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

Drivers determining tuberculosis disease screening yield in four European screening programmes: a comparative analysis

BACKGROUND

The World Health Organization End TB Strategy emphasises screening for early diagnosis of tuberculosis (TB) in high-risk groups, including migrants. We analysed key drivers of TB yield differences in four large migrant TB screening programmes to inform TB control planning and feasibility of a European approach.

METHODS

We pooled individual TB screening episode data from Italy, the Netherlands, Sweden and the UK, and analysed predictors and interactions for TB case yield using multivariable logistic regression models.

RESULTS

Between 2005 and 2018 in 2 302 260 screening episodes among 2 107 016 migrants to four countries, the programmes identified 1658 TB cases (yield 72.0 (95% CI 68.6-75.6) per 100 000). In logistic regression analysis, we found associations between TB screening yield and age (≥55 years: OR 2.91 (95% CI 2.24-3.78)), being an asylum seeker (OR 3.19 (95% CI 1.03-9.83)) or on a settlement visa (OR 1.78 (95% CI 1.57-2.01)), close TB contact (OR 12.25 (95% CI 11.73-12.79)) and higher TB incidence in the country of origin. We demonstrated interactions between migrant typology and age, as well as country of origin. For asylum seekers, the elevated TB risk remained similar above country of origin incidence thresholds of 100 per 100 000.

CONCLUSIONS

Key determinants of TB yield included close contact, increasing age, incidence in country of origin and specific migrant groups, including asylum seekers and refugees. For most migrants such as UK students and workers, TB yield significantly increased with levels of incidence in the country of origin. The high, country of origin-independent TB risk in asylum seekers above a 100 per 100 000 threshold could reflect higher transmission and re-activation risk of migration routes, with implications for selecting populations for TB screening.

Country differences and determinants of yield in programmatic migrant TB screening in four European countries

INTRODUCTION The WHO End TB Strategy emphasises early diagnosis and screening of TB in high-risk groups, including migrants. We analysed TB yield data from four large migrant TB screening programmes to inform TB policy.METHODS We pooled routinely collected individual TB screening episode data from Italy, the Netherlands, Sweden and the United Kingdom under the European Union Commission E-DETECT.TB grant, described characteristics of the screened population, and analysed TB case yield.RESULTS We collected data on 2,302,260 screening episodes among 2,107,016 migrants, mostly young adults aged 18-44 years (77.8%) from Asia (78%) and Africa (18%). There were 1,658 TB cases detected through screening, with substantial yield variation (per 100,000): 201.1 for Sweden (95% confidence intervals CI 111.4-362.7), 68.9 (95% CI 65.4-72.7) for the United Kingdom, 83.2 (95% CI 73.3-94.4) for the Netherlands and 653.6 (95% CI 445.4-958.2) in Italy. Most TB cases were notified among migrants from Asia (n = 1,206, 75/100,000) or Africa (n = 370, 76.4/100,000), and among asylum seekers (n = 174, 131.5/100,000), migrants to the Netherlands (n = 101, 61.9/100,000) and settlement visa migrants to the United Kingdom (n = 590, 120.3/100,000).CONCLUSIONS We found considerable variations in yield across programmes, types of migrants and country of origin. These variations may be partly explained by differences in migration patterns and programmatic characteristics.

Detecting Mycobacterium tuberculosis Infection in Children Migrating to Australia

In 2015, Australia updated premigration screening for tuberculosis (TB) disease in children 2-10 years of age to include testing for infection with Mycobacterium tuberculosis and enable detection of latent TB infection (LTBI). We analyzed TB screening results in children <15 years of age during November 2015-June 2017. We found 45,060 child applicants were tested with interferon-gamma release assay (IGRA) (57.7% of tests) or tuberculin skin test (TST) (42.3% of tests). A total of 21 cases of TB were diagnosed: 4 without IGRA or TST, 10 with positive IGRA or TST, and 7 with negative results. LTBI was detected in 3.3% (1,473/44,709) of children, for 30 applicants screened per LTBI case detected. LTBI-associated factors included increasing age, TB contact, origin from a higher TB prevalence region, and testing by TST. Detection of TB and LTBI benefit children, but the updated screening program's effect on TB in Australia is likely to be limited.

Invited Commentary: The Role of Tuberculosis Screening Among Migrants to Low-Incidence Settings in (Not) Achieving Elimination

The cost-effectiveness of migrant tuberculosis prevention programs is highly relevant to many countries with low tuberculosis incidence as they attempt to eliminate the disease. Dale et al. (Am J Epidemiol. 2022;191(2):255-270) evaluated strategies for tuberculosis infection screening and treatment among new migrants to Australia. Screening for infection before migration, and then administering preventive treatment after arrival, was more cost-effective than performing both screening and treatment after arrival. From the Australian health payer perspective, the improved cost-effectiveness of premigration screening partly reflected the shift of screening costs to migrants, which may raise ethical concerns. Key sensitivity analyses highlighted the influence of health disutility associated with tuberculosis preventive treatment, and of posttreatment sequelae of tuberculosis disease. Both considerations warrant greater attention in future research. For all strategies, the impact on tuberculosis incidence among migrants was modest (<15%), suggesting enhanced migrant screening will not achieve tuberculosis elimination in low-incidence settings. This emphasizes the need to increase investment and effort in global tuberculosis prevention and care, which will ultimately reduce the prevalence of tuberculosis infection and therefore the risk of tuberculosis disease among migrants. Such efforts will benefit high and low tuberculosis incidence countries alike, and advance all countries further toward tuberculosis elimination.

"Diagnosis on the Dock" project: A proactive screening program for diagnosing pulmonary tuberculosis in disembarking refugees and new SEI model

OBJECTIVE

From 2011 to 2017, the total number of refugees arriving in Europe, particularly in Italy, climbed dramatically. Our aim was to diagnose pulmonary TB in migrants coming from the African coast using a clinical-based port of arrival (PoA) screening program.

METHODS

From 2016 to 2018, migrants coming via the Mediterranean Route were screened for body temperature and the presence of cough directly on the dock: if they were feverish with productive cough, their sputum was examined with NAAT; with a dry cough, they underwent Chest-X-ray (CXR). Those migrants with positive NAAT or CXR suggestive for TB were admitted to our ward. In addition, we plotted an SEI simulation of our project to evaluate the epidemiological impact of our screening.

RESULTS

Out of 33.676 disembarking migrants, 314 (0.9%) had fever and cough: 80 (25.47%) with productive cough underwent NAAT in sputum, and 16 were positive for TB; 234 (74.52%) with dry cough had a CXR examination, and 39 were suggestive of TB, later confirmed by mycobacterial culture. The SEI-new model analysis demonstrated that our screening program significantly reduced TB spreading all over the country.

CONCLUSIONS

For possible future high migrant flows, PoA screening for TB has to be considered feasible and effective in decreasing TB spreading.

