Long-term risk of tuberculosis among foreign-born persons in the United States

Comparison of the yield of two tuberculosis screening approaches among household contacts in a community setting of Silti Zone, Central Ethiopia: a prospective cohort study

BACKGROUND

Household contacts of tuberculosis (TB) patients are at a greater risk of infection and developing TB as well. Despite recommendations to actively screen such high-risk groups for TB, it is poorly implemented in Ethiopia. A community-based household contact screening was conducted to compare the yield of two different screening approaches and to identify factors associated with TB occurrence.

METHODS

Smear-positive pulmonary TB index cases from six health facilities in six districts of Silti Zone were identified and enrolled prospectively between September 2020 and December 2022. Trained healthcare workers conducted house visits to screen household contacts for TB. WHO (World Health Organization) recommended symptom-based screening algorithms were used. The yield of screening was compared between a two-time screening at study site I and a single baseline screening at study site II, which is the current programmatic approach. Generalized estimating equation was used to run multivariate logistic regression to identify factors associated with TB occurrence.

RESULTS

A total of 387 index TB cases (193 at site I and 194 at site II) with 1,276 eligible contacts were included for analysis. The TB yield of repeat screening approach did not show a significant difference compared to a single screening (2.3% at site I vs. 1.1% at site II, p < 0.072). The number needed to screen was 44 and 87 for the repeat and single screening, respectively, indicating a high TB burden in both settings. The screening algorithm for patients with comorbidities of asthma and heart failure had a 100% sensitivity, 19.1% specificity and a positive predictive value of 5.6%. Cough [AOR: 10.9, 95%CI: 2.55,46.37], fatigue [AOR: 6.1, 95%CI: 1.76,21.29], daily duration of contact with index case [AOR: 4.6, 95%CI; 1.57,13.43] and age of index cases [AOR: 0.9, 95%CI; 0.91-0.99] were associated with the occurrence of TB among household contacts.

CONCLUSION

Our study showed that the yield of TB was not significantly different between one-time screening and repeat screening. Although repeat screening has made an addition to case notification, it should be practiced only if resources permit. Cough, fatigue, duration of contact and age of index cases were factors associated with TB. Further studies are needed to establish the association between older age and the risk of transmitting TB.

Risk Factors for Tuberculosis and Effect of Preventive Therapy Among Close Contacts of Persons With Infectious Tuberculosis

BACKGROUND

Close contacts of persons with pulmonary tuberculosis (TB) have high rates of TB disease.

METHODS

We prospectively enrolled TB patients and their close contacts at 9 US/Canadian sites. TB patients and contacts were interviewed to identify index patient, contact, and exposure risk factors for TB. Contacts were evaluated for latent TB infection (LTBI) and TB, and the effectiveness of LTBI treatment for preventing contact TB was examined.

RESULTS

Among 4490 close contacts, multivariable risk factors for TB were age ≤5 years, US/Canadian birth, human immunodeficiency virus infection, skin test induration ≥10 mm, shared bedroom with an index patient, exposure to more than 1 index patient, and index patient weight loss (P < .05 for each). Of 1406 skin test-positive contacts, TB developed in 49 (9.8%) of 446 who did not initiate treatment, 8 (1.8%) of 443 who received partial treatment, and 1 (0.2%) of 517 who completed treatment (1951, 290, and 31 cases/100 000 person-years, respectively; P < .001). TB was diagnosed in 4.2% of US/Canadian-born compared with 2.3% of foreign-born contacts (P = .002), and TB rates for US/Canadian-born and foreign-born contacts who did not initiate treatment were 3592 and 811 per 100 000 person-years, respectively (P < .001).

CONCLUSIONS

Treatment for LTBI was highly effective in preventing TB among close contacts of infectious TB patients. Several index patient, contact, and exposure characteristics associated with increased risk of contact TB were identified. These findings help inform contact investigation, LTBI treatment, and other public health prevention efforts.

Diagnostic pathways and delay among tuberculosis patients in Stockholm, Sweden: a retrospective observational study

BACKGROUND

Asylum seekers in Sweden are offered tuberculosis (TB) screening at a voluntary post-arrival health examination. The role of this screening in improving the TB diagnostic pathway has not been previously evaluated. The aim of this study was to determine diagnostic pathways for active TB cases and compare diagnostic delays between different pathways.

METHODS

Retrospective review of medical records of patients reported with active TB in Stockholm in 2015, using a structured and pre-coded form.

RESULTS

Seventy-one percent of patients actively sought health care due to symptoms. As for source of referral to TB specialist clinic, 15% came from screening of eligible migrants, of whom the majority were asymptomatic. Among asylum seekers, 69% were identified through screening at a health examination (HE). The main sources of referral to TB clinics were emergency departments (27%) and primary health care centers (20%). Median health care provider delay was significantly longer in patients identified through migrant screening in health examination.

CONCLUSIONS

Screening at a health examination was the main pathway of active TB detection among mainly asymptomatic and non-contagious asylum seekers but contributed modestly to total overall TB case detection. In these patients TB was diagnosed early in a non-contagious phase of the disease. Further research is required to assess the effectiveness and cost-effectiveness of HE TB screening as well as inclusion of other groups of migrants from high incidence countries in the screening program in terms of impact on delay, transmission and treatment outcomes.

Risk and Timing of Tuberculosis Among Close Contacts of Persons with Infectious Tuberculosis

Background

The risk and timing of tuberculosis among recently exposed close contacts of patients with infectious tuberculosis are not well established.

Methods

We prospectively enrolled patients ≥15 years of age with culture-confirmed pulmonary tuberculosis and their close contacts at 9 health departments in the United States and Canada. Close contacts were screened and cross-matched with tuberculosis registries to identify those who developed tuberculosis.

Results

Tuberculosis was diagnosed in 158 of 4490 contacts (4%) of 718 index patients with tuberculosis. Of tuberculosis cases among contacts, cumulative totals of 81 (51%), 119 (75%), 128 (81%), and 145 (92%) were diagnosed by 1, 3, 6, and 12 months, respectively, after the index patients' diagnosis. Tuberculosis rates among contacts were 2644, 115, 46, 69, and 25 cases per 100000 persons, respectively, in the 5 consecutive years after the index patients' diagnosis. Of the tuberculosis cases among contacts, 121 (77%) were identified by contact investigation and 37 (23%) by tuberculosis registry cross-match.

Conclusions

Close contacts to infectious patients with tuberculosis had high rates of tuberculosis, with most disease diagnosed before or within 3 months after the index patient' diagnosis. Contact investigations need to be prompt to detect tuberculosis and maximize the opportunity to identify and treat latent infection, to prevent disease.

Factors influencing the higher incidence of tuberculosis among migrants and ethnic minorities in the UK

Migrants and ethnic minorities in the UK have higher rates of tuberculosis (TB) compared with the general population. Historically, much of the disparity in incidence between UK-born and migrant populations has been attributed to differential pathogen exposure, due to migration from high-incidence regions and the transnational connections maintained with TB endemic countries of birth or ethnic origin. However, focusing solely on exposure fails to address the relatively high rates of progression to active disease observed in some populations of latently infected individuals. A range of factors that disproportionately affect migrants and ethnic minorities, including genetic susceptibility, vitamin D deficiency and co-morbidities such as diabetes mellitus and HIV, also increase vulnerability to infection with Mycobacterium tuberculosis (M.tb) or reactivation of latent infection. Furthermore, ethnic socio-economic disparities and the experience of migration itself may contribute to differences in TB incidence, as well as cultural and structural barriers to accessing healthcare. In this review, we discuss both biological and anthropological influences relating to risk of pathogen exposure, vulnerability to infection or development of active disease, and access to treatment for migrant and ethnic minorities in the UK.

