Tuberculosis in the foreign-born population of Tarrant county, Texas by immigration status

A GIS-Based Artificial Neural Network Model for Spatial Distribution of Tuberculosis across the Continental United States

Despite the usefulness of artificial neural networks (ANNs) in the study of various complex problems, ANNs have not been applied for modeling the geographic distribution of tuberculosis (TB) in the US. Likewise, ecological level researches on TB incidence rate at the national level are inadequate for epidemiologic inferences. We collected 278 exploratory variables including environmental and a broad range of socio-economic features for modeling the disease across the continental US. The spatial pattern of the disease distribution was statistically evaluated using the global Moran’s I, Getis–Ord General G, and local Gi* statistics. Next, we investigated the applicability of multilayer perceptron (MLP) ANN for predicting the disease incidence. To avoid overfitting, L1 regularization was used before developing the models. Predictive performance of the MLP was compared with linear regression for test dataset using root mean square error, mean absolute error, and correlations between model output and ground truth. Results of clustering analysis showed that there is a significant spatial clustering of smoothed TB incidence rate (p < 0.05) and the hotspots were mainly located in the southern and southeastern parts of the country. Among the developed models, single hidden layer MLP had the best test accuracy. Sensitivity analysis of the MLP model showed that immigrant population (proportion), underserved segments of the population, and minimum temperature were among the factors with the strongest contributions. The findings of this study can provide useful insight to health authorities on prioritizing resource allocation to risk-prone areas.

Screening for tuberculosis in migrants and visitors from high-incidence settings: present and future perspectives

In most settings with a low incidence of tuberculosis (TB), foreign-born people make up the majority of TB cases, but the distribution of the TB risk among different migrant populations is often poorly quantified. In addition, screening practices for TB disease and latent TB infection (LTBI) vary widely. Addressing the risk of TB in international migrants is an essential component of TB prevention and care efforts in low-incidence countries, and strategies to systematically screen for, diagnose, treat and prevent TB among this group contribute to national and global TB elimination goals.This review provides an overview and critical assessment of TB screening practices that are focused on migrants and visitors from high to low TB incidence countries, including pre-migration screening and post-migration follow-up of those deemed to be at an increased risk of developing TB. We focus mainly on migrants who enter the destination country via application for a long-stay visa, as well as asylum seekers and refugees, but briefly consider issues related to short-term visitors and those with long-duration multiple-entry visas. Issues related to the screening of children and screening for LTBI are also explored.

Role of the Health Department in Tuberculosis Prevention and Control-Legal and Public Health Considerations

Because tuberculosis is caused by an infectious organism that is spread from person to person through the air, public health measures are essential to control the disease. There are three priority strategies for tuberculosis prevention and control in the United States: (i) identifying and treating persons who have tuberculosis disease; (ii) finding persons exposed to infectious tuberculosis patients, evaluating them for Mycobacterium tuberculosis infection and disease, and providing subsequent treatment, if appropriate; and (iii) testing populations at high risk for latent tuberculosis infection (LTBI) and treating those persons who are infected to prevent progression to disease. These strategies for prevention and control of tuberculosis are discussed in a framework containing the following important topics: historical and epidemiological context of tuberculosis control, organization of public health tuberculosis control programs, legal basis for public health authority, conducting overall planning and development of policy, identifying persons who have clinically active tuberculosis, evaluation of immigrants, managing persons who have or who are suspected of having disease, medical consultation, interjurisdictional referrals, identifying and managing persons infected with Mycobacterium tuberculosis, providing laboratory and diagnostic services, collecting and analyzing data, and providing training and education. This chapter describes the role of the health department in the context of these components. This discussion is primarily applicable to tuberculosis prevention and control programs in the United States.

Use of Transnational Services to Prevent Treatment Interruption in Tuberculosis-Infected Persons Who Leave the United States

Scale up of such services is possible and encouraged because of potential health gains and reduced healthcare costs.