Role of Immigration in Tuberculosis Transmission to Iran: A Systematic Review

Background:

Today, because of increasing immigration and the prevalence of drug-resistant tuberculosis in Iran, identifying intra-community cases is necessary in the country. It will be possible through the use of molecular epidemiologic methods. In this inquiry, in order to determine the role of immigrants in the transmission of specific strains to Iran, the studies have been examined which had been conducted based on molecular epidemiologic methods among Iranians and non-Iranians people.

Methods:

All studies from 1997 to the end of March 2017 were examined in three databases of PubMed, Scopus, and Google Scholar and finally, 16 studies were selected.

Results:

The common clustering rate between Iranians and non-Iranians was determined to be 19.8, and the intra-community recent transmission rate was from 0% to 49% with average of 18.1%. The rate of multidrug-resistant tuberculosis (MDR-TB) was 12.5%, which was higher among immigrants, especially Afghans, and a significant number of the strains were Beijing.

Conclusions:

The studies have shown that migrants, especially Afghans, are more effective in transmitting specific strains of tuberculosis to migratory areas. To control tuberculosis, it is necessary to register of immigrant's health information, while enter to the country, so that, by doing appropriate diagnostic tests, the curing the patients, the transmission of tuberculosis to the country would be prevented.

Tuberculosis treatment outcomes of non-citizen migrants: Israel compared to other high-income countries

BACKGROUND

In TB low incidence countries, the outcome of TB treatment among non-citizen migrants from endemic countries affects ability to eliminate TB. This study compares TB treatment outcomes among non-citizen migrants in select pre-elimination country based on their policies for non-citizen migrant TB patients in order to determine how policy affects TB outcomes.

METHODS

A literature review was conducted via PUBMED, MEDLINE (2000-2017) on TB policy among non-citizen migrants and treatment outcome. Treatment outcome among migrants diagnosed in Israel during 2000-2014 was analysed.

RESULTS

In total, 18 publications met the inclusion criteria. All the countries reviewed except the United States offered free TB treatment to undocumented migrants. Successful TB treatment outcome for non-citizen migrants in Israel was 87%, the Netherlands was 90.7%, the UK was 82.1%, and outcomes in the US and Australia were not published.

CONCLUSIONS

There is a need to standardize results based on international definitions of migrants, asylum seekers, and refugees in order to determine status-specific barriers and to facilitate international comparisons. Policies insuring free access to TB care for non-citizen migrants are an important element for TB elimination in low incidence countries.

Reconstructing the population dynamics of foreign residents in Japan to estimate the prevalence of infection with Mycobacterium tuberculosis

Among newly notified tuberculosis cases in Japan, both the number and the proportion of foreign-born cases have steadily increased over time. As Japan prepares to introduce pre-entry tuberculosis screening for foreign-born persons entering Japan, various epidemiological evidence is needed to evaluate its effectiveness, including the prevalence of tuberculosis among current foreign residents in Japan, by country of birth. Yet as of today, even the underlying population dynamics has yet to be quantified. The present study therefore aimed to firstly reconstruct the demographic prevalence of foreign residents by the length of stay in Japan and by country of birth, and secondly, to estimate the prevalence of infection from notification data among foreign residents in Japan. We employed the McKendrick partial differential equation model to reconstruct the dynamics among six Asian countries which account for 80% of foreign-born tuberculosis patients notified in Japan i.e. China, the Philippines, Vietnam, Nepal, Indonesia, and Myanmar. Compared with China and the Philippines, the recent remarkable increase in the number of residents who had arrived within 5 years from Myanmar and Vietnam was identified. Assuming that the risk of primary tuberculosis given infection is 5%, the estimated prevalence of infection ranged from 3.5% to 21.3%, and all the estimates were more than three times greater than the crude estimate that ignored the time since immigration. The proposed method may be used to further estimate the prevalence by age, sex and residential status, which could potentially provide critical evidence towards establishing policies to control tuberculosis among foreign-born persons in Japan, and also possibly among migrants globally.

Factors influencing active tuberculosis case-finding policy development and implementation: a scoping review

OBJECTIVE

To explore antecedents, components and influencing factors on active case-finding (ACF) policy development and implementation.

DESIGN

Scoping review, searching MEDLINE, Web of Science, the Cochrane Database of Systematic Reviews and the World Health Organization (WHO) Library from January 1968 to January 2018. We excluded studies focusing on latent tuberculosis (TB) infection, passive case-finding, childhood TB and studies about effectiveness, yield, accuracy and impact without descriptions of how this evidence has/could influence ACF policy or implementation. We included any type of study written in English, and conducted frequency and thematic analyses.

RESULTS

Seventy-three articles fulfilled our eligibility criteria. Most (67%) were published after 2010. The studies were conducted in all WHO regions, but primarily in Africa (22%), Europe (23%) and the Western-Pacific region (12%). Forty-one percent of the studies were classified as quantitative, followed by reviews (22%) and qualitative studies (12%). Most articles focused on ACF for tuberculosis contacts (25%) or migrants (32%). Fourteen percent of the articles described community-based screening of high-risk populations. Fifty-nine percent of studies reported influencing factors for ACF implementation; mostly linked to the health system (eg, resources) and the community/individual (eg, social determinants of health). Only two articles highlighted factors influencing ACF policy development (eg, politics). Six articles described WHO's ACF-related recommendations as important antecedent for ACF. Key components of successful ACF implementation include health system capacity, mechanisms for integration, education and collaboration for ACF.

CONCLUSION

We identified some main themes regarding the antecedents, components and influencing factors for ACF policy development and implementation. While we know much about facilitators and barriers for ACF policy implementation, we know less about how to strengthen those facilitators and how to overcome those barriers. A major knowledge gap remains when it comes to understanding which contextual factors influence ACF policy development. Research is required to understand, inform and improve ACF policy development and implementation.

Seroprevalence and molecular characterization of Mycobacterium bovis infection in camels (Camelus dromedarius) in the Delta region, Egypt

AIM

This study aimed to determine the prevalence rates of Mycobacterium infection in camel sera collected before slaughter and gross lesion tissue collected postmortem (PM) using enzyme-linked immunosorbent assay (ELISA), bacteriological culture, and polymerase chain reaction (PCR). In addition, serum samples from humans who had occupational contact with camels were tested by ELISA and sputum sample by culture.

MATERIALS AND METHODS

ELISA was performed on serum samples antemortem. In addition, bacteriological culture and PCR were conducted after PM. Tuberculosis infection was identified in humans who had contact with camels using ELISA for serum samples and culture for sputum samples.