Factors influencing the higher incidence of tuberculosis among migrants and ethnic minorities in the UK

Migrants and ethnic minorities in the UK have higher rates of tuberculosis (TB) compared with the general population. Historically, much of the disparity in incidence between UK-born and migrant populations has been attributed to differential pathogen exposure, due to migration from high-incidence regions and the transnational connections maintained with TB endemic countries of birth or ethnic origin. However, focusing solely on exposure fails to address the relatively high rates of progression to active disease observed in some populations of latently infected individuals. A range of factors that disproportionately affect migrants and ethnic minorities, including genetic susceptibility, vitamin D deficiency and co-morbidities such as diabetes mellitus and HIV, also increase vulnerability to infection with Mycobacterium tuberculosis (M.tb) or reactivation of latent infection. Furthermore, ethnic socio-economic disparities and the experience of migration itself may contribute to differences in TB incidence, as well as cultural and structural barriers to accessing healthcare. In this review, we discuss both biological and anthropological influences relating to risk of pathogen exposure, vulnerability to infection or development of active disease, and access to treatment for migrant and ethnic minorities in the UK.

Investigations on the Influence of Zidovudine in the Pharmacokinetics of Isoniazid and Its Hepatotoxic Metabolites in Rats

The HIV-infected patients are co-infected with many bacterial infections in which tuberculosis is most common found worldwide. These patients are often administered with combined therapy of anti-retroviral and anti-tubercular drugs which leads to several complications including hepatotoxicity or adverse drug interactions. The drug-drug interactions between the anti-retroviral and anti-tubercular drugs are not clearly defined and hence, this study was conducted to evaluate the pharmacokinetic drug-drug interactions of Zidovudine (AZT) with Isoniazid (INH) and its hepatotoxic metabolites. Seventy two rats were randomly divided into two major groups with their sub-groups each comprising 6 animals. The Group I received INH alone at a dose of 25 mg/kg; b.w and Group II received AZT (50 mg/kg; b.w) along with INH orally. Pharmacokinetic studies of INH and its metabolites i.e., acetyl hydrazine (ACHY) and hydrazine (HYD) shows that INH and ACHY attains maximum plasma concentration ( C_max) within 30 minutes and HYD attains C_max at 1 hour after INH administration and all these analytes disappear from plasma within 4 hours. Pharmacokinetic studies also revealed that AZT treatment did not showed any drug-drug interactions and have no effect on the T_1/2, plasma clearance, AUC, C_max and T_max of INH and its hepatotoxic metabolites.

Mexican Immigrants’ Explanatory Model of Latent Tuberculosis Infection

This article reveals how the multiple and disparate explanations of latent tuberculosis infection (LTBI) from the U.S. and Mexico professional health sectors and the popular sector are used to inform the explanatory model (EM) of LTBI for Mexican immigrants residing in the U.S.-Mexico border region. Fourteen immigrants, nine diagnosed with LTBI (n = 9) and their spouses (n = 5) participated in this critical ethnographic study. Because care seeking and treatment decisions are influenced by EMs, the results indicate that it is imperative that interventions for Mexican immigrants with LTBI are built on an understanding of their illness experience and are contextually meaningful.

Abrupt Decline in Tuberculosis among Foreign-Born Persons in the United States

While the number of reported tuberculosis (TB) cases in the United States has declined over the past two decades, TB morbidity among foreign-born persons has remained persistently elevated. A recent unexpected decline in reported TB cases among foreign-born persons beginning in 2007 provided an opportunity to examine contributing factors and inform future TB control strategies. We investigated the relative influence of three factors on the decline: 1) changes in the size of the foreign-born population through immigration and emigration, 2) changes in distribution of country of origin among foreign-born persons, and 3) changes in the TB case rates among foreign-born subpopulations. Using data from the U.S. National Tuberculosis Surveillance System and the American Community Survey, we examined TB case counts, TB case rates, and population estimates, stratified by years since U.S. entry and country of origin. Regression modeling was used to assess statistically significant changes in trend. Among foreign-born recent entrants (<3 years since U.S. entry), we found a 39.5% decline (-1,013 cases) beginning in 2007 (P<0.05 compared to 2000–2007) and ending in 2011 (P<0.05 compared to 2011–2014). Among recent entrants from Mexico, 80.7% of the decline was attributable to a decrease in population, while the declines among recent entrants from the Philippines, India, Vietnam, and China were almost exclusively (95.5%–100%) the result of decreases in TB case rates. Among foreign-born non-recent entrants (≥3 years since U.S. entry), we found an 8.9% decline (-443 cases) that resulted entirely (100%) from a decrease in the TB case rate. Both recent and non-recent entrants contributed to the decline in TB cases; factors contributing to the decline among recent entrants varied by country of origin. Strategies that impact both recent and non-recent entrants (e.g., investment in overseas TB control) as well as those that focus on non-recent entrants (e.g., expanded targeted testing of high-risk subgroups among non-recent entrants) will be necessary to achieve further declines in TB morbidity among foreign-born persons.

Transnational Record Linkage for Tuberculosis Surveillance and Program Evaluation

OBJECTIVE

Pre-immigration tuberculosis (TB) screening, followed by post-arrival rescreening during the first year, is critical to reducing TB among foreign-born people in the United States. However, existing U.S. public health surveillance is inadequate to monitor TB among immigrants during subsequent years. We developed and tested a novel method for ascertaining post-U.S.-arrival TB outcomes among high-TB-risk immigrant cohorts to improve surveillance.

METHODS

We used a probabilistic record linkage program to link pre-immigration screening records from U.S.-bound immigrants from the Philippines (n=422,593) and Vietnam (n=214,401) with the California TB registry during 2000-2010. We estimated sensitivity using Monte Carlo simulations to account for uncertainty in key inputs. Specificity was evaluated by using a time-stratified approach, which defined false-positives as TB records linked to pre-immigration screening records dated after the person had arrived in the United States.

RESULTS

TB was reported in 4,382 and 2,830 people born in the Philippines and Vietnam, respectively, in California during the study period. Of these TB cases, records for 973 and 452 cases of people born in the Philippines and Vietnam, respectively, were linked to pre-immigration screening records. Sensitivity and specificity of linkage were 89% (90% credible interval [CrI] 83, 97) and 100%, respectively, for the Philippines, and 90% (90% CrI 83, 98) and 99.9%, respectively, for Vietnam.

CONCLUSION

Electronic linkage of pre-immigration screening records to a domestic TB registry was feasible, sensitive, and highly specific in two high-priority immigrant cohorts. Transnational record linkage can be used for program evaluation and routine monitoring of post-U.S.-arrival TB risk among immigrants, but requires interagency data sharing and collaboration.

