Tuberculosis transmission between foreign- and native-born populations in the EU/EEA: a systematic review

Climate change and tuberculosis: an analytical framework

Climate change is likely to exacerbate a range of determinants which drive tuberculosis, the world's leading infectious disease killer. However, tuberculosis is often neglected in wider climate health discussions. Commissioned by the World Health Organization, we developed an analytical framework outlining potential causal relationships between climate change and tuberculosis. We drew on existing knowledge of tuberculosis determinants, identified which are likely to be sensitive to the effects of climate change, and conceptualised the mechanistic pathways through which this might occur. We collated evidence for these pathways through literature reviews. Our reviews found no studies directly linking climate change and tuberculosis, warranting research to build evidence for action. The available evidence supports the existence of plausible links between climate change and tuberculosis, and highlights the need to include tuberculosis in climate risk adaptation and mitigation programmes, and climate-resilient funding and response mechanisms. Further evidence is urgently needed to quantify the effects of climate change on tuberculosis.

Implications for TB control among migrants in large cities in China: a prospective population-based genomic epidemiology study in Shenzhen

Internal migrants are a challenge for TB control in large Chinese cities and understanding this epidemiology is crucial for designing effective control and prevention strategies. We conducted a prospective genomic epidemiological study of culture-positive TB patients diagnosed between June 1, 2018 and May 31, 2021 in the Longhua District of Shenzhen. Treatment status was obtained from local and national TB registries and all isolates were sequenced. Genomic clusters were defined as strains differing by ≤12 SNPs. Risk factors for clustering were identified with multivariable analysis and then Bayesian models and TransPhylo were used to infer the timing of transmission within clusters. Of the 2277 culture-positive patients, 70.1% (1596/2277) were migrants: 72.1% (1043/1446) of the migrants patients developed TB within two years of arriving in Longhua; 38.8% within 6 months of arriving; and 12.3% (104/843) had TB symptoms when they arrived. Only 15.4% of Longhua strains were in genomic clusters. More than one third (33.6%) of patients were not treated in Shenzhen but were involved in nearly one third of the recent transmission events. Clustering was associated with migrants not treated in Shenzhen, males, and teachers/trainers. TB in Longhua is prinicipally due to reactivation of infections in migrants, but a proportion may have had clinical or incipient TB upon arrival in the district. Patients diagnosed but not treated in Longhua were involved in recent local TB transmission. Controlling TB in Shenzhen will require strategies to comprehensively diagnose and treat active TB in the internal migrant population.

[Emergence of a multidrug-resistant tuberculosis through inadequate treatment of isoniazid monoresistance]

HISTORY

 We admitted a 65-year-old patient with suspected reactivation of a pulmonary tuberculosis for further diagnosis.

FINDINGS AND DIAGNOSIS

 14 months after completing a standard treatment course against pulmonary tuberculosis, the patient presented with cough and night sweat. A CT-scan revealed signs of a bipulmonary progress. Microbiological results proved multi-drug resistant tuberculosis (resistances against isoniazid and rifampicin). Reviewing the patient's old records uncovered a previous isoniazid-resistance at the start of the first treatment course, which had not been appropriately addressed.

THERAPY AND COURSE

 The patient was started on oral therapy with Bedaquiline, Linezolid, Terizidon and Levofloxacin.

CONCLUSION

 Treating tuberculosis, considering drug resistances is crucial. To avoid ineffective therapy, molecular diagnostic methods are recommended, however, cultural testing remains essential. Diagnostic latency, rising rates of drug resistances and lengthy treatment courses contribute to the complexity of treatment. In Germany, specialized outpatient clinics are available since 2014 for diagnosis and treatment of patients with tuberculosis or non-tuberculous mycobacterial diseases, even in the event of mere suspicion.

Health inequalities in infectious diseases: a systematic overview of reviews

OBJECTIVES

The aim of this systematic overview of reviews was to synthesise available evidence on inequalities in infectious disease based on three dimensions of inequalities; inclusion health groups, protected characteristics and socioeconomic inequalities.