RESULTS

Tuberculous lesions were detected in 184 of 10,903 camels (1.7%). The ELISA results revealed that of the 184 examined camel serum samples, 124 (67.39%) were positive and all 20 camel serum samples that had no associated tuberculous lesions were negative. Moreover, only one of 48 (2.08%) human serum samples was positive by ELISA. Mycobacterial culture revealed 112 isolates from the 184 examined camel samples (60.87%), while human sputum sample cultures were all negative. PCR analysis identified the mpb70 gene in three of seven randomly tested samples.

CONCLUSION

Gene sequencing was performed on two samples and the sequences were submitted to the National Center for Biotechnology Information GenBank (accession numbers MF990289 and MG59479). A phylogenetic tree was constructed based on the partial DNA sequences of the mpb70 gene; the similarity between the isolates was 98.1%. The similarities between the two isolates and the standard strains of Mycobacterium bovis in GenBank were 98.1% and 100%, respectively. Further investigation on the antemortem detection of M. bovis infection in camels is needed to decrease public risk.

Tuberculosis screening for prospective migrants to high-income countries: systematic review of policies

OBJECTIVE

To compare predeparture tuberculosis (TB) screening policies, including screening criteria and screening tests, and visa requirements for prospective migrants to high-income countries that have low to intermediate TB incidence and high immigration.

STUDY DESIGN

Systematic review of policy documents.

METHODS

We systematically identified high-income, high net-migration countries with an estimated TB incidence of <30 per 100,000. After initial selection, this yielded 15 countries which potentially had TB screening policies. We performed a systematic search of governmental and official visa services' websites for these countries to identify visa information and policy documents for prospective migrants. Results were summarized, tabulated, and compared.

RESULTS

Programs to screen for active TB were identified in all 15 countries, but screening criteria and screening tests varied substantially between countries. Prospective migrants' country of origin represented an initial assessment criterion which generally focused on elevated TB incidence based on World Health Organization data but also focused on the countries of origin that sent the most migrants, and this varied between destination countries. Specific categories of migrants represented a second assessment criterion that focused on duration of stay and reasons for migration; the focus of which showed variation between the destination countries. Specific screening tests including medical examination and chest X-rays were used as the final stage of assessment, and there were differences between which tests were used between the destination countries.

CONCLUSIONS

Current approaches to migrant TB screening are inconsistent in their approach and implementation. While this variation might reflect adaptation to local public health situations, it could also indicate uncertainty concerning optimal strategies. Comparative research studies are needed to define the most effective and efficient methods for TB screening of migrants.

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.

Prevalence of tuberculosis infection and disease in children referred for tuberculosis medical surveillance in Ontario: a single-cohort study

BACKGROUND

There are few data about the utility of the Canadian tuberculosis medical surveillance system for detecting tuberculosis in children and adolescents. We sought to assess the prevalence of tuberculosis infection and disease in children and adolescents referred by the tuberculosis medical surveillance program who were evaluated at The Hospital for Sick Children (SickKids) tuberculosis program.

METHODS

We retrospectively studied clinical records, radiographic findings and results of interferon-γ release assays (IGRAs) of all children less than 18 years of age referred by the tuberculosis medical surveillance program and evaluated at SickKids between November 2012 and June 2016.

RESULTS

The median age of the 216 children was 10.0 years. Most were born in the Philippines (157 [72.7%]) or India (39 [18.0%]). Of the 216, 166 (76.8%) had a history of prior treatment for tuberculosis, and 34 (15.7%) were federal-sponsored refugees from settings with a high tuberculosis burden. Negative IGRA results were found in 110/130 (84.6%) of those with prior tuberculosis treatment. Thirty-one children (14.4%) had any chest radiographic abnormality, of whom 4 had changes thought to be due to tuberculosis. No child received a diagnosis of active tuberculosis at assessment or during follow-up; 3 (1.4%) were treated for latent tuberculosis infection following IGRA testing at SickKids. A positive IGRA result was associated with contact with infectious tuberculosis (odds ratio [OR] 5.97, 95% confidence interval [CI] 2.06-17.52) and older age at first clinic visit (OR 2.98, 95% CI 1.24-8.30) but not with radiographic abnormalities or history of prior tuberculosis treatment.

INTERPRETATION

Most children were referred because of a history of prior treatment for tuberculosis; few had clinical or laboratory evidence of infection or prior disease. The tuberculosis medical surveillance process did not identify any children who required treatment for active disease and requires improvement.

Migration and tuberculosis transmission in a middle-income country: a cross-sectional study in a central area of São Paulo, Brazil

BACKGROUND

Little is known about the impact of growing migration on the pattern of tuberculosis (TB) transmission in middle-income countries. We estimated TB recent transmission and its associated factors and investigated the presence of cross-transmission between South American migrants and Brazilians.

METHODS

We studied a convenient sample of cases of people with pulmonary TB in a central area of São Paulo, Brazil, diagnosed between 2013 and 2014. Cases with similar restriction fragment length polymorphism (IS6110-RFLP) patterns of their Mycobacterium tuberculosis complex isolates were grouped in clusters (recent transmission). Clusters with both Brazilian and South American migrants were considered mixed (cross-transmission). Risk factors for recent transmission were studied using logistic regression.

RESULTS

Isolates from 347 cases were included, 76.7% from Brazilians and 23.3% from South American migrants. Fifty clusters were identified, which included 43% South American migrants and 60.2% Brazilians (odds ratio = 0.50, 95% confidence interval = 0.30-0.83). Twelve cross-transmission clusters were identified, involving 24.6% of all clustered cases and 13.8% of all genotyped cases, with migrants accounting for either an equal part or fewer cases in 11/12 mixed clusters.

CONCLUSIONS

Our results suggest that TB disease following recent transmission is more common among Brazilians, especially among those belonging to high-risk groups, such as drug users. Cross-transmission between migrants and Brazilians was present, but we found limited contributions from migrants to Brazilians in central areas of São Paulo and vice versa.

Tuberculosis and immigration

Tuberculosis continues to be a major public health problem in Spain. The incidence of tuberculosis in the native population has declined steadily in recent years. Migration flows have changed drastically since the beginning of the 21st century, with Spain becoming a recipient country for immigrants. Because most of the immigrants comes from countries with high incidence of tuberculosis, the contribution of the migrant population to new cases of tuberculosis is higher in relative terms than its weight in the total population. Tuberculosis programs must address the cultural, economic and medical aspects of the disease, and particularly target groups at risk, including the migrant population. In this paper, we will review the epidemiology and dynamics of tuberculosis in the migrant population, their differentiating clinical characteristics and the programmatic actions to address the problem.