Knowledge and Perceptions of Latent Tuberculosis Infection among Chinese Immigrants in a Canadian Urban Centre

Background. Since most tuberculosis (TB) cases in immigrants to British Columbia (BC), Canada, develop from latent TB infection (LTBI), treating immigrants for LTBI can contribute to the eradication of TB. However, adherence to LTBI treatment is a challenge that is influenced by knowledge and perceptions. This research explores Chinese immigrants' knowledge and perceptions towards LTBI in Greater Vancouver. Methods. This mixed methods study included a cross-sectional patient survey at BC's Provincial TB clinics and two focus group discussions (FGDs) with Chinese immigrants. Data from FGDs were coded and analyzed in Simplified Chinese. Codes, themes, and selected quotes were then translated into English. Results. The survey identified a mean basic knowledge score: 40.0% (95% CI: 38.3%, 41.7%). FGDs confirmed that Chinese immigrants' knowledge of LTBI was low, and they confused it with TB disease to the extent of experiencing LTBI associated stigma. Participants also expressed difficulties navigating the health system which impeded testing and treatment of LTBI. Online videos were the preferred format for receiving health information. Conclusion. We identified striking gaps in knowledge surrounding an LTBI diagnosis. Concerns of stigma may influence acceptance and adherence of LTBI treatment in Chinese immigrants. Integrating these findings into routine health care is recommended.

Estimated Prevalence of Tuberculosis Infection Among a New York City Clinic Population Using Interferon-gamma Release Assays

Using QuantiFERON®-Gold In-Tube (QFT-GIT) data, the prevalence of tuberculosis infection in New York City was estimated. Patient characteristics associated with a positive result were consistent with known tuberculosis risk factors. Results suggest that blood-based tests for tuberculosis infection are reliable.

Background

 Elimination of tuberculosis (TB) in the United States requires treating not only persons with active disease but also those infected with TB. Achieving this goal requires understanding local TB infection prevalence and identifying subgroups at increased risk for infection and disease.

Methods

 The study population included all patients tested with an interferon-gamma release assay (IGRA) test at New York City (NYC) public TB clinics from October 1, 2006 to December 31, 2011. Patients who were not a case or contact at testing (general clinic patients) and who had a positive QuantiFERON-Gold In-Tube (QFT-GIT) test result were compared with those with indeterminate or negative results to identify characteristics associated with positive results. New York City TB surveillance data were used to identify clinic patients later diagnosed with active TB disease.

Results

 A total of 69 273 IGRA tests were conducted. Among 20 066 patients tested with QFT-GIT, 16% tested positive, 83% tested negative, and <1% were indeterminate. Of 18 481 general clinic patients, 14% had a positive QFT-GIT result. Nine percent of United States-born patients compared with 19% of foreign-born patients had a positive result. Increasing age and birth in a high-incidence country were associated with a higher likelihood of having a positive result. One patient with a negative QFT-GIT result was identified as a TB case 2 years later.

Conclusions

 Using QFT-GIT data, the background prevalence of TB infection in NYC was estimated. Patient characteristics associated with a positive QFT-GIT result were consistent with known TB risk factors. Results suggest that IGRAs are reliable tests for TB infection.

Selecting suitable solid organ transplant donors: Reducing the risk of donor-transmitted infections

Selection of the appropriate donor is essential to a successful allograft recipient outcome for solid organ transplantation. Multiple infectious diseases have been transmitted from the donor to the recipient via transplantation. Donor-transmitted infections cause increased morbidity and mortality to the recipient. In recent years, a series of high-profile transmissions of infections have occurred in organ recipients prompting increased attention on the process of improving the selection of an appropriate donor that balances the shortage of needed allografts with an approach that mitigates the risk of donor-transmitted infection to the recipient. Important advances focused on improving donor screening diagnostics, using previously excluded high-risk donors, and individualizing the selection of allografts to recipients based on their prior infection history are serving to increase the donor pool and improve outcomes after transplant. This article serves to review the relevant literature surrounding this topic and to provide a suggested approach to the selection of an appropriate solid organ transplant donor.

Decline in tuberculosis among Mexico-born persons in the United States, 2000-2010

BACKGROUND

In 2010, Mexico was the most common (22.9%) country of origin for foreign-born persons with tuberculosis in the United States, and overall trends in tuberculosis morbidity are substantially influenced by the Mexico-born population.

OBJECTIVES

To determine the risk of tuberculosis disease among Mexico-born persons living in the United States.

METHODS

Using data from the U.S. National Tuberculosis Surveillance System and the American Community Survey, we examined tuberculosis case counts and case rates stratified by years since entry into the United States and geographic proximity to the United States-Mexico border. We calculated trends in case rates over time measured by average annual percent change.

RESULTS

The total tuberculosis case count (-14.5%) and annual tuberculosis case rate (average annual percent change -5.1%) declined among Mexico-born persons. Among those diagnosed with tuberculosis less than 1 year since entry into the United States (newly arrived persons), there was a decrease in tuberculosis cases (-60.4%), no change in tuberculosis case rate (average annual percent change of 0.0%), and a decrease in population (-60.7%). Among those living in the United States for more than 5 years (non-recently arrived persons), there was an increase in tuberculosis cases (+3.4%), a decrease in tuberculosis case rate (average annual percent change of -4.9%), and an increase in population (+62.7%). In 2010, 66.7% of Mexico-born cases were among non-recently arrived persons, compared with 51.1% in 2000. Although border states reported the highest proportions (>15%) of tuberculosis cases that were Mexico-born, the highest Mexico-born-specific tuberculosis case rates (>20/100,000 population) were in states in the eastern and southeastern regions of the United States.

CONCLUSIONS

The decline in tuberculosis morbidity among Mexico-born persons may be attributed to fewer newly arrived persons from Mexico and lower tuberculosis case rates among non-recently arrived Mexico-born persons. The extent of the decline was dampened by an unchanged tuberculosis case rate among newly arrived persons from Mexico and a large increase in the non-recently arrived Mexico-born population. If current trends continue, tuberculosis morbidity among Mexico-born persons will be increasingly driven by those who have been living in the United States for more than 5 years.

Persistent latent tuberculosis reactivation risk in United States immigrants

RATIONALE

Current guidelines limit latent tuberculosis infection (LTBI) evaluation to persons in the United States less than or equal to 5 years based on the assumption that high TB rates among recent entrants are attributable to high LTBI reactivation risk, which declines over time. We hypothesized that high postarrival TB rates may instead be caused by imported active TB.

OBJECTIVES

Estimate reactivation and imported TB in an immigrant cohort.

METHODS

We linked preimmigration records from a cohort of California-bound Filipino immigrants during 2001-2010 with subsequent TB reports. TB was likely LTBI reactivation if the immigrant had no evidence of active TB at preimmigration examination, likely imported if preimmigration radiograph was abnormal and TB was reported less than or equal to 6 months after arrival, and likely reactivation of inactive TB if radiograph was abnormal but TB was reported more than 6 months after arrival.

MEASUREMENTS AND MAIN RESULTS

Among 123,114 immigrants, 793 TB cases were reported. Within 1 year of preimmigration examination, 85% of TB was imported; 6 and 9% were reactivation of LTBI and inactive TB, respectively. Conversely, during Years 2-9 after U.S. entry, 76 and 24% were reactivation of LTBI and inactive TB, respectively. The rate of LTBI reactivation (32 per 100,000) did not decline during Years 1-9.

CONCLUSIONS

High postarrival TB rates were caused by detection of imported TB through active postarrival surveillance. Among immigrants without active TB at baseline, reported TB did not decline over 9 years, indicating sustained high risk of LTBI reactivation. Revised guidelines should support LTBI screening and treatment more than 5 years after U.S. arrival.

