9.4) or not to accept an HIV test if offered (OR, 11.8), and more likely not to be homeless (OR, 2.9) or not to use drugs or excess alcohol (OR, 2.7). South Asian TB patients in the United States are younger and more commonly develop extrapulmonary TB than other foreign-born patients. New TB control strategies that target younger patients and that encourage HIV testing and inform physicians about high extrapulmonary TB in the absence of common risk factors in South Asians are needed.

Tuberculosis Among Foreign-born Persons in Taiwan, 2002–2005

The foreign-born population has been growing in Taiwan. Most foreign-born persons come from countries with a high burden of tuberculosis (TB). Monitoring the trend and characteristics of TB in this population is essential for TB control in Taiwan. Information about foreign-born persons residing in Taiwan and data of all foreign-born TB cases notified during 2002-2005 were obtained from the national authorities and analyzed. A total of 2,444 foreign-born TB cases were notified during 2002-2005, which accounted for 3.6% of all notified TB cases during that period in Taiwan. The proportion of foreign-born TB cases was constant, without any significant yearly variation. The average annual TB notification rate in the foreign-born population was higher than that in the Taiwan-born population (94.0/100,000 vs. 72.0/100,000). There were significant differences in age, sex and regional distribution between foreign-born and Taiwan-born TB cases (p < 0.001). Foreign-born cases were predominantly female (65.4%) and aged 25-44 years (70.9%), whereas the majority of cases among the Taiwan-born population were male (69.4%) and aged > or = 65 years (49.6%). Most foreign-born TB patients (62.7%) lived in northern Taiwan but only about one-third (36.1%) of Taiwan-born TB cases were notified from that region. Among foreign-born TB cases whose original countries were recorded, the majority came from Mainland China and Vietnam, which accounted for 73.0% of all cases, followed by the Philippines (7.4%), Thailand (7.3%) and Indonesia (6.0%). Foreign-born TB patients have different profiles and a higher case rate compared to Taiwan-born patients. Monitoring the epidemiologic trend of TB among foreign-born persons, especially those who come from high TB-burden countries, is essential in the fight against TB in Taiwan.

Evaluation and Epidemiological Research in Tuberculosis Control: Linking Medical Care and Public Health

Evaluation and Epidemiological Research in Tuberculosis Control: Linking Medical Care and Public Health

Diversity of Mycobacterium tuberculosis isolates in an immigrant population: evidence against a founder effect.

Population-based studies have used DNA typing of Mycobacterium tuberculosis organisms to estimate the extent of ongoing tuberculosis transmission in various communities and to characterize associated risk factors. The finding of matched DNA "fingerprints" among isolates from an immigrant subgroup may reflect transmission in the adopted country but could also reflect limited diversity among M. tuberculosis organisms within that immigrant community. The authors sought to determine which hypothesis is more likely to explain the high frequency of matched isolates among Haitian-born tuberculosis patients in Montreal, Quebec, Canada. The authors determined the number of different bacterial genotypes in this community as compared with other foreign-born tuberculosis patients and applied a recently described measure of genetic similarity between M. tuberculosis organisms ("genetic distance"). Among 76 Haitian-born tuberculosis patients diagnosed during 1996-1998, the authors identified 47 distinct genotypes on the basis of standard IS6110 DNA typing and categorical analysis. In genetic distance analysis, these 47 genotypes showed as great a genetic diversity as that observed among the 191 distinct genotypes identified in 216 other foreign-born tuberculosis patients. A mycobacterial "founder effect" is unlikely to account for the high proportion of shared isolates among Haitian-born Montrealers. Recent transmission remains the most likely explanation.

Epidemiologic differences between United States- and foreign-born tuberculosis patients in Houston, Texas.

The proportion of foreign-born tuberculosis patients in the United States is increasing. To analyze the epidemiology of tuberculosis in foreign-born people, culture-positive patients with tuberculosis in Houston, Texas, were interviewed from October 1995 through September 1998, and their isolates were molecularly characterized. Of the 1131 patients included in the study, 795 (70.3%) were US born and 336 (29.7%) were foreign born. The decrease in tuberculosis case rate among US-born people was 3.5 times that of foreign-born people. Significantly more US-born than foreign-born patients belonged to strain clusters (71.3% vs. 29.5%; P<.001). Risk factors associated with strain clustering were as follows: black ethnicity, low income, and homelessness in US-born patients and homelessness in foreign-born patients. Isolates from foreign-born patients were more likely to be resistant to >/=1 drug (15.4% vs. 8.4%; P=.001) and to be multidrug resistant (2.4% vs. 0.7%; P=.027) than isolates from US-born patients. These observations warrant increased emphasis on this distinct subpopulation of tuberculosis patients.