Prevalence rates of six selected infectious diseases among African migrants and refugees: a systematic review and meta-analysis

The objective of this paper was to systematically review the literature on the prevalence of selected infectious diseases among migrants/refugees of African origin and to provide policy makers and health care professionals with evidence-based information. We pursued a systematic review and meta-analysis to determine the prevalence of six selected infectious diseases (i.e., syphilis, helminthiasis, schistosomiasis, intestinal protozoa infections, hepatitis B, and hepatitis C) among migrants/refugees of African origin. Three electronic databases (i.e., PubMed, EMBASE, and ISI Web of Science) were searched without language restrictions. Relevant data were extracted and random-effects meta-analyses conducted. Only adjusted estimates were analyzed to help account for heterogeneity and potential confounding. We assessed the quality of evidence using the GRADE approach. The results were stratified by geographical region. Ninety-six studies were included. The evidence was of low quality due to the small numbers of countries, infectious diseases, and participants included. African migrants/refugees had median (with 95% confidence interval [95% CI]) prevalence for syphilis, helminthiasis, schistosomiasis, intestinal protozoa infection, hepatitis B, and hepatitis C of 6.0% [95% CI: 2.0-7.0%], 13.0% [95% CI: 9.5-14.5%], 14.0% [95% CI: 13.0-17.0%], 15.0% [95% CI: 10.5-21.0%], 10.0% [95% CI: 6.0-14.0%], and 3.0% [95% CI: 1.0-4.0%], respectively. We found high heterogeneity regardless of the disease (I ²; minimum 97.5%, maximum 99.7%). The relatively high prevalence of some infectious diseases among African migrants/refugees warrants for systematic screening. The large heterogeneity of the available published data does not allow for stratifying such screening programs according to the geographical origin of African migrants/refugees.

Capacity strengthening through pre-migration tuberculosis screening programmes: IRHWG experiences

Effective tuberculosis (TB) prevention and care for migrants requires population health-based approaches that treat the relationship between migration and health as a progressive, interactive process influenced by many variables and addressed as far upstream in the process as possible. By including capacity building in source countries, pre-migration medical screening has the potential to become an integral component of public health promotion, as well as infection and disease prevention, in migrant-receiving nations, while simultaneously increasing capabilities in countries of origin. This article describes the collaborative experiences of five countries (Australia, Canada, New Zealand, United Kingdom and the United States of America, members of the Immigration and Refugee Health Working Group [IRHWG]), with similar pre-migration screening programmes for TB that are mandated. Qualitative examples of capacity building through IRHWG programmes are provided. Combined, the IRHWG member countries screen approximately 2 million persons overseas every year. Large-scale pre-entry screening programmes undertaken by IRHWG countries require building additional capacity for health care providers, radiology facilities and laboratories. This has resulted in significant improvements in laboratory and treatment capacity, providing availability of these facilities for national public health programmes. As long as global health disparities and disease prevalence differentials exist, national public health programmes and policies in migrant-receiving nations will continue to be challenged to manage the diseases prevalent in these migrating populations. National TB programmes and regulatory systems alone will not be able to achieve TB elimination. The management of health issues resulting from population mobility will require integration of national and global health initiatives which, as demonstrated here, can be supported through the capacity-building endeavours of pre-migration screening programmes.

Migration to middle-income countries and tuberculosis-global policies for global economies

Background

International migration to middle-income countries is increasing and its health consequences, in particular increasing transmission rates of tuberculosis (TB), deserve consideration. Migration and TB are a matter of concern in high-income countries and targeted screening of migrants for active and latent TB infection is a main strategy to manage risk and minimize transmission. In this paper, we discuss some aspects of TB control and migration in the context of middle-income countries, together with the prospect of responding with equitable and comprehensive policies.

Main body

TB rates in middle-income countries remain disproportionally high among the poorest and most vulnerable groups in large cities where most migrant populations are concentrated. Policies that tackle migrant TB in high-income countries may be inadequate for middle-income countries because of their different socio-economic and cultural scenarios. Strategies to control TB in these settings must take into account the characteristics of middle-income countries and the complexity of TB as a disease of poverty. Intersectoral policies of social protection such as cash-transfer programs help reducing poverty and improving health in vulnerable populations. We address the development of new approaches to improve well-established strategies including contact tracing and active and latent TB screening as an ‘add on’ to the existing health care guidelines of conditional cash transfer programs. In addition, we discuss how it might improve health and welfare among both poor migrants and locally-born populations. Authorities from middle-income countries should recognise that migrants are a vulnerable social group and promote cooperation efforts between sending and receiving countries for mitigation of poverty and prevention of disease in this group.

Conclusions

Middle-income countries have long sent migrants overseas. However, the influx of large migrant populations into their societies is relatively new and a growing phenomenon and it is time to set comprehensive goals to improve health among these communities. Conditional cash transfer policies with TB screening and strengthening of DOTS are some strategies that deserve attention. Reduction of social and health inequality among migrants should be incorporated into concerted actions to meet TB control targets.

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.

Relation between BCG vaccine scar and an interferon-gamma release assay in immigrant children with "positive" tuberculin skin test (≥10 mm)

Background

Immigrants from countries with high incidence of tuberculosis (TB) are usually offered screening when they arrive to low incidence countries. The tuberculin skin test (TST) is often used. The interferon gamma release assays (IGRAs) are more specific and not affected by BCG vaccination. The aims of this study were 1. To see if there if there is a correlation between a positive IGRA (QFT) and presence of a BCG scar in children with TST ≥10 mm, 2. To compare the TST diameter with QFT result, 3. To see if chest X-ray can be omitted in QFT negative children despite TST ≥10 mm.

Methods

762 healthy children/adolescents (median age 14 years) arriving to Gothenburg and surroundings with TST ≥10 mm were tested with QFT.

Results

A total of 163/492 (33 %) children with BCG scar had positive QFT, whereas 205/270 (76 %) without BCG scar had positive QFT (p < 0.0001). The median TST was 12 mm in QFT negative and 18 mm in QFT positive children (p < 0.0001) but with considerable overlap. Median TST was the same (12 mm) in QFT negative children with and without BCG scar. Among the QFT positive children 25/368 had chest X-ray changes compared to 2/393 among the QFT negative children (p < 0.0007).

Conclusions

Previous BCG vaccination had an effect on the TST diameter so an IGRA is recommended to diagnose latent TB. Using only TST for screening of latent TB would lead to overdiagnosis. The TST diameter was larger in QFT positive than in QFT negative children but could not predict QFT in the individual patient. Chest X ray contributes little to the diagnosis of TB in QFT negative children but can not be omitted because of late seroconversion of QFT in some patients.

Trial registration

Not applicable.