Tuberculosis in pregnancy: current recommendations for screening and treatment in the USA

The main focus of this review is the management of active and latent tuberculosis in pregnancy in industrialized countries. The review is geared towards the healthcare professional taking care of the obstetric patient. The epidemiology of active and latent tuberculosis in the USA and recommendations for the screening of tuberculosis in pregnancy are considered. The history of treatment methodology and its relationship to the current treatment of active and latent tuberculosis in pregnancy is reviewed, and finally, a discussion of the best time to treat latent tuberculosis in a pregnant patient is undertaken, along with thoughts on future changes and advances in this field.

Tuberculosis in indigenous communities of Antioquia, Colombia: epidemiology and beliefs

Morbidity and mortality caused by tuberculosis are increased in most of the Latin-American indigenous communities. Factors that could explain this situation are poverty and limited health services access due to social conflicts and geographical isolation. We determined the frequency of tuberculosis in Colombian indigenous communities and described their knowledge related to transmission and control. We developed a descriptive study and health survey. Interviews were performed to find ancestral knowledge about tuberculosis. Sputum samples from patients with respiratory symptoms were analyzed. 10 indigenous communities were studied, which tuberculosis incidence was 291/100,000. Communities believe that tuberculosis is a body and spirit disease, which transmission is by direct contact or by witchcraft. Tuberculosis incidence in the studied communities was ninefold higher than that of the general population from Antioquia Department. Knowledge exchange could facilitate the community empowerment and implementation of educational activities which might improve the control of the disease.

Tuberculosis in migrant populations. A systematic review of the qualitative literature

BACKGROUND

The re-emergence of tuberculosis (TB) in low-incidence countries and its disproportionate burden on immigrants is a public health concern posing specific social and ethical challenges. This review explores perceptions, knowledge, attitudes and treatment adherence behaviour relating to TB and their social implications as reported in the qualitative literature.

METHODS

Systematic review in four electronic databases. Findings from thirty selected studies extracted, tabulated, compared and synthesized.

FINDINGS

TB was attributed to many non-exclusive causes including air-born transmission of bacteria, genetics, malnutrition, excessive work, irresponsible lifestyles, casual contact with infected persons or objects; and exposure to low temperatures, dirt, stress and witchcraft. Perceived as curable but potentially lethal and highly contagious, there was confusion around a condition surrounded by fears. A range of economic, legislative, cultural, social and health system barriers could delay treatment seeking. Fears of deportation and having contacts traced could prevent individuals from seeking medical assistance. Once on treatment, family support and "the personal touch" of health providers emerged as key factors facilitating adherence. The concept of latent infection was difficult to comprehend and while TB screening was often seen as a socially responsible act, it could be perceived as discriminatory. Immigration and the infectiousness of TB mutually reinforced each another exacerbating stigma. This was further aggravated by indirect costs such as losing a job, being evicted by a landlord or not being able to attend school.

CONCLUSIONS

Understanding immigrants' views of TB and the obstacles that they face when accessing the health system and adhering to a treatment programme-taking into consideration their previous experiences at countries of origin as well as the social, economic and legislative context in which they live at host countries- has an important role and should be considered in the design, evaluation and adaptation of programmes.

The history and evolution of immigration medical screening for tuberculosis

Identifying and managing TB in immigrating populations has been an important aspect of immigration health for over a century, with the primary aim being protecting the host population by preventing the import of communicable diseases carried by the arriving migrants. This review describes the history and development of screening for TB and latent TB infection in the immigration context (describing both screening strategies and diagnostic tests used over the last century), outlining current practices and considering the future impact of new advances in screening. The recent focus of the WHO, regarding their elimination strategy, is further increasing the importance of diagnosing and treating latent TB infection. The last section of this review discusses the latest public health developments in the context of TB screening in immigrant populations.

Tuberculosis among Africans living in the United States, 2000-2009

The incidence of tuberculosis (TB) has declined steadily in the United States; however, foreign-born persons are disproportionately affected. The aim of our study was to describe characteristics of TB patients diagnosed in the United States who originated from the African continent. Using data from the U.S. National Tuberculosis Surveillance System, we calculated TB case rates and analyzed differences between foreign-born patients from Africa compared with other foreign-born and U.S.-born patients. The 2009 TB case rate among Africans (48.1/100,000) was 3 times as high as among other foreign-born and 27 times as high as among U.S.-born patients. Africans living in the United States have high rates of TB disease; they are more likely to be HIV-positive and to have extrapulmonary TB. Identification and treatment of latent TB infection, HIV testing and treatment, and a high index of suspicion for extrapulmonary TB are needed to better address TB in this population.

Infectious disease burden and vaccination needs among asylees versus refugees, district of columbia

BACKGROUND

Unlike US-bound refugees, asylum seekers (asylees) apply for asylum while residing in the United States and are not provided a medical screening. Infectious disease burden and vaccination needs have not been described among US asylees.

METHODS

We conducted a retrospective cohort study of 630 asylees and 151 refugees referred to the District of Columbia (DC) Department of Health screening program for an initial US medical screening during September 2003-August 2007. We assessed the prevalence of latent tuberculosis infection (tuberculin skin test reactivity ≥10 mm), human immunodeficiency virus (HIV) and hepatitis B seropositivity, intestinal parasite test positivity, need for vaccinations, and time from date of US arrival to receipt of screening.

RESULTS

Asylees in DC had a similar prevalence as refugees of latent tuberculosis infection (39% vs 38%, respectively, P = .83), pathogenic intestinal parasites (4% vs 2%, P = .36), and need for adult vaccinations (80% vs 80%, P = .95). Asylees were screened significantly later after US arrival compared with refugees (55 weeks vs 1 week, P < .001). Asylees had higher prevalence of latent tuberculosis infection, hepatitis B and HIV seropositivity, and child and adult vaccination needs than the US population (P < .001).

CONCLUSIONS

This study of the infectious disease concerns of a US asylee population suggests that in DC, asylees have similar infectious disease burden and prevention needs as refugees and should be screened with the same urgency. Because applicants for US asylum are not linked to prompt medical screenings, DC asylees are typically screened much later, placing them and US communities at risk.

[Comparative epidemiological study of the tuberculosis - migrant and native subjects in Guadeloupe from 2006 to 2011]

INTRODUCTION

Most of the migrants residing in Guadeloupe are from neighboring Caribbean islands, some of which are characterized by a high incidence of tuberculosis. The objective of this retrospective and observational study was to define the epidemiological characteristics of tuberculosis affecting migrant and native populations in Guadeloupe.

METHODS

We describe all cases of tuberculosis in Guadeloupe identified in these two populations between 1 July 2006 and 30 June 2011.

RESULTS

The incidence of TB among migrants in Guadeloupe was seven times higher than that in native subjects in 2010 (33.4 vs. 5.5 new cases/100,000 inhabitants). Tuberculosis affecting the migrant population was characterized by young age of the patients (42 vs. 55 years) and a significant proportion of co-infection by the human immunodeficiency virus (HIV) (47 vs. 14%, P<0.001). Among the patient population studied, the HIV infection increased the risk of developing severe tuberculosis (adjusted odds ratio: 2.9; 95%CI: 1.2-6.8). Moreover, HIV infection was also a risk factor for death where the infection was not controlled (CD4 count <200 units per microliter; adj risk ratio: 3.9; 1.2-12.4).

CONCLUSION

This study shows that the migrant population in Guadeloupe is at increased risk of tuberculosis and should be considered as a priority target for tuberculosis control program.