METHODS

We searched MEDLINE, Embase, Web of Science and OpenGrey databases in November 2021. We included reviews published from the year 2000 which examined inequalities in the incidence, prevalence or consequences of infectious diseases based on the dimensions of interest. Our search focused on tuberculosis, HIV, sexually transmitted infections, hepatitis C, vaccination and antimicrobial resistance. However, we also included eligible reviews of any other infectious diseases. We appraised the quality of reviews using the Assessment of Multiple Systematic Reviews V.2 (AMSTAR2) checklist. We conducted a narrative data synthesis.

RESULTS

We included 108 reviews in our synthesis covering all the dimensions of inequalities for most of the infectious disease topics of interest, however the quality and volume of review evidence and consistency of their findings varied. The existing literature reviews provide strong evidence that people in inclusion health groups and lower socioeconomic status are consistently at higher risk of infectious diseases, antimicrobial resistance and incomplete/delayed vaccination. In the protected characteristics dimension, ethnicity, and sexual orientation are important factors contributing to inequalities across the various infectious disease topics included in this overview of reviews.

CONCLUSION

We identified many reviews that provide evidence of various types of health inequalities in different infectious diseases, vaccination, and antimicrobial resistance. We also highlight areas where reviews may be lacking. The commonalities in the associations and their directions suggest it might be worth targeting interventions for some high risk-groups that may have benefits across multiple infectious disease outcomes rather than operating purely in infectious disease siloes.

Tuberculosis in the Head and Neck: Changing Trends and Age-Related Patterns

OBJECTIVE

To evaluate changing trends in patient collectives, age-related patterns of manifestation, and diagnostic pathways of patients with extrapulmonary head and neck tuberculosis (TB), and to provide strategies to fasten diagnosis in these patients.

STUDY DESIGN

Case control study.

METHODS

A 10-year retrospective analysis of 35 patients diagnosed with extrapulmonary TB in the head and neck at a tertiary university institution from 2009 to 2019, with special focus on the influence of the patient's age on consideration of TB and clinical patterns.

RESULTS

The vast majority of patients younger than 40 years had their origin in countries with high TB burden (P = .0003), and TB was considered very early as a differential diagnosis (P = .0068), while most patients older than 40 years were domestic citizens initially suspected for a malignancy, who more often had an underlying immunosuppressive condition (0.0472). Most frequent manifestations in both groups were the lymph nodes, larynx, and oropharynx. Surprisingly, no differences in the rates of open TB or history of TB infection in the family anamnesis were found.

CONCLUSION

The two groups of patients found most often are younger patients migrating from regions with high TB burden and elderly domestic patients suffering from immunosuppressive conditions, with the latter often being misdiagnosed as malignancies. TB remains an important but difficult differential diagnosis, due to the initially unspecific symptoms and the great variety in the presentation of manifestations in the head and neck.

LEVEL OF EVIDENCE

4 "case-control study" Laryngoscope, 2021.

Transmission of tuberculosis between foreign-born and Finnish-born populations in Finland, 2014-2017

We describe the epidemiology of tuberculosis (TB) and characterized Mycobacterium tuberculosis (M. tuberculosis) isolates to evaluate transmission between foreign-born and Finnish-born populations. Data on TB cases were obtained from the National Infectious Disease Register and denominator data on legal residents and their country of birth from the Population Information System. M. tuberculosis isolates were genotyped by spoligotyping and Mycobacterial Interspersed Repetitive Unit Variable Number Tandem Repeat (MIRU-VNTR). We characterized clusters by age, sex, origin and region of living which included both foreign-born cases and those born in Finland. During 2014-2017, 1015 TB cases were notified; 814 were confirmed by culture. The proportion of foreign-born cases increased from 33.3% to 39.0%. Foreign-born TB cases were younger (median age, 28 vs. 75 years), and had extrapulmonary TB or multidrug-TB more often than Finnish-born cases (P<0.01 for all comparisons). Foreign-born cases were born in 60 different countries; most commonly in Somalia (25.5%). Altogether 795 isolates were genotyped; 31.2% belonged to 80 different clusters (range, 2-13 cases/cluster). Fourteen (17.5%) clusters included isolates from both Finnish-born and foreign-born cases. An epidemiological link between cases was identified by (epidemiological) background information in two clusters. Although the proportion of foreign-born TB cases was considerable, our data suggests that transmission of TB between foreign and Finnish born population is uncommon.