Multidrug-resistant tuberculosis and migration to Europe

Multidrug-resistant tuberculosis (MDR-TB) in low-incidence countries in Europe is more prevalent among migrants than the native population. The impact of the recent increase in migration to EU and EEA countries with a low incidence of TB (<20 cases per 100 000) on MDR-TB epidemiology is unclear. This narrative review synthesizes evidence on MDR-TB and migration identified through an expert panel and database search. A significant proportion of MDR-TB cases in migrants result from reactivation of latent infection. Refugees and asylum seekers may have a heightened risk of MDR-TB infection and worse outcomes. Although concerns have been raised around 'health tourists' migrating for MDR-TB treatment, numbers are probably small and data are lacking. Migrants experience significant barriers to testing and treatment for MDR-TB, exacerbated by increasingly restrictive health systems. Screening for latent MDR-TB is highly problematic because current tests cannot distinguish drug-resistant latent infection, and evidence-based guidance for treatment of latent infection in contacts of MDR patients is lacking. Although there is evidence that transmission of TB from migrants to the general population is low-it predominantly occurs within migrant communities-there is a human rights obligation to improve the diagnosis, treatment and prevention of MDR-TB in migrants. Further research is needed into MDR-TB and migration, the impact of screening on detection or prevention, and the potential consequences of failing to treat and prevent MDR-TB among migrants in Europe. An evidence-base is urgently needed to inform guidelines for effective approaches for MDR-TB management in migrant populations in Europe.

Active Tuberculosis Case Finding Interventions Among Immigrants, Refugees and Asylum Seekers in Italy

In Italy tuberculosis (TB) is largely concentrated in vulnerable groups such as migrants and in urban settings. We analyzed three TB case finding interventions conducted at primary centers and mobile clinics for regular/irregular immigrants and refugees/asylum seekers performed over a four-year period (November 2009-March 2014) at five different sites in Rome and one site in Milan, Italy. TB history and presence of symptoms suggestive of active TB were investigated by verbal screening through a structured questionnaire in migrants presenting for any medical condition to out-patient and mobile clinics. Individuals reporting TB history or symptoms were referred to a TB clinic for diagnostic workup. Among 6347 migrants enrolled, 891 (14.0%) reported TB history or symptoms suggestive of active TB and 546 (61.3%) were referred to the TB clinic. Of them, 254 (46.5%) did not present for diagnostic evaluation. TB was diagnosed in 11 individuals representing 0.17% of those screened and 3.76% of those evaluated. The overall yield of this intervention was in the range reported for other TB screening programs for migrants, although we recorded an unsatisfactory adherence to diagnostic workup. Possible advantages of this intervention include low cost and reduced burden of medical procedures for the screened population.

Temporal Expression of Peripheral Blood Leukocyte Biomarkers in a Macaca fascicularis Infection Model of Tuberculosis; Comparison with Human Datasets and Analysis with Parametric/Non-parametric Tools for Improved Diagnostic Biomarker Identification

A temporal study of gene expression in peripheral blood leukocytes (PBLs) from a Mycobacterium tuberculosis primary, pulmonary challenge model Macaca fascicularis has been conducted. PBL samples were taken prior to challenge and at one, two, four and six weeks post-challenge and labelled, purified RNAs hybridised to Operon Human Genome AROS V4.0 slides. Data analyses revealed a large number of differentially regulated gene entities, which exhibited temporal profiles of expression across the time course study. Further data refinements identified groups of key markers showing group-specific expression patterns, with a substantial reprogramming event evident at the four to six week interval. Selected statistically-significant gene entities from this study and other immune and apoptotic markers were validated using qPCR, which confirmed many of the results obtained using microarray hybridisation. These showed evidence of a step-change in gene expression from an ‘early’ FOS-associated response, to a ‘late’ predominantly type I interferon-driven response, with coincident reduction of expression of other markers. Loss of T-cell-associate marker expression was observed in responsive animals, with concordant elevation of markers which may be associated with a myeloid suppressor cell phenotype e.g. CD163. The animals in the study were of different lineages and these Chinese and Mauritian cynomolgous macaque lines showed clear evidence of differing susceptibilities to Tuberculosis challenge. We determined a number of key differences in response profiles between the groups, particularly in expression of T-cell and apoptotic makers, amongst others. These have provided interesting insights into innate susceptibility related to different host `phenotypes. Using a combination of parametric and non-parametric artificial neural network analyses we have identified key genes and regulatory pathways which may be important in early and adaptive responses to TB. Using comparisons between data outputs of each analytical pipeline and comparisons with previously published Human TB datasets, we have delineated a subset of gene entities which may be of use for biomarker diagnostic test development.

The impact of migration on tuberculosis epidemiology and control in high-income countries: a review

Tuberculosis (TB) causes significant morbidity and mortality in high-income countries with foreign-born individuals bearing a disproportionate burden of the overall TB case burden in these countries. In this review of tuberculosis and migration we discuss the impact of migration on the epidemiology of TB in low burden countries, describe the various screening strategies to address this issue, review the yield and cost-effectiveness of these programs and describe the gaps in knowledge as well as possible future solutions.The reasons for the TB burden in the migrant population are likely to be the reactivation of remotely-acquired latent tuberculosis infection (LTBI) following migration from low/intermediate-income high TB burden settings to high-income, low TB burden countries.TB control in high-income countries has historically focused on the early identification and treatment of active TB with accompanying contact-tracing. In the face of the TB case-load in migrant populations, however, there is ongoing discussion about how best to identify TB in migrant populations. In general, countries have generally focused on two methods: identification of active TB (either at/post-arrival or increasingly pre-arrival in countries of origin) and secondly, conditionally supported by WHO guidance, through identifying LTBI in migrants from high TB burden countries. Although health-economic analyses have shown that TB control in high income settings would benefit from providing targeted LTBI screening and treatment to certain migrants from high TB burden countries, implementation issues and barriers such as sub-optimal treatment completion will need to be addressed to ensure program efficacy.

A systematic review on TST and IGRA tests used for diagnosis of LTBI in immigrants

BACKGROUND

High immigration rates from tuberculosis (TB) endemic countries to low-incidence countries have caused new TB guidelines in these countries to reconsider latent TB infection (LTBI) screening in these immigrants.

OBJECTIVES

We performed a systematic review with the primary outcome of evaluating the number of cases recommended LTBI treatment with the tuberculin skin test (TST) or interferon gamma release assay (IGRA). Secondary objectives were to examine prevalence of positive LTBI diagnostic tests stratified by age and incidence of TB in country of origin.

METHODS

We performed a systematic search of seven electronic databases for studies assessing TST and/or IGRA performance in immigrant populations to low incidence countries. Demographics, LTBI diagnosis, longitudinal TB development, and test result data were the primary data extracted from the studies. Prevalence of positive test data was stratified by age and country of origin. Studies were evaluated using a modified SIGN checklist for diagnostic studies. Data was compared using Fisher's exact test or χ (2) test, where appropriate.

RESULTS

Our literature search yielded 51 studies (n = 34 TST, n = 9 IGRA, n = 8 both). Recommendation of LTBI treatment was less common in those tested with an IGRA compared to TST (p < 0.0001), while long-term development of active TB appears higher in those with a positive IGRA. There was no difference in the sensitivity and specificity of the IGRA and TST for prevalent TB (p > 0.05). Prevalence of a positive test was significantly lower in those who were <18 years of age compared to those ≥18 years of age (p < 0.0001) and those from low TB incidence countries compared to high incidence countries (p < 0.0001) for both TST and IGRA. When comparing the two tests within the 2 subgroups: age and TB incidence in country of origin, the prevalence of positive results was significantly lower for the IGRA than the TST (p < 0.0001).