A major problem resulting from interrupted tuberculosis (TB) treatment is the development of drug-resistant TB, including multidrug-resistant TB (MDR TB), a more deadly and costly-to-treat form of the disease. Global health systems are not equipped to diagnose and treat the current burden of MDR TB. TB-infected foreign visitors and temporary US residents who leave the country during treatment can experience treatment interruption and, thus, are at greater risk for drug-resistant TB. Using epidemiologic and demographic data, we estimated TB incidence among this group, as well as the proportion of patients referred to transnational care–continuity and management services during relocation; each year, ≈2,827 visitors and temporary residents are at risk for TB treatment interruption, 222 (8%) of whom are referred for transnational services. Scale up of transnational services for persons at high risk for treatment interruption is possible and encouraged because of potential health gains and reductions in healthcare costs for the United States and receiving countries.

Improving the uptake of pre-travel health advice amongst migrant Australians: exploring the attitudes of primary care providers and migrant community groups

Background

Migrant travellers who return to their country of origin to visit family and friends (VFR) are less likely to seek travel-related medical care and are less likely to adhere to recommended medications and travel precautions. Through this study, we aimed to get an understanding of the views of stakeholders from community migrant centres and primary care providers on barriers for migrants, particularly from non-English speaking backgrounds, in accessing travel health advice and the strategies that could be used to engage them.

Methods

A qualitative study involving 20 semi-structured interviews was undertaken in Sydney, Australia between January 2013 and September 2014. Thematic analysis was undertaken.

Results

Language barriers, a lower perceived risk of travel-related infections and the financial costs of seeking pre-travel health care were nominated as being the key barriers impacting on the uptake of pre-travel health advice and precautions. To overcome pre-existing language barriers, participants advocated for the use of bilingual community educators, community radio, ethnic newspapers and posters in the dissemination of pre-travel health information.

Conclusions

Travel is a major vector of importation of infectious diseases into Australia, and VFR travellers are at high risk of infection. Collaboration between the Government, primary care physicians, migrant community groups and migrants themselves is crucial if we are to be successful in reducing travel-related risks among this subgroup of travellers.

Incidence of Tuberculosis and Amyloidosis among Sudanese Patients Presented with Enlarged Nodes

Objectives. To determine the incidence of tuberculous lymphadenitis and amyloidosis in enlarged lymph nodes (LN). Methodology. A retrospective study was carried out in the department of pathology at the Faculty of Medicine, University of Kordofan, during one-year period. The study included a group of 103 patients with lymphadenopathy. Results. Of the 103 cases with enlarged neck nodes, 35 (34%) had tuberculous lymphadenitis. Sixteen (46%) cases were males and 19 (54%) cases were females. Out of the 103 patients, amyloidosis was diagnosed in 9/103 (8.7%). Out of the 9 positive cases, 2/9 (22.2%) were males and 7/9 (77.8%) were females. Conclusion. There is high incidence of tuberculous lymphadenitis in patients with enlarged LN in developing countries like North Sudan. Amyloidosis should not be ignored when investigating enlarged LN.

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 lymphadenitis in Southwest Ethiopia: a community based cross-sectional study

BACKGROUND

In Ethiopia where there is no strong surveillance system and diagnostic facilities are limited, the real burden of tuberculosis (TB) lymphadenitis is not well known. Therefore, we conducted a study to estimate the prevalence of TB lymphadenitis in Southwest Ethiopia.

METHODS

A community based cross-sectional study was conducted from February to March 2009 in the Gilgel Gibe field research area. A total of 30,040 individuals 15 years or older in 10,882 households were screened for TB lymphadenitis. Any individual 15 years or older with lumps in the neck, armpits or groin up on interview were considered TB lymphadenitis suspect. The diagnosis of TB lymphadenitis was established when acid fast bacilli (AFB) smear microscopy of fine needle aspiration (FNA) sample, culture or cytology suggested TB. HIV counseling and testing was offered to all TB lymphadenitis suspects. Descriptive and bivariate analysis was done using SPSS version 15.

RESULTS

Complete data were available for 27,597 individuals. A total of 87 TB lymphadenitis suspects were identified. Most of the TB lymphadenitis suspects were females (72.4%). Sixteen cases of TB lymphadenitis were confirmed. The prevalence of TB lymphadenitis was thus 58.0 per 100,000 people (16/27,597) (95% CI 35.7-94.2). Individuals who had a contact history with chronic coughers (OR 5.58, 95% CI 1.23-25.43) were more likely to have TB lymphadenitis. Lymph nodes with caseous FNA were more likely to be positive for TB lymphadenitis (OR 5.46, 95% CI 1.69-17.61).