Health care practices of the foreign born Asian Indians in the United States. A community based survey

Although successful utilization of medical and preventive care by members of the non-US born communities is an important public health concern, our knowledge regarding health practices of different ethnic subgroups is limited. In the present study, participants of the health fairs organized during South Asian cultural and religions events were asked anonymously to complete the South Asian Total Health Initiative (SATHI) health survey questionnaire to evaluate their health-related practices, self-health perception, and satisfaction with medical care. Among 1,250 surveyed, 1,016 foreign born Asian Indians adults that represented the fastest growing subgroups of the South Asian born nationals in the US were included in the analysis. We found that the majority reported healthy behavior (exercise activities and abstinence from alcohol or tobacco), high self-health perception, satisfaction with medical care, and compliance with annual routine medical examinations that was directly associated with the annual house income. Approximately 40% of women complied with breast and cervical cancer screenings and less than 20% of men complied with prostate cancer screening guidelines. Presence of chronic conditions (mostly cardiovascular pathology and/or diabetes) that were reported by approximately half of the participants negatively impacted their self-health perception. In conclusion, positive self-reported health perception and compliance with routine health examinations of the surveyed foreign born Asian Indians was reported along with an increased rate of chronic morbidity and underutilization of specific preventive services. Observed discrepancy between self-health perception and health status highlights the need to enhance utilization of preventive services among the non-US born Asian Indian community.

Tuberculosis in special populations

The susceptibility to infection, the pathogenesis and the clinical manifestations of tuberculosis (TB) depend on the immunological status of the host. Immunological status is largely determined by age and comorbidities, but is also affected by other less well known factors. In Spain, most incidental cases of TB arise from the reactivation of remotely acquired latent infections and are favored by the aging of the population and the use of aggressive immunosuppressive therapies. The diagnosis and management of TB in these circumstances is often challenging. On the one hand, the atypical presentation with extrapulmonary involvement may delay diagnosis, and on the other, the toxicity and interactions of the antituberculous drugs frequently make treatment difficult. Immigration from resource-poor, high incidence TB countries, where the social and economic conditions are often suboptimal, adds a new challenge to the control of the disease in Spain. This chapter summarizes our current knowledge of epidemiological, clinical and treatment aspects of TB in particularly susceptible populations.

Impact of immigration on the molecular epidemiology of tuberculosis in Rhode Island

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 comparative examination of tuberculosis immigration medical screening programs from selected countries with high immigration and low tuberculosis incidence rates

BACKGROUND

Tuberculosis (TB) in migrants is an ongoing challenge in several low TB incidence countries since a large proportion of TB in these countries occurs in migrants from high incidence countries. To meet these challenges, several countries utilize TB screening programs. The programs attempt to identify and treat those with active and/or infectious stages of the disease. In addition, screening is used to identify and manage those with latent or inactive disease after arrival. Between nations, considerable variation exists in the methods used in migration-associated TB screening. The present study aimed to compare the TB immigration medical examination requirements in selected countries of high immigration and low TB incidence rates.

METHODS

Descriptive study of immigration TB screening programs.

RESULTS

16 out of 18 eligible countries responded to the written standardized survey and phone interview. Comparisons in specific areas of TB immigration screening programs included authorities responsible for TB screening, the primary objectives of the TB screening program, the yield of detection of active TB disease, screening details and aspects of follow up for inactive pulmonary TB. No two countries had the same approach to TB screening among migrants. Important differences, common practices, common problems, evidence or lack of evidence for program specifics were noted.

CONCLUSIONS

In spite of common goals, there is great diversity in the processes and practices designed to mitigate the impact of migration-associated TB among nations that screen migrants for the disease. The long-term goal in decreasing migration-related introduction of TB from high to low incidence countries remains diminishing the prevalence of the disease in those high incidence locations. In the meantime, existing or planned migration screening programs for TB can be made more efficient and evidenced based. Cooperation among countries doing research in the areas outlined in this study should facilitate the development of improved screening programs.

Tuberculosis screening and follow-up of asylum seekers in Norway: a cohort study

Background

About 80% of new tuberculosis cases in Norway occur among immigrants from high incidence countries. On arrival to the country all asylum seekers are screened with Mantoux test and chest x-ray aimed to identify cases of active tuberculosis and, in the case of latent tuberculosis, to offer follow-up or prophylactic treatment.

We assessed a national programme for screening, treatment and follow-up of tuberculosis infection and disease in a cohort of asylum seekers.

Methods

Asylum seekers ≥ 18 years who arrived at the National Reception Centre from January 2005 to June 2006, were included as the total cohort. Those with a Mantoux test ≥ 6 mm or positive x-ray findings were included in a study group for follow-up.

Data were collected from public health authorities in the municipality to where the asylum seekers had moved, and from hospital based internists in case they had been referred to specialist care.

Individual subjects included in the study group were matched with the Norwegian National Tuberculosis Register which receive reports of everybody diagnosed with active tuberculosis, or who had started treatment for latent tuberculosis.

Results

The total cohort included 4643 adult asylum seekers and 97.5% had a valid Mantoux test. At least one inclusion criterion was fulfilled by 2237 persons. By end 2007 municipal public health authorities had assessed 758 (34%) of them. Altogether 328 persons had been seen by an internist. Of 314 individuals with positive x-rays, 194 (62%) had seen an internist, while 86 of 568 with Mantoux ≥ 15, but negative x-rays (16%) were also seen by an internist. By December 31^st 2006, 23 patients were diagnosed with tuberculosis (prevalence 1028/100 000) and another 11 were treated for latent infection.

Conclusion

The coverage of screening was satisfactory, but fewer subjects than could have been expected from the national guidelines were followed up in the community and referred to an internist. To improve follow-up of screening results, a simplification of organisation and guidelines, introduction of quality assurance systems, and better coordination between authorities and between different levels of health care are all required.

Multidrug-resistant tuberculosis outbreak among US-bound Hmong refugees, Thailand, 2005

In January 2005, tuberculosis (TB), including multidrug-resistant TB (MDR TB), was reported among Hmong refugees who were living in or had recently immigrated to the United States from a camp in Thailand. We investigated TB and drug resistance, enhanced TB screenings, and expanded treatment capacity in the camp. In February 2005, 272 patients with TB (24 MDR TB) remained in the camp. Among 17 MDR TB patients interviewed, 13 were found to be linked socially. Of 23 MDR TB isolates genotyped, 20 were similar according to 3 molecular typing methods. Before enhanced screening was implemented, 46 TB cases (6 MDR TB) were diagnosed in the United States among 9,455 resettled refugees. After enhanced screening had begun, only 4 TB cases (1 MDR TB), were found among 5,705 resettled refugees. An MDR TB outbreak among US-bound refugees led to importation of disease; enhanced pre-immigration TB screening and treatment decreased subsequent importation.

Nonlinear pattern of pulmonary tuberculosis among migrants at entry in Kuwait: 1997-2006

Background

There is a paucity of published data on the pattern of pulmonary tuberculosis among migrant workers entering Middle Eastern countries particularly Kuwait. The objectives of this study were to use routine health surveillance data i) to estimate the prevalence of pulmonary tuberculosis among migrant workers at entry in Kuwait and ii) to determine the occurrence of any time trends in the proportions of pulmonary tuberculosis positive workers over the study period.

Methods

The monthly aggregates of daily number of migrants tested and the number of pulmonary tuberculosis cases detected during routine health examinations of migrant workers from tuberculosis high-prevalence countries were used to generate the monthly series of proportions (per 100,000) of pulmonary tuberculosis cases over 120 months between January 1, 1997 and December 31, 2006 and analysed using time series methods.