LIMITATIONS

The number of available studies evaluating the IGRA and longitudinal active TB development in those tested limits this study.

CONCLUSION

Prevalence of positive test results were significantly lower in immigrants who were tested with an IGRA, resulting in fewer immigrants being recommended for LTBI treatment compared to TST. Coupled with comparable performance for detecting prevalent TB cases, the IGRA appears to exhibit better specificity than the TST and may be preferred as the standard of care for detecting LTBI in immigrants moving to low TB incidence countries.

Domestic impact of tuberculosis screening among new immigrants to Ontario, Canada

BACKGROUND

All Canadian immigrants undergo screening for tuberculosis (TB) before immigration, and selected immigrants must undergo postimmigration surveillance for the disease. We sought to quantify the domestic health impact of screening for TB in all new immigrants and to identify mechanisms to enhance effectiveness and efficiency of this screening.

METHODS

We linked preimmigration medical examination records from 944,375 immigrants who settled in Ontario between 2002 and 2011 to active TB reporting data in Ontario between 2002 and 2011. Using a retrospective cohort study design, we measured birth country-specific rates of active TB detected through preimmigration screening and postimmigration surveillance. We then quantified the proportion of active TB cases among residents of Ontario born abroad that were detected through postimmigration surveillance. Using Cox regression, we identified independent predictors of active TB postimmigration.

RESULTS

Immigrants from 6 countries accounted for 87.3% of active TB cases detected through preimmigration screening, and 10 countries accounted for 80.4% of cases detected through postimmigration surveillance. Immigrants from countries with a TB (all-sites) incidence rate of less than 30 cases per 100 000 persons resulted in pre- and postimmigration detection of 2.4 and 0.9 cases per 100 000 immigrants, respectively. Postimmigration surveillance detected 2.6% of active TB cases in Ontario residents born abroad, and TB was detected a median of 18 days earlier in those undergoing surveillance than in those who were not referred to surveillance or who did not comply. Predictors of active TB postimmigration included radiographic markers of old TB, birth country, immigration category, location of application for residency, immune status and age.

INTERPRETATION

Universal screening for TB in new immigrants has a modest impact on the domestic burden of active TB and is highly inefficient. Focusing preimmigration screening in countries with high incidence rates and revising criteria for postimmigration surveillance could increase the effectiveness and efficiency of screening.

A scoping review of cost-effectiveness of screening and treatment for latent tubercolosis infection in migrants from high-incidence countries

Background

In low-incidence countries, most tuberculosis (TB) cases occur among migrants and are caused by reactivation of latent tuberculosis infection (LTBI) acquired in the country of origin. Diagnosis and treatment of LTBI are rarely implemented to reduce the burden of TB in immigrants, partly because the cost-effectiveness profile of this intervention is uncertain.

The objective of this research is to perform a review of the literature to assess the cost-effectiveness of LTBI diagnosis and treatment strategies in migrants.

Methods

Scoping review of economic evaluations on LTBI screening strategies for migrants was carried out in Medline.

Results

Nine studies met the inclusion criteria. LTBI screening was cost-effective according to seven studies. Findings of four studies support interferon gamma release assay as the most cost-effective test for LTBI screening in migrants. Two studies found that LTBI screening is cost-effective only if carried out in immigrants who are contacts of active TB cases.

Discussion and Conclusions

Our findings support the cost-effectiveness of LTBI diagnostic and treatment strategies in migrants especially if they are focused on young subjects from high incidence countries. These strategies could represent and adjunctive and synergistic tool to achieve the ambitious aim of TB elimination.

Electronic supplementary material

The online version of this article (doi:10.1186/s12913-015-1045-3) contains supplementary material, which is available to authorized users.

Cost-Effectiveness of Screening and Treating Foreign-Born Students for Tuberculosis before Entering the United States

Introduction

The Centers for Disease Control and Prevention is considering implementation of overseas medical screening of student-visa applicants to reduce the numbers of active tuberculosis cases entering the United States.

Objective

To evaluate the costs, cases averted, and cost-effectiveness of screening for, and treating, tuberculosis in United States-bound students from countries with varying tuberculosis prevalence.

Methods

Costs and benefits were evaluated from two perspectives, combined and United States only. The combined perspective totaled overseas and United States costs and benefits from a societal perspective. The United States only perspective was a domestic measure of costs and benefits. A decision tree was developed to determine the cost-effectiveness of tuberculosis screening and treatment from the combined perspective.

Results

From the United States only perspective, overseas screening programs of Chinese and Indian students would prevent the importation of 157 tuberculosis cases annually, and result in $2.7 million in savings. From the combined perspective, screening programs for Chinese students would cost more than $2.8 million annually and screening programs for Indian students nearly $440,000 annually. From the combined perspective, the incremental cost for each tuberculosis case averted by screening Chinese and Indian students was $22,187 and $15,063, respectively. Implementing screening programs for German students would prevent no cases in most years, and would result in increased costs both overseas and in the United States. The domestic costs would occur because public health departments would need to follow up on students identified overseas as having an elevated risk of tuberculosis.

Conclusions

Tuberculosis screening and treatment programs for students seeking long term visas to attend United States schools would reduce the number of tuberculosis cases imported. Implementing screening in high-incidence countries could save the United States millions of dollars annually; however there would be increased costs incurred overseas for students and their families.

USA's expanded overseas tuberculosis screening program: a retrospective study in China

BACKGROUND

To address increasing tuberculosis (TB) incidence in foreign-born populations, immigrant TB screening programs have been implemented in the USA. These programs are modified periodically, the effectiveness of which have been disputed. The aim of this retrospective study was to assess the value of the 2009 Technical Instructions for Tuberculosis Screening and Treatment Using Cultures and Directly Observed Therapy (CDOT TB TI) in a cohort of the USA permanent-resident applicants from China.

METHODS

Standardized forms were used to collect demographic, clinical, and laboratory data of Chinese individuals screened at the Guangdong International Travel Healthcare Center for permanent residence in the USA between October 08, 2009 and December 31, 2012. Applicants' data were further retrospectively evaluated by three experienced panel physicians and radiologists according to the 1991 Technical Instructions for Tuberculosis Screening and Treatment (TI). TB cases and characteristics identified by the 1991 and expanded 2009 programs were compared.