"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.

Cost-effectiveness of targeted screening for active pulmonary tuberculosis among asylum-seekers: A modelling study with screening data from a German federal state (2002-2015)

Screening asylum-seekers for active pulmonary tuberculosis is common practice among many European countries with low incidence of tuberculosis. The reported yields vary substantially, partly due to the heterogeneous and dynamic nature of asylum-seeking populations. Rather than screening all new arrivals (indiscriminate screening), a few countries apply targeted screening based on incidence of tuberculosis in asylum-seekers' country of origin. However, evaluations of its cost-effectiveness have been scarce. The aim of this modelling study was to assess whether the introduction of a screening threshold based on the tuberculosis incidence in the country of origin is sensible from an economic perspective. To this end, we compare the current, indiscriminate screening policy for pulmonary tuberculosis in Germany with a hypothetical targeted screening programme using several potential screening thresholds based on WHO-reported incidence of tuberculosis in countries of origin. Screening data is taken from a large German federal state over 14 years (2002-2015). Incremental cost-effectiveness is measured as cost per case found and cost per case prevented. Our analysis shows that incremental cost-effectiveness ratios (ICERs) of screening asylum-seekers from countries with an incidence of 50 to 250/100,000 range between 15,000€ and 17,000€ per additional case found when compared to lower thresholds. The ICER for screening asylum-seekers from countries with an incidence <50/100,000 is 112,000€ per additional case found. Costs per case prevented show a similar increase in costs. The high cost per case found and per case prevented at the <50/100,000 threshold scenario suggests this threshold to be a sensible cut-off for targeted screening. Acknowledging that no screening measure can find all cases of tuberculosis, and that reactivation of latent infections makes up a large proportion of foreign-born cases, targeting asylum-seekers from countries with an incidence above 50/100,000 is likely to be a more reasonable screening measure for the prevention and control of tuberculosis than indiscriminate screening measures.

Health conditions of migrants landed in north-eastern Sicily and perception of health risks of the resident population

OBJECTIVES

In Italy, a recent irregular movement of people raised concerns among the host population on possible introduction of diseases that have long been controlled in the host countries. This study evaluates the health conditions of illegal immigrants landed on the north-eastern Sicilian territory, to provide information on the clinical and epidemiologic burden of infectious diseases among migrants and how the local population feel about these landings.

STUDY DESIGN

The study design is a cross-sectional study.

METHODS

The study considered all migrants landed illegally in the city of Messina, Sicily, between January 2014 and July 2018. Analysing the data of hospital admissions and disease notifications, we calculated the frequency of infectious diseases among migrant population. Furthermore, through a survey conducted by a well-known online newspaper, we analysed the perception that the local population has about the health risk represented by migrants.

RESULTS

In the considered five-year period, 108 landings, for a total of 38,608 migrants occurred at the Messina port. The percentage of hospitalisation was rather low (3.5%), and it concerned mainly pregnant women. The notifications of infectious diseases were contained, with exception of scabies and tuberculosis. Finally, from the online survey, resulted that there is a large part of local population that considers migrants a potential danger to community health.

CONCLUSIONS

Our data show that the presence of migrants should not have to date any impact on the health conditions of the resident population. However, monitoring over time the health of migrants and screening for infectious diseases as soon as possible after landing are advantageous for both migrants and host country.