Results

The overall prevalence (per 100,000) of documented pulmonary tuberculosis cases among screened migrants was 198 (4608/2328582). Year-specific prevalence (per 100,000) of tuberculosis cases consistently declined from 456 (95% CI: 424 – 490) in 1997 to 124 (95% CI: 110 – 140) in 2002 before showing a steady increase up to 183 (95% CI: 169–197) in 2006. The second-order polynomial regression model revealed significant (P < 0.001) initial decline, followed by a significant (P < 0.001) increasing trend thereafter in monthly proportions of tuberculosis cases among migrant workers.

Conclusion

The proportions of documented tuberculosis cases among migrant workers showed a significant nonlinear pattern, with an initial decline followed by a significant increasing trend towards the end of the study period. These findings underscore the need to maintain the current policy of migrants' screening for tuberculosis at entry. The public health authorities in Kuwait and perhaps other countries in the region may consider complementing the current screening protocol with interferon-γ assays to detect migrants with latent Mycobacterium tuberculosis infection. An appropriate curative or preventive chemotherapy of detected tuberculosis cases may help in further minimizing the risk of local transmission of M. tuberculosis, while contributing in global efforts to control this public health menace.

Trends in tuberculosis reported from the Appalachian region: United States, 1993-2005

CONTEXT

Appalachia has been characterized by its poverty, a factor associated with tuberculosis, yet little is known about the disease in this region.

PURPOSE

To determine whether Appalachian tuberculosis risk factors, trends, and rates differ from the rest of the United States.

METHODS

Analysis of tuberculosis cases reported to the Centers for Disease Control and Prevention's National Tuberculosis Surveillance System (NTSS) within the 50 states and the District of Columbia from 1993 through 2005.

RESULTS

The 2005 rate of tuberculosis in rural Appalachia was 2.1/100,000, compared to 2.7/100,000 in urban Appalachia. Urban non-Appalachia had a 2005 tuberculosis rate of 5.4/100,000. Over the 13-year period, tuberculosis rates fell in Appalachia at an annual rate of 7.8%. In one age group (15- to 24-year-olds) the rates increased at an annual rate of 2.8%. Foreign-born Hispanics were the largest racial/ethnic group in this age group. When private providers gave exclusive care for tuberculosis disease, Appalachians were less likely to complete therapy in a timely manner when compared to non-Appalachians (OR 0.6, 95% CI 0.5-0.7).

CONCLUSIONS

Tuberculosis rates and trends are similar in urban and rural Appalachia. It is crucial for public health officials in Appalachia to address the escalating TB rate among 15- to 24-year-olds by focusing prevention efforts on the growing numbers of foreign-born cases. Due to the increased risk of treatment failure among Appalachians who do not seek care from the health department, public health authorities must ensure completion of treatment for patients who seek private providers.

TB perspectives among a sample of Mexicans in the United States: results from an ethnographic study

OBJECTIVE

A study was conducted to describe the sociocultural aspects of tuberculosis (TB) among Mexicans in the U.S. and to provide TB programs with practical recommendations for serving this population.

METHODS

In-depth, structured, open-ended interviews were conducted with 50 persons from Mexico living in the U.S. Local bilingual, bicultural researchers conducted the interviews with respondents recruited from TB clinics and surrounding communities. Both qualitative and quantitative strategies were used to analyze the data.

RESULTS

We found diverse TB perceptions and attitudes, but few were associated with specific participant characteristics. We detected widespread misperceptions about TB transmission and low perceptions of risk. Anticipated TB stigma among those with no history of disease was qualitatively greater than reported stigma among those who had TB disease. We also detected missed opportunities for TB education. Reported barriers to care included lack of transportation, limited clinic hours, cost of services, inconvenient clinic location, and communication problems with staff.

CONCLUSIONS

To address the diverse needs of Mexican-born clients, we recommend that TB programs provide culturally-appropriate, patient-centered care. We suggest several strategies aimed at raising risk awareness and reducing stigma. Finally, we encourage programs to facilitate access by providing language-appropriate services, extending clinic hours, and facilitating transportation.

Tuberculosis among foreign-born persons in Taiwan, 2002-2005

BACKGROUND/PURPOSE

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.

METHODS

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.

RESULTS

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%).

CONCLUSION

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.

Seasonality in pulmonary tuberculosis among migrant workers entering Kuwait

BACKGROUND

There is paucity of data on seasonal variation in pulmonary tuberculosis (TB) in developing countries contrary to recognized seasonality in the TB notification in western societies. This study examined the seasonal pattern in TB diagnosis among migrant workers from developing countries entering Kuwait.

METHODS

Monthly aggregates of TB diagnosis results for consecutive migrants tested between January I, 1997 and December 31, 2006 were analyzed. We assessed the amplitude (alpha) of the sinusoidal oscillation and the time at which maximum (theta degrees ) TB cases were detected using Edwards' test. The adequacy of the hypothesized sinusoidal curve was assessed by chi2 goodness-of-fit test.

RESULTS

During the 10 year study period, the proportion (per 100,000) of pulmonary TB cases among the migrants was 198 (4608/2328582), (95% confidence interval: 192 - 204). The adjusted mean monthly number of pulmonary TB cases was 384. Based on the observed seasonal pattern in the data, the maximum number of TB cases was expected during the last week of April (theta degrees = 112 degrees ; P < 0.001). The amplitude (+/- se) (alpha = 0.204 +/- 0.04) of simple harmonic curve showed 20.4% difference from the mean to maximum TB cases. The peak to low ratio of adjusted number of TB cases was 1.51 (95% CI: 1.39 - 1.65). The chi2 goodness-of-test revealed that there was no significant (P > 0.1) departure of observed frequencies from the fitted simple harmonic curve. Seasonal component explained 55% of the total variation in the proportions of TB cases (100,000) among the migrants.

CONCLUSION

This regularity of peak seasonality in TB case detection may prove useful to institute measures that warrant a better attendance of migrants. Public health authorities may consider re-allocation of resources in the period of peak seasonality to minimize the risk of Mycobacterium tuberculosis infection to close contacts in this and comparable settings in the region having similar influx of immigrants from high TB burden countries. Epidemiological surveillance for the TB risk in the migrants in subsequent years and required chemotherapy of detected cases may contribute in global efforts to control this public health menace.

Impact of immigration on the molecular epidemiology of Mycobacterium tuberculosis in a low-incidence country

RATIONALE

Programs to prevent the incidence rate of tuberculosis (TB) from increasing in many low-incidence countries are challenged by international travel and immigration from high-burden countries.

OBJECTIVES

The current study aimed to determine the effect of such immigration on the genetic diversity of Mycobacterium tuberculosis isolates in an entire nation's population during 1994-2005.

METHODS

A total of 3,131 patients were notified with TB during the 12-year period. Of these, 2,284 (73%) had TB verified by culture, and isolates from 2,173 (96%) of these were analyzed by IS6110 restriction fragment length polymorphism.

MEASUREMENTS AND MAIN RESULTS

Only 31% of the included strains were isolated from nonimmigrants, the remaining 69% were isolated from immigrants. Although the incidence increased throughout the period, the genetic diversity remained high. A total of 135 clusters were identified; the percentage of recent disease was reduced among nonimmigrants, and remained stable among the immigrants during the study period. Although 69% of the isolates originated from immigrants from high-incidence countries, the established TB control program in the receiving country was adequate for the prevention of disease transmission. On average per year, only 2 nonimmigrants and 13 immigrants developed disease as a result of infection within the country by imported M. tuberculosis.