RESULTS

The CDOT TB TI identified more than twice as many TB cases that required treatment completion before clearance for travel than the 1991 TI (270 vs. 131). In addition, the expanded screening program identified more cases of negative sputum smear but positive culture (181 vs. 44), and more cases of radiography suggestive of inactive (22 vs. 3) and active (248 vs. 128) TB. Specifically, the 1991 TI screening program failed to identify 25/38 (65.79%) cases carrying drug-resistant isolates, and 13/131 (9.92%) would have been inappropriately treated. Moreover, 220/270 (81.48%) of the cases were asymptomatic, which were identified by screening and subsequently treated. Improved chest radiograph and sputum negative conversion occurred in all treated cases.

CONCLUSION

CDOT TB TI, a screening program that includes sputum culture and drug susceptibility tests, identifies a greater number of TB cases, likely contributing to the overall decrease in TB prevalence in host (USA) and origin (China) countries.

Strengthening tuberculosis control overseas: who benefits?

BACKGROUND

Although tuberculosis is a major cause of morbidity and mortality worldwide, available funding falls far short of that required for effective control. Economic and spillover consequences of investments in the treatment of tuberculosis are unclear, particularly when steep gradients in the disease and response are linked by population movements, such as that between Papua New Guinea (PNG) and the Australian cross-border region.

OBJECTIVE

To undertake an economic evaluation of Australian support for the expansion of basic Directly Observed Treatment, Short Course in the PNG border area of the South Fly from the current level of 14% coverage.

METHODS

Both cost-utility analysis and cost-benefit analysis were applied to models that allow for population movement across regions with different characteristics of tuberculosis burden, transmission, and access to treatment. Cost-benefit data were drawn primarily from estimates published by the World Health Organization, and disease transmission data were drawn from a previously published model.

RESULTS

Investing $16 million to increase basic Directly Observed Treatment, Short Course coverage in the South Fly generates a net present value of roughly $74 million for Australia (discounted 2005 dollars). The cost per disability-adjusted life-year averted and quality-adjusted life-year saved for PNG is $7 and $4.6, respectively.

CONCLUSIONS

Where regions with major disparities in tuberculosis burden and health system resourcing are connected through population movements, investments in tuberculosis control are of mutual benefit, resulting in net health and economic gains on both sides of the border. These findings are likely to inform the case for appropriate investment in tuberculosis control globally.

Imported transmissible diseases in minors coming to Spain from low-income areas

We prospectively studied the prevalence of imported transmissible diseases in 373 immigrant children and adolescents coming from Sub-Saharan Africa, North Africa and Latin America to Salamanca, Spain. The most frequent transmissible diseases in this group were latent tuberculosis (12.7%), chronic hepatitis B virus infection (4.2%), hepatitis C virus infection (2.3%), syphilis (1.5%) and human T-lymphotropic virus type 1 or 2 infections (1.4%). A total of 24.2% of patients had serologic profiles suggesting past hepatitis B virus infection. Anti-human immunodeficiency virus antibodies were not detected in any subject. Largely asymptomatic immigrant children show a high prevalence of communicable diseases. Thus, infectious disease screenings are highly advisable in immigrant children coming from low-income countries.

Can migration health assessments become a mechanism for global public health good?

Migrant health assessments (HAs) consist of a medical examination to assess a migrant’s health status and to provide medical clearance for work or residency based on conditions defined by the destination country and/or employer. We argue that better linkages between health systems and migrant HA processors at the country level are needed to shift these from being limited as an instrument of determining non-admissibility for purposes of visa issuance, to a process that may enhance public health. The importance of providing appropriate care and follow-up of migrants who “fail” their HA and the need for global efforts to enable data-collection and research on HAs are also highlighted.

Collaboration between municipal and specialist public health care in tuberculosis screening in Norway

Background

About 90% of new tuberculosis (TB) cases in Norway appear among immigrants from high incidence countries. There is a compulsory governmental tuberculosis screening programme for immigrants; immigrants with positive screening results are to be referred from municipal health care to the specialist health care for follow-up. Recent studies of the screening programme have shown inadequate follow-up. One of the main problems has been that patients referred for follow-up have not attended their appointment at the specialist health care.

TB screening in the municipality of Trondheim is done by two different teams: the Refugee Healthcare Centre (RHC) screens refugees and the Vaccination and Infection Control Office (VICO) screens all the other groups. Patients with positive findings on screening are referred to the hospital’s Pulmonary Out-patient Department (POPD). The municipal and referral level public health care initiated a project aiming to improve follow-up through closer collaboration.

Methods

An intervention group and a pre-intervention control group were established for each screening group. During meetings between staff from the municipality and the POPD, inadequacies in the screening process were identified, and changes in procedures for summoning patients, and time and place for tests were implemented. For both the intervention group and the control group, time from referral until consultation at the POPD and number of patients that attended their first appointment were registered and compared.

Results

In the VICO group, 97/134 (72%) of the controls and 109/123 (89%) of the intervention group attended their first appointment at the POPD after 30 weeks (median) and 10 weeks, respectively. In the RHC group 28/46 (61%) of the controls and 55/59 (93%) in the intervention group attended their first appointment after 15 and 8 weeks (median) respectively.

Conclusion

Increased collaboration between the municipal and specialist health care can improve the follow-up of positive TB screening results.

HIV-exposed uninfected children: a growing population with a vulnerable immune system?

Through the successful implementation of policies to prevent mother-to-child-transmission (PMTCT) of HIV-1 infection, children born to HIV-1-infected mothers are now much less likely to acquire HIV-1 infection than previously. Nevertheless, HIV-1-exposed uninfected (HEU) children have substantially increased morbidity and mortality compared with children born to uninfected mothers (unexposed uninfected, UU), predominantly from infectious causes. Moreover, a range of phenotypical and functional immunological differences between HEU and UU children has been reported. As the number of HEU children continues to increase worldwide, two questions with clear public health importance need to be addressed: first, does exposure to HIV-1 and/or ART in utero or during infancy have direct immunological consequences, or are these poor outcomes simply attributable to the obvious disadvantages of being born into an HIV-affected household? Secondly, can we expect improved maternal care and ART regimens during and after pregnancy, together with optimized infant immunization schedules, to reduce the excess morbidity and mortality of HEU children?

Tuberculosis screening in immigrants from high-prevalence countries: interview first or chest radiograph first? A pro/con debate

Immigration from high tuberculosis (TB) prevalence countries has a substantial impact on the epidemiology of TB in receiving countries with low TB incidence. Cross-border migration offers an ideal opportunity for active case finding that will result in a lower caseload in the host country and a reduced spread of disease to both the indigenous and migrant populations. Screening strategies can start 'offshore', thereby indirectly assisting and empowering public health systems in the source countries, or be performed at ports of entry with or without long-term engagement of 'onshore' facilities and systems to provide either preventive therapy or surveillance for reactivation of latent TB. The chest radiograph seems to be playing a key role in this process, but questions remain regarding when, where and in whom radiographs are best done for optimal yield and cost-effectiveness, and with what other tests they might best be combined to further increase the usefulness of transborder TB control.