Epidemiology and treatment outcome of MDR and pre-XDR TB in international migrants at two reference centers in the North of Italy: a cross-sectional study coordinated by Stop TB Italia Onlus

OBJECTIVE

We evaluated the epidemiology and treatment outcomes of multi-drug-resistant (MDR) and pre-extensively-resistant (pre-XDR) tuberculosis (TB) in migrants at two TB reference centers in Italy.

STUDY DESIGN

Patient selection criteria for the present study were as follows: age ≥18 years, international migrants (i.e., person who lives in a country other than his/her country of origin), MDR or pre-XDR-TB based on drug-susceptibility test findings, full availability of microbiological, radiological and clinical data. Non-intersecting populations between the two centers were selected. The primary outcome was the proportion of patients with a successful (i.e., cured and treatment completed) treatment outcome.

METHODS

A retrospective cross-sectional study was conducted, from 01/Jan/2000 to 01/Jan/2015, at the Regional TB Reference Centre of Lombardy Region, Villa Marelli Institute/ASST Niguarda Ca' Granda (Milan, Italy) and at the Reference Center for MDR-TB and HIV-TB, Eugenio Morelli Hospital ASST (Sondalo, Italy). All data were made anonymous. Qualitative and quantitative variables were collected in an ad hoc electronic database. The statistical software used for all computations was STATA version 15 (StataCorp, Texas, USA).

RESULTS

Overall, 116 MDR-TB and pre-XDR-TB cases were recorded: 82 (70.7%) MDR-TB and 34 (29.3%) pre-XDR-TB patients, respectively. The majority (53.5%) were from the World Health Organization European Region (excluding EU/EEA) and 75 (64.5%) were male. Median (interquartile range) age was 32 (26-39) years. TB/HIV coinfection was found in 12 (10.3%) patients. Pulmonary TB was diagnosed in 107/116 (92.2%) patients. Resistance to fluoroquinolones and second-line injectables was detected in 22/116 (19.0%) and 12/107 (11.2%) patients, respectively. Overall treatment success was reached in 95/116 (81.9%) cases.

CONCLUSION

Pre-XDR-TB in migrants coming from high-endemic countries represents a matter of concern; therefore, prevention and control activities targeted to high-risk populations are needed to progress toward TB elimination.

Molecular Epidemiology of Tuberculosis in British Columbia, Canada: A 10-Year Retrospective Study

Background

Understanding regional molecular epidemiology allows for the development of more efficient tuberculosis prevention strategies in low-incidence settings.

Methods

We analyzed 24-locus mycobacterial interspersed repetitive-unit–variable-number tandem repeat (MIRU-VNTR) genotyping for 2290 Mycobacterium tuberculosis clinical isolates collected in the province of British Columbia (BC), Canada, in 2005–2014. Laboratory data for each isolate were linked to case-level clinical and demographic data. These data were used to describe the molecular epidemiology of tuberculosis across the province.

Results

We detected >1500 distinct genotypes across the 4 major M. tuberculosis lineages, reflecting BC’s diverse population. Disease site and clustering rates varied across lineages, and MIRU-VNTR was used to group the 2290 isolates into 189 clusters (2–70 isolates per cluster), with an overall clustering rate of 42.4% and an estimated local transmission rate of 34.1%. Risk factors for clustering varied between Canadian-born and foreign-born individuals; the former had increased odds (odds ratio, 7.8; 95% confidence interval [CI], 6.2–9.6) of belonging to a genotypic cluster, although nearly one-quarter of clusters included both Canadian- and foreign-born persons. Large clusters (≥10 cases) occurred more frequently within the M. tuberculosis Euro-American lineage, and individual-level risk factors associated with belonging to a large cluster included being Canadian born (adjusted odds ratio, 3.3; 95% CI, 2.3–4.8), residing in a rural area (2.3; 1.2–4.5), and illicit drug use (2.0; 1.2–3.4).

Conclusions

Although tuberculosis in BC largely arises through reactivation of latent tuberculosis in foreign-born persons, locally transmitted infections occur in discrete populations with distinct disease and risk factor profiles, representing groups for targeted interventions.