CONCLUSION

The prevalence of TB lymphadenitis in Gilgel Gibe is similar with the WHO estimates for Ethiopia. Screening of TB lymphadenitis particularly for family members who have contact with chronic coughers is recommended. Health extension workers could be trained to screen and refer TB lymphadenitis suspects using simple methods.

Estimating the impact of newly arrived foreign-born persons on tuberculosis in the United States

BACKGROUND

Among 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 FINDINGS

We 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/SIGNIFICANCE

Newly 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.

Outbreak of tuberculosis among Guatemalan immigrants in rural Minnesota, 2008

OBJECTIVES

We described the outbreak investigation and control measures after the Minnesota Department of Health identified a cluster of tuberculosis (TB) cases among Guatemalan immigrants within three rural Minnesota counties in August 2008.

METHODS

TB cases were diagnosed by tuberculin skin test followed by chest radiography and sputum testing for Mycobacterium tuberculosis (M. tuberculosis). We reviewed medical records, interviewed patients, and completed a contact investigation for each infectious case. We used isolate genotyping to confirm epidemiologic links between cases.

RESULTS

The index case was a six-month-old U.S.-born male with Guatemalan parents. Although he experienced four months of cough and fever, TB was not considered at two medical visits but was diagnosed upon hospitalization in May 2008. The presumed source of infection was a Guatemalan male aged 25 years who sang in a band that practiced in the infant's house and whose pulmonary TB was diagnosed at hospitalization in June 2008, despite his having sought medical attention for symptoms seven months earlier. Among the 16 identified TB cases, 14 were outbreak-related. Three genetically distinct M. tuberculosis strains circulated. Of 150 contacts of the singer, 62 (41%) had latent TB infection and 13 (9%), including 10 children, had TB disease.

CONCLUSIONS

In this outbreak, delayed diagnoses contributed to M. tuberculosis transmission. Isolate genotyping corroborated the social links between outbreak-related patients. More timely diagnosis of TB among immigrants and their children can prevent TB transmission among communities in rural, low-incidence areas that might have limited resources for contact investigations.

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.

Health status of visitors and temporary residents, United States

Human mobility has always been associated with the spread of infection, and mobility of nonimmigrant visitors and temporary residents to the United States is increasing, from approximately 12 million in 1987 to approximately 37 million in 2007. Lack of information about the health status of these populations upon arrival and their need for and use of medical services in the United States hinders development of public health policy, education, and provision of adequate clinical care. After these issues and needs are clarified, intervention programs should be developed to increase access and decrease the disparities of care experienced by these populations.

The challenge of multisite epidemiologic studies in diverse populations: design and implementation of a 22-site study of tuberculosis in foreign-born people

OBJECTIVES

We designed a population-based study of the epidemiology of tuberculosis among foreign-born people in the U.S. and Canada. Challenges included standardizing recruitment and data entry at 22 sites, enrolling individuals who did not speak English and may be undocumented, and obtaining clearance from 36 institutional review boards (IRBs).

METHODS

We used stratified sampling to recruit patients through the Tuberculosis Epidemiologic Studies Consortium, a research consortium funded by the Centers for Disease Control and Prevention. Because recruitment sites were overseen by more than 30 local IRBs, we developed a simple process to designate a central IRB. We translated instruments into 10 main languages, arranged for fast translation of consent "short forms" into other languages, used one telephone interpretation service at all sites, and provided extensive interviewer training including mock interviews with simulated patients.

RESULTS

We interviewed 1,696 participants in 19 states and provinces. Participants from 99 countries were interviewed in 40 languages. Twenty-three percent did not speak English at all; 64% needed an interpreter. More than 20% of participants reported they were undocumented. Participants' age, gender, and birthplaces were broadly similar to the target populations. One-third of local IRBs used the central IRB.

CONCLUSIONS

Special confidentiality protections, substantial resources for translation and interpretation, and a centralized IRB made possible the recruitment of a representative sample of foreign-born people. The approaches may be applicable to studies of other diseases in multinational populations in the U.S. and Canada.