CONCLUSIONS

Twelve years of M. tuberculosis importation as a result of immigration from high-incidence countries had little influence on the transmission of this pathogen in the receiving low-incidence country. To prevent future increase of transmission of TB, the current control strategies of low-incidence countries are adequate but must be maintained.

Risk of Progression to Active Tuberculosis Among Foreign-Born Persons With Latent Tuberculosis

BACKGROUND

Increased risk for tuberculosis (TB) disease has been identified in foreign-born persons in the United States, particularly during the first 5 years after their arrival in the United States. This could be explained by undetected TB disease at entry, increased prevalence of latent TB infection (LTBI), increased progression from LTBI to TB, or a combination of these factors.

METHODS

We performed a cluster analysis of TB cases in Boston and a case-control study of risk factors for TB with an unclustered isolate among Boston residents with LTBI to determine whether such persons have an increased risk for reactivation of disease.

RESULTS

Of 321 case patients with TB seen between 1996 and 2000, 133 isolates were clustered and 188 were not. In multivariate analysis, foreign birth was associated with an unclustered isolate (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.2 to 3.8; p < 0.01), while being a close contact of a TB case was negatively associated (OR, 0.22; 95% CI, 0.07 to 0.73; p = 0.02). When 188 TB patients with unclustered isolates were compared to 188 age-matched control subjects with LTBI, there was no association between the occurrence of TB and foreign birth (OR, 0.71; 95% CI, 0.42 to 1.3); among foreign-born persons, there was no association between the occurrence of TB and being in the United States <or= 5 years (OR, 0.90; 95% CI, 0.56 to 1.44).

CONCLUSIONS

We conclude that the increased risk for TB among foreign-born persons in the United States may be attributable to the increased prevalence of LTBI among foreign-born persons or the increased prevalence of active disease at arrival in the United States, but not to an increased rate of reactivation among persons with LTBI.

Épidémiologie de la tuberculose en France en 2005

This article presents results on cases of tuberculosis disease notified in France in 2005 by mandatory notification. In 2005, a total of 5,374 cases were notified in France, representing a rate of 8.9 cases per 100,000. The notification rate per 100,000 was below 10 in all French regions, except the Ile-de-France and French Guyana (with respective rates of 19.7/10(5) and 44.0/10(5)). Notification rates were higher in some population groups such as people born abroad (41.5/10(5)), especially those born in sub-Saharan Africa (160/10(5)), and those recently (<2 years) arrived in France (251/10(5)), in homeless people (214/10(5)), and in persons aged 80 years and over (21.7/10(5)). Pulmonary tuberculosis accounted for 73% of notified cases, 79% of which were contagious (positive direct examination of sputum, positive culture). Results from the notification of tuberculosis disease in 2005 indicate a continuing decrease of incidence in France. However, the high incidence in some population groups requires adapting public health actions to the needs of population groups more exposed to tuberculosis.

Pulmonary impairment after tuberculosis

BACKGROUND

Pulmonary impairment subsequent to a cure of pulmonary tuberculosis has been described only in selected populations.

METHODS

We compared pulmonary function in a case-control study of 107 prospectively identified patients with pulmonary tuberculosis who had completed at least 20 weeks of therapy and 210 patients with latent tuberculosis infection (LTBI).

RESULTS

Both groups had similar risk factors for pulmonary impairment. Impairment was present in 59% of tuberculosis subjects and 20% of LTBI control subjects. FVC, FEV1, FEV1/FVC ratio, and the midexpiratory phase of forced expiratory flow were significantly lower in the treated pulmonary tuberculosis patients than in the comparison group. Ten patients with a history of pulmonary tuberculosis (9.4%) had less than half of their expected vital capacity vs one patient (0.53%) in the LTBI group. Another 42 patients (39%) with tuberculosis had between 20% and 50% of the expected vital capacity vs 36 patients with LTBI (17%). After adjusting for risk, survivors of tuberculosis were 5.4 times more likely to have abnormal pulmonary function test results than were LTBI patients (p > 0.001; 95% confidence interval, 2.98 to 9.68). Birth in the United States (odds ratio [OR], 2.64; p = 0.003) and age (OR, 1.03; p = 0.005) increased the odds of impairment. Pulmonary impairment was more common in cigarette smokers; however, after adjusting for demographic and other risk factors, the difference did not reach statistical significance (p = 0.074).

CONCLUSIONS

These findings indicate that pulmonary impairment after tuberculosis is associated with disability worldwide and support more aggressive case prevention strategies and posttreatment evaluation. For many persons with tuberculosis, a microbiological cure is the beginning not the end of their illness.

The epidemiology of tuberculosis among primary refugee arrivals in Minnesota between 1997 and 2001

BACKGROUND

Minnesota (MN) is home to one of the highest number of refugees in the United States. The primary objective of this study was to evaluate the prevalence of latent and active tuberculosis (TB) infection in primary refugee arrivals to MN. Secondary objectives were to determine the association of TB infection with gender, age, and ethnicity of the refugees.

METHODS

A retrospective study of primary refugee arrivals to MN between January 1, 1997, and December 31, 2001, was conducted. Chi-square tests and logistic regression analyses were used to assess the association of TB infection with gender, age, and ethnicity.

RESULTS

Of the 9,842 refugees who had Mantoux test results, 4,990 (50.7%) had a positive test. A positive test was more common in men [odds ratio (OR) = 1.6; p < 0.0001], in Africans (OR = 1.6, p = <0.0001), and increased with 10-year age intervals (OR = 1.4; p < 0.0001). A total of 116 (0.8%) refugees received treatment for active TB. Active TB was more common in men (OR = 1.7; p = 0.006), African ethnicity (OR = 4.3; p < 0.0001), and increased with 10-year age intervals (OR = 1.1; p = 0.05).

CONCLUSIONS

Screening and treatment for latent and active TB should be actively managed among refugees resettling in the United States, as this is common and can have significant public health implications.

Tuberculosis among foreign-born persons in the United States: achieving tuberculosis elimination

RATIONALE

In the United States, the number of annual reported cases of tuberculosis (TB) among U.S.-born persons declined by 62% from 1993 to 2004, but increased by 5% among foreign-born persons. Over half of all reported cases of TB in the United States occur among foreign-born persons, most of these due to activation of latent TB infection (LTBI). Current guidelines recommend targeting only foreign-born persons who entered the United States within the previous 5 yr for LTBI testing.

OBJECTIVE

We sought to assess the epidemiologic basis for this guideline.

METHODS

We calculated TB case rates among foreign-born persons, stratified by duration of United States residence and world region of origin. We determined the number of cases using 2004 U.S. TB surveillance data, and calculated case rates using population data from the 2004 American Community Survey.

MEASUREMENTS AND MAIN RESULTS

In 2004, a total of 14,517 cases of TB were reported; 3,444 (24%) of these were among foreign-born persons who had entered the United States more than 5 yr previously. The rate of TB disease among foreign-born persons was 21.5/100,000, compared with 2.7/100,000 for U.S.-born persons, and varied by duration of residence and world region of origin.

CONCLUSIONS

Almost one-quarter of all TB cases in the United States occur among foreign-born persons who have resided in the United States for longer than 5 yr; case rates for such persons from selected regions of origin remain substantially elevated. To eliminate TB, we must address the burden of LTBI in this high-risk group.