The impact of migration on tuberculosis in the United States

Due to greater exposure to Mycobacterium tuberculosis infection before migration, migrants moving to low-incidence settings can experience substantially higher tuberculosis (TB) rates than the native-born population. This review describes the impact of migration on TB epidemiology in the United States, and how the TB burden differs between US-born and non-US-born populations. The United States has a long history of receiving migrants from other parts of the world, and TB among non-US-born individuals now represents the majority of new TB cases. Based on an analysis of TB cases among individuals from the top 30 countries of origin in terms of non-US-born TB burden between 2003 and 2015, we describe how TB risks vary within the non-US-born population according to age, years since entry, entry year, and country of origin. Variation along each of these dimensions is associated with more than 10-fold differences in the risk of developing active TB, and this risk is also positively associated with TB incidence estimates for the country of origin and the composition of the migrant pool in the entry year. Approximately 87 000 lifetime TB cases are predicted for the non-US-born population resident in the United States in 2015, and 5800 lifetime cases for the population entering the United States in 2015.

Defining a migrant-inclusive tuberculosis research agenda to end TB

BACKGROUND

Pillar 3 of the End TB Strategy calls for the promotion of research and innovation at the country level to facilitate improved implementation of existing and novel interventions to end tuberculosis (TB). In an era of increasing cross-border migration, there is a specific need to integrate migration-related issues into national TB research agendas. The objective of the present review is to provide a conceptual framework to guide countries in the development and operationalization of a migrant-inclusive TB research agenda.

METHODS

We conducted a literature review, complemented by expert opinion and the previous articles in this State of the Art series, to identify important themes central to migration-related TB. We categorized these themes into a framework for a migration-inclusive global TB research agenda across a comprehensive spectrum of research. We developed this conceptual framework taking into account: 1) the biomedical, social and structural determinants of TB; 2) the epidemiologic impact of the migration pathway; and 3) the feasibility of various types of research based on a country's capacity.

DISCUSSION

The conceptual framework presented here is based on the key principle that migrants are not inherently different from other populations in terms of susceptibility to known TB determinants, but that they often have exacerbated or additional risks related to their country of origin and the migration process, which must be accounted for in developing comprehensive TB prevention and care strategies. A migrant-inclusive research agenda should systematically consider this wider context to have the highest impact.

Transmission of tuberculosis and predictors of large clusters within three years in an urban setting in Tokyo, Japan: a population-based molecular epidemiological study

OBJECTIVE

Molecular epidemiology is a promising tool for understanding tuberculosis transmission dynamics but has not been sufficiently utilised in Asian countries including Japan. The aim of this study was to estimate the proportion of TB cases attributable to recent transmission and to identify risk factors of genotype clustering and the development of large clusters within 3 years in an urban setting in Japan.

DESIGN AND SETTING

Long-term cross-sectional observational study combining the characteristics of patients with culture-positive TB notified in Shinjuku City, Tokyo (2002-2013), with genotype data of Mycobacterium tuberculosis. PRIMARY OUTCOME MEASURE: Genotype clustering rate and association between genotype clustering status and explanatory variables.

RESULTS

Among 1025 cases, 515 were localised within 113 genotype clusters. The overall clustering rate was 39.2%. Significantly higher rates were found in patients aged <40 years (adjusted odds ratio (aOR)=1.73, 95% CI 1.23 to 2.44), native Japanese individuals (aOR=3.90, 95% CI 2.27 to 6.72), full-time workers (aOR=1.63, 95% CI 1.17 to 2.27), part-time/daily workers (aOR=2.20, 95% CI 1.35 to 3.58), individuals receiving public assistance (aOR=1.81, 95% CI 1.15 to 2.84) and homeless people (aOR=1.63, 95% CI 1.02 to 2.62). A significant predictor of large genotype clusters within 3 years was a registration interval ≤2 months between the first two cases in a cluster.