Impact on and use of an inner-city London Infectious Diseases Department by international migrants: a questionnaire survey

Background

The UK has witnessed a considerable increase in immigration in the past decade. Migrant may face barriers to accessing appropriate health care on arrival and the current focus on screening certain migrants for tuberculosis on arrival is considered inadequate. We assessed the implications for an inner-city London Infectious Diseases Department in a high migrant area.

Methods

We administered an anonymous 20-point questionnaire survey to all admitted patients during a 6 week period. Questions related to sociodemographic characteristics and clinical presentation. Analysis was by migration status (UK born vs overseas born).

Results

111 of 133 patients completed the survey (response rate 83.4%). 58 (52.2%) were born in the UK; 53 (47.7%) of the cohort were overseas born. Overseas-born were over-represented in comparison to Census data for this survey site (47.7% vs 33.6%; proportional difference 0.142 [95% CI 0.049–0.235]; p = 0.002): overseas born reported 33 different countries of birth, most (73.6%) of whom arrived in the UK pre-1975 and self-reported their nationality as British. A smaller number (26.4%) were new migrants to the UK (≤10 years), mostly refugees/asylum seekers. Overseas-born patients presented with a broad range and more severe spectrum of infections, differing from the UK-born population, resulting in two deaths in this group only. Presentation with a primary infection was associated with refugee/asylum status (n = 8; OR 6.35 [95% CI 1.28–31.50]; p = 0.023), being a new migrant (12; 10.62 [2.24–50.23]; p = 0.003), and being overseas born (31; 3.69 [1.67–8.18]; p = 0.001). Not having registered with a primary-care physician was associated with being overseas born, being a refugee/asylum seeker, being a new migrant, not having English as a first language, and being in the UK for ≤5 years. No significant differences were found between groups in terms of duration of illness prior to presentation or duration of hospitalisation (mean 11.74 days [SD 12.69]).

Conclusion

Migrants presented with a range of more severe infections, which suggests they face barriers to accessing appropriate health care and screening both on arrival and once settled through primary care services. A more organised and holistic approach to migrant health care is required.

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.

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.

Demographic pattern and clinical characteristics of patients with smear- positive pulmonary tuberculosis in kuwait

OBJECTIVE

The aim of this study was to document various clinical factors that are likely to be of help in the control of tuberculosis in Kuwait.

SUBJECTS AND METHODS

Details of patients with sputum positive for acid-fast bacilli in the period from January 1998 to December 2000 were collected retrospectively from the case records and population statistics from government sources. The data were then tabulated and analyzed.

RESULTS

Of the 526 cases, 83.5% were expatriates and 16.5% Kuwaiti; 373 (70.9%) were male. Of the expatriates, 66.7% were from Asia and the Far East, 5.7% were > or =60 years. The annual incidence was 8.34 per 100,000 population. The lowest incidence was observed in the Jahrah governorate with an overall incidence of 5 (2.0 among Kuwaitis and 6.4 among expatriates) per 100,000 population. The highest incidence overall (10.2) and among Kuwaitis (4.1) was observed in the Farwaniya governorate, while the highest incidence among expatriates was seen in the Capital governorate (13.4). Radiologically, 94 (19.5%) had minimal, 246 (51.5%) had moderately advanced and 141 (29.3%) far-advanced disease. The majority of the patients (72%) had only + status for AFB in the smear. Hypercalcemia (25.7%), hyponatremia (22.15%) and hyperglycemia (29.9%) were common in the patients. Mean serum albumin was low (28.7 +/- 5.5 g/l). Two hundred and forty-seven (47.2%) were declared cured while 116 (22.2%) completed treatment. Comparison between nationals and expatriates showed a significant difference only for age, smoking status, defaulter rate and place of residence.

CONCLUSION

The lowest regional incidence was found in the Jahrah governorate. Both biochemical abnormalities and radiologically advanced presentations were common. Disease pattern and response to treatment was purely individual and did not differ with respect to nationality or race.

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.

Screening of Immigrants and Refugees for Pulmonary Tuberculosis in San Diego County, California

STUDY OBJECTIVES

To evaluate the outcomes of a tuberculosis (TB) screening program for recent immigrants to San Diego County, CA, and to compare the demographic and clinical characteristics of pulmonary TB cases occurring in recently arrived foreign-born persons detected through this screening with those of similar cases found through routine surveillance.