Predictors of failure to complete treatment for latent tuberculosis infection

OBJECTIVE

Low rates of completion of treatment for latent tuberculosis infection (LTBI) limit its usefulness as a strategy for elimination of tuberculosis (TB) in the United States. This retrospective cohort study assessed predictors of completion of LTBI treatment among patients seen at an urban United States TB clinic in 1998.

METHODS

A retrospective cohort study of acceptance and completion of LTBI treatment among patients first seen in a TB clinic in 1998 was performed.

RESULTS

Of 2621 persons with a positive tuberculosis skin test (TST), 1723 were offered treatment and 1572 (91.2%) accepted. Of the 1572 who accepted, treatment was completed by 607 (38.6%). Of those persons who failed to complete treatment, 517/965 (54%) dropped out before the end of the first month of the course. Among 1375 persons under 35 years of age who initiated LTBI treatment, failure to complete was associated with birth in Haiti (OR=2.17, CI(95%) 1.49-3.17) or the Dominican Republic (OR=1.93, CI(95%) 1.08-3.43).

CONCLUSION

These results suggest that country-specific cultural and behavioral factors may contribute to failure to complete LTBI treatment, and that interventions to increase completion should focus on the first month after initiation.

Tuberculosis prevention for non-US-born pregnant women

OBJECTIVE

The purpose of this study was to evaluate whether non-US-born pregnant women receiving prenatal care are targeted for treatment of latent tuberculosis (TB) infection (LTBI) with isoniazid (INH) to prevent active TB.

STUDY DESIGN

This was a retrospective chart review study of 730 non-US-born pregnant women receiving care at 5 New York City prenatal clinics from 1999 to 2000.

RESULTS

Among 678 women with known tuberculin skin test (TST) status, 341 (50.3%) had a TST-positive result, including 200 who were newly diagnosed. Of 291 TST-positive women with no previous LTBI treatment or history of TB, 27 (9.3%) completed > or =6 months of INH. In a subset with detailed follow-up, the most important reasons for not completing treatment were nonreferral for evaluation of a TST-positive result (30.9%), not keeping the appointment (17.9%), and nonadherence with prescribed treatment (34.6%).

CONCLUSION

The prenatal setting represents a missed opportunity to link TST-positive non-US-born women with LTBI treatment and support for treatment completion.

Antibody profiles characteristic of Mycobacterium tuberculosis infection state

The relationship between specific antibody profiles and tuberculosis (TB) state was investigated by measuring serum antibody levels to six Mycobacterium tuberculosis antigens in human subjects grouped into four diagnostic categories: active disease, inactive (past) tuberculosis, latent infection without radiographic chest abnormalities, and infection free. Statistical data analyses showed that the latter two groups were serologically indistinguishable and that active tuberculosis and inactive tuberculosis were characterized by different antibody profiles. Antibodies to the 38-kDa antigen, alanine dehydrogenase, and Rv2626c were associated with active TB, while antibodies to the 16-kDa antigen, ferredoxin A, and ESAT-6 were associated with inactive TB. Thus, the targets of the immune response vary with tuberculosis state. The correlation between bacterial antigen production and infection stage was investigated in mice infected with M. tuberculosis by bacterial transcription profiling. It was found that levels of transcripts encoding the six M. tuberculosis antigens varied during infection. Together, the data indicate that antigen composition of tubercle bacilli varies with stage of infection and that immunoprofiling can distinguish between tuberculosis states.

Current issues in global tuberculosis control

Despite attempts to standardize tuberculosis (TB) control strategies, there remains wide variation in the selection and implementation of control strategies within and among nations. Some of this variation is appropriate; based on wide variations in the available resources, the prevalence of TB infection, the incidence of TB disease, the relative contribution of reactivation versus recent transmission to incident cases, and the rate of HIV co-infection. This review will discuss three controversial questions relevant to global TB control: (1) What is the role of the treatment of latent TB infection in global TB control? (2) What are successful strategies to control immigrant TB in low incidence countries? (3) What are successful strategies to control TB in persons with HIV infection?

American Thoracic Society/Centers for Disease Control and Prevention/Infectious Diseases Society of America: Controlling Tuberculosis in the United States

During 1993-2003, incidence of tuberculosis (TB) in the United States decreased 44% and is now occurring at a historic low level (14,874 cases in 2003). The Advisory Council for the Elimination of Tuberculosis has called for a renewed commitment to eliminating TB in the United States, and the Institute of Medicine has published a detailed plan for achieving that goal. In this statement, the American Thoracic Society (ATS), Centers for Disease Control and Prevention (CDC), and the Infectious Diseases Society of America (IDSA) propose recommendations to improve the control and prevention of TB in the United States and to progress toward its elimination. This statement is one in a series issued periodically by the sponsoring organizations to guide the diagnosis, treatment, control, and prevention of TB. This statement supersedes the previous statement by ATS and CDC, which was also supported by IDSA and the American Academy of Pediatrics (AAP). This statement was drafted, after an evidence-based review of the subject, by a panel of representatives of the three sponsoring organizations. AAP, the National Tuberculosis Controllers Association, and the Canadian Thoracic Society were also represented on the panel. This statement integrates recent scientific advances with current epidemiologic data, other recent guidelines from this series, and other sources into a coherent and practical approach to the control of TB in the United States. Although drafted to apply to TB-control activities in the United States, this statement might be of use in other countries in which persons with TB generally have access to medical and public health services and resources necessary to make a precise diagnosis of the disease; achieve curative medical treatment; and otherwise provide substantial science-based protection of the population against TB. This statement is aimed at all persons who advocate, plan, and work at controlling and preventing TB in the United States, including persons who formulate public health policy and make decisions about allocation of resources for disease control and health maintenance and directors and staff members of state, county, and local public health agencies throughout the United States charged with control of TB. The audience also includes the full range of medical practitioners, organizations, and institutions involved in the health care of persons in the United States who are at risk for TB.

The health of immigrants and refugees in Canada

Canada admits between more than 200,000 immigrants every year. National policy emphasizes rigorous selection to ensure that Canada admits healthy immigrants. However, remarkably little policy is directed to ensuring that they stay healthy. This neglect is wrong-headed: keeping new settlers healthy is just, humane, and consistent with national self-interest. By identifying personal vulnerabilities, salient resettlement stressors that act alone or interact with predisposition in order to create health risk, and the personal and social resources that reduce risk and promote well-being, health research can enlighten policy and practice. However, the paradigms that have dominated immigrant health research over the past 100 years--the "sick" and "healthy immigrant," respectively--have been inadequate. Part of the problem is that socio-political controversy has influenced the questions asked about immigrant health, and the manner of their investigation. Beginning with a review of studies that point out the shortcomings of the sick immigrant and healthy immigrant paradigms, this article argues that an interaction model that takes into account both predisposition and socio-environmental factors, provides the best explanatory framework for extant findings, and the best guide for future research. Finally, the article argues that forging stronger links between research, policy and the delivery of services will not only help make resettlement a more humane process, it will help ensure that Canada benefits from the human capital that its newest settlers bring with them.

Incident tuberculosis among recent US immigrants and exogenous reinfection

Mathematical models and molecular epidemiologic investigation support the argument that exogenous reinfection plays an important role in tuberculosis transmission in high-incidence regions. We offer additional data from tuberculosis cases among recent US immigrants which strengthen the claim that reinfection in areas of intense transmission is common.