CONCLUSION

Our results indicated that a large proportion of patients with culture-positive TB were involved in the recent TB transmission chain. Foreign-born persons still have a limited impact on transmission in the Japanese urban setting. Intensified public health interventions, including the active case finding, need to focus on individuals with socioeconomic risk factors that are significantly associated with tuberculosis transmission and clusters with shorter registration intervals between the first two cases.

Vaccine-preventable diseases and immunisation coverage among migrants and non-migrants worldwide: A scoping review of published literature, 2006 to 2016

BACKGROUND

Studies of vaccine-preventable disease (VPD) burden and immunisation coverage among migrants compared to locally-born populations present a mixed picture on whether migrants experience disproportionate VPD rates and immunisation inequities, and what the associated factors are. We conducted a scoping review to explore differences in VPD burden and immunisation coverage between migrants and non-migrants worldwide.

METHODS

We followed Arksey and O'Malley's five stage scoping review method. We searched for empirical, peer-reviewed literature published in English that compared VPD burden and/or immunisation coverage between migrant and non-migrant groups published between 2006 and 2016 using MEDLINE, EMBASE, CINAHL, Sociological Abstracts, and Web of Science databases. Relevant information from the studies were charted in Microsoft Excel and results were summarised using a descriptive analytical method.

RESULTS

Forty-five studies met the inclusion criteria (n = 13 reporting on VPD burden; n = 27 reporting on immunisation rates; n = 5 reporting on both). Studies that met the criteria only reported findings from high income countries or high-middle income countries. Accounting for results that were presented according to separate ethnic migrant sub-groups, almost all of the studies comparing VPD burden (n = 17, 89%) reported higher burden among migrants compared to non-migrants, while most studies measuring immunisation rates (n = 26, 70%) noted lower rates among migrants. Numerous factors contributed to these findings, including the influence of migrants' nativity, socio-economic status, migration background, generation status, residential duration, cultural/personal beliefs, language proficiency and healthcare utilisation.

CONCLUSIONS

Considerable variability of study foci and methodologies limited our ability to make definitive conclusions and comparisons, but the literature suggests that migrant populations generally experience higher VPD burden and lower immunisation rates. The findings highlight a number of important considerations for future research and immunisation programme planning. Future research should explore factors that influence VPD burden and immunisation rates, and strategies to overcome barriers to vaccine uptake among migrants.

Migration Medicine

Migration is increasing and practitioners need to be aware of the unique health needs of this population. The prevalence of infectious diseases among migrants varies and generally mirrors that of their countries of origin, but is modified by the circumstance of migration, the presence of pre-arrival screening programs and post arrival access to health care. To optimize the health of migrants practitioners; (1) should take all opportunities to screen migrants at risk for latent infections such as tuberculosis, chronic hepatitis B and C, HIV, strongyloidiasis, schistosomiasis and Chagas disease, (2) update routine vaccines in all age groups and, (3) be aware of "rare and tropical infections" related to migration and return travel.

Simplified Model to Survey Tuberculosis Transmission in Countries Without Systematic Molecular Epidemiology Programs

Systematic molecular/genomic epidemiology studies for tuberculosis surveillance cannot be implemented in many countries. We selected Panama as a model for an alternative strategy. Mycobacterial interspersed repetitive unit-variable-number tandem-repeat (MIRU-VNTR) analysis revealed a high proportion (50%) of Mycobacterium tuberculosis isolates included in 6 clusters (A-F) in 2 provinces (Panama and Colon). Cluster A corresponded to the Beijing sublineage. Whole-genome sequencing (WGS) differentiated clusters due to active recent transmission, with low single-nucleotide polymorphism-based diversity (cluster C), from clusters involving long-term prevalent strains with higher diversity (clusters A, B). Prospective application in Panama of 3 tailored strain-specific PCRs targeting marker single-nucleotide polymorphisms identified from WGS data revealed that 31.4% of incident cases involved strains A-C and that the Beijing strain was highly represented and restricted mainly to Colon. Rational integration of MIRU-VNTR, WGS, and tailored strain-specific PCRs could be a new model for tuberculosis surveillance in countries without molecular/genomic epidemiology