DESIGN

Retrospective review of computer databases and medical records.

SETTING

Local public health department.

PATIENTS

Recent immigrants and refugees classified as TB suspects in their country of departure and foreign-born patients with active TB detected through routine surveillance.

RESULTS

Five hundred seventy-one of 658 immigrants and refugees (87%) of completed screening. Thirty-nine subjects (7%) were found to have active TB, and 433 subjects (76%) were found to have latent TB. A diagnosis of active TB was associated with age of 25 to 44 years (odds ratio, 3.6; 95% confidence interval, 1.1 to 11.6) and A (odds ratio, 25.7; 95% confidence interval, 1.3 to 512.2) or B1 classifications (odds ratio, 4.3; 95% confidence interval, 1.5 to 12.5). Cases detected through screening comprised 12% of all reported foreign-born persons with active TB. Compared to other recently arrived foreign-born persons with active TB, those detected through immigrant screening were more likely to be Asian and born in the Philippines and less likely to have advanced disease.

CONCLUSIONS

Most immigrants and refugees classified as TB suspects by foreign screening completed the US screening process, which had a high yield for detecting active and latent TB. Only a minority of foreign-born persons (12%) with active TB were discovered through this program, however, and additional measures are needed to facilitate early case finding in other foreign-born populations.

Global drug-resistance patterns and the management of latent tuberculosis infection in immigrants to the United States

BACKGROUND

In the United States, an increasingly disproportionate burden of tuberculosis among the foreign-born population has led to calls for improvements in the detection and treatment of latent infection in new immigrants. Current treatment guidelines do not take into account global differences in drug-resistance patterns or their implications for the treatment of immigrants. The use of multinational surveillance systems to guide the management of latent infection according to region-specific drug-resistance profiles could improve the efficiency of efforts to reduce the burden of tuberculosis in immigrants to the United States.

METHODS

We constructed a decision-analysis model by using a hypothetical cohort of all documented immigrants entering the United States from developing nations. Region-specific drug-resistance profiles were derived from data on 30,388 cases of infection. The model examined the effectiveness and cost effectiveness of four strategies: no intervention or tuberculin skin testing followed by treatment with isoniazid, treatment with rifampin, or treatment with rifampin plus pyrazinamide for those with a positive test result.

RESULTS

A strategy of detecting and treating latent tuberculosis infection was cost-saving among immigrants from Mexico, Haiti, sub-Saharan Africa, South Asia, and developing nations in East Asia and the Pacific. This strategy was highly cost effective among immigrants from other developing nations. Rifampin plus pyrazinamide was the preferred strategy for treating latent infection in immigrants from Vietnam, Haiti, and the Philippines.

CONCLUSIONS

For new immigrants to the United States from developing nations, a strategy of detecting and treating latent tuberculosis infection would lead to substantial health and economic benefits. Because of the high prevalence of resistance to isoniazid, treatment with a rifampin-containing regimen should be strongly considered for immigrants from Vietnam, Haiti, and the Philippines.

A decision tree for tuberculosis contact investigation

The University of Alabama at Birmingham and the Alabama Department of Public Health recently developed a logistic regression model showing those variables that are most likely to predict a positive tuberculin skin test in contacts of tuberculosis cases. However, translating such a model into field application requires a stepwise approach. This article describes a decision tree developed to assist public health workers in determining which contacts are most likely to have a positive tuberculin skin test. The Classification and Regression Tree analysis was performed on 292 consecutive cases and their 2,941 contacts seen by the Alabama Department of Public Health from January 1, 1998, to October 15, 1998. Several decision trees were developed and were then tested using prospectively collected data from 366 new tuberculosis cases and their 3,162 contacts from October 15, 1998, to April 30, 2000. Testing showed the trees to have sensitivities of 87-94%, specificities of 22-28%, and false-negative rates between 7 and 10%. The use of the decision trees would decrease the number of contacts investigated by 17-25% while maintaining a false-negative rate that was close to that of the presumed background rate of latent tuberculosis infection in the state of Alabama.

Tuberculosis control in a border state. Treatment of the foreign-born

As the epidemiology of TB in the United States changes, with more foreign-born and fewer native-born residents developing the disease, treatment can be expected to become more complicated and expensive.