Tuberculosis case finding based on symptom screening among immigrants, refugees and asylum seekers in Rome

Background

In Italy the proportion of cases of tuberculosis in persons originating from high-prevalence countries has been increasing in the last decade. We designed a study to assess adherence to and yield of a tuberculosis screening programme based on symptom screening conducted at primary care centres for regular and irregular immigrants and refugees/asylum seekers.

Methods

Presence of symptoms suggestive of active tuberculosis was investigated by verbal screening in migrants presenting for any medical condition to 3 free primary care centres in the province of Rome. Individuals reporting at least one symptom were referred to a tuberculosis clinic for diagnostic workup.

Results

Among 2142 migrants enrolled, 254 (11.9%) reported at least one symptom suggestive of active tuberculosis and 176 were referred to the tuberculosis clinic. Of them, 80 (45.4%) did not present for diagnostic evaluation. Tuberculosis was diagnosed in 7 individuals representing 0.33% of those screened and 7.3% of those evaluated for tuberculosis.

Conclusion

The overall yield of this intervention was in the range reported for other tuberculosis screening programmes for migrants, although we recorded an unsatisfactory adherence to diagnostic workup. Possible advantages of this intervention include low cost and reduced burden of medical procedures for the screened population. Further evaluation of this approach appears to be warranted.

Educating international students about tuberculosis and infections associated with travel to visit friends and relatives (VFR-travel)

BACKGROUND

International students in Victoria, Australia, originate from over 140 different countries. They are over-represented in disease notifications for tuberculosis and travel-associated infections, including enteric fever, hepatitis A, and malaria. We describe a public health initiative aimed to increase awareness of these illnesses among international students and their support staff.

METHODS

We identified key agencies including student support advisors, medical practitioners, health insurers, and government and professional organisations. We developed health education materials targeting international students regarding tuberculosis and travel-related infections to be disseminated via a number of different media, including electronic and printed materials. We sought informal feedback from personnel in all interested agencies regarding the materials developed, their willingness to deliver these materials to international students, and their preferred media for disseminating these materials.

RESULTS

Education institutions with dedicated international student support staff and on-campus health clinics were more easily engaged to provide feedback and disseminate the health education materials than institutions without such dedicated personnel. Response to contacting off-campus medical practices was poor. Delivery of educational materials via electronic and social media was preferred over face-to-face education.

CONCLUSIONS

It is feasible to provide health education messages targeting international students for dissemination via appropriately-staffed educational institutions. This initiative could be expanded in terms of age-group, geographic range, and health issues to be targeted.

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.

Evaluation of immigrant tuberculosis screening in industrialized countries

Improvements are needed in current screening, which is insufficient and ineffective.

In industrialized countries, tuberculosis (TB) cases are concentrated among immigrants and driven by reactivation of imported latent TB infection (LTBI). We examined mechanisms used to screen immigrants for TB and LTBI by sending an anonymous, 18-point questionnaire to 31 member countries of the Organisation for Economic Co-operation and Development. Twenty-nine (93.5%) of 31 responded; 25 (86.2%) screened immigrants for active TB. Fewer countries (16/29, 55.2%) screened for LTBI. Marked variations were observed in targeted populations for age (range <5 years of age to all age groups) and TB incidence in countries of origin of immigrants (>20 cases/100,000 population to >500 cases/100,000). LTBI screening was conducted in 11/16 countries by using the tuberculin skin test. Six countries used interferon-γ release assays, primarily to confirm positive tuberculin skin test results. Industrialized countries performed LTBI screening infrequently and policies varied widely. There is an urgent need to define the cost-effectiveness of LTBI screening strategies for immigrants.

Spectrum of illness in international migrants seen at GeoSentinel clinics in 1997-2009, part 1: US-bound migrants evaluated by comprehensive protocol-based health assessment

BACKGROUND

Many nations are struggling to develop structured systems and guidelines to optimize the health of new arrivals, but there is currently no international consensus about the best approach.

METHODS

Data on 7792 migrants who crossed international borders for the purpose of resettlement and underwent a protocol-based health assessment were collected from the GeoSentinel Surveillance network. Demographic and health characteristics of a subgroup of these migrants seen at 2 US-based GeoSentinel clinics for protocol-based health assessments are described.

RESULTS

There was significant variation over time in screened migrant populations and in their demographic characteristics. Significant diagnoses identified in all migrant groups included latent tuberculosis, found in 43% of migrants, eosinophilia in 15%, and hepatitis B infection in 6%. Variation by region occurred for select diagnoses such as parasitic infections. Notably absent were infectious tuberculosis, soil-transmitted helminths, and malaria. Although some conditions would be unfamiliar to clinicians in receiving countries, universal health problems such as dental caries, anemia, ophthalmologic conditions, and hypertension were found in 32%, 11%, 10%, and 5%, respectively, of screened migrants.

CONCLUSIONS

Data from postarrival health assessments can inform clinicians about screening tests to perform in new immigrants and help communities prepare for health problems expected in specific migrant populations. These data support recommendations developed in some countries to screen all newly arriving migrants for some specific diseases (such as tuberculosis) and can be used to help in the process of developing additional screening recommendations that might be applied broadly or focused on specific at-risk populations.

Incidence rates and deaths of tuberculosis in HIV-negative patients in the United States and Germany as analyzed by new predictive model for infection

Incidence and mortality due to tuberculosis (TB) have been decreasing worldwide. Given that TB is a cosmopolitan disease, proper surveillance and evaluation are critical for controlling dissemination. Herein, mathematical modeling was performed in order to: 1) demonstrate a correlation between the incidence of TB in HIV-free patients in the US and Germany, and their corresponding mortality rates; 2) show the utility of the newly developed D-R algorithm for analyzing and predicting the incidence of TB in both countries; and 3) inform us on population death rates due to TB in HIV-negative patients. Using data published by the World Health Organization between 1990 and 2009, the relationship between incidence and mortality that could not be ascribed to HIV infection was evaluated. Using linear, quadratic and cubic curves, we found that a cubic function provided the best fit with the data in both the US (Y = 2.3588+2.2459X+61.1639X²−60.104X³) and Germany (Y = 1.9271+9.4967X+18.3824X²−10.350X³) where the correlation coefficient (R) between incidence and mortality was 0.995 and 0.993, respectively. Second, we demonstrated that fitted curves using the D-R model were equal to or better than those generated using the GM(1,1) algorithm as exemplified in the relative values for Sum of Squares of Error, Relative Standard Error, Mean Absolute Deviation, Average Relative Error, and Mean Absolute Percentage Error. Finally, future trends using both the D-R and the classic GM(1,1) models predicted a continued decline in infection and mortality rates of TB in HIV-negative patients rates extending to 2015 assuming no changes to diagnosis or treatment regimens are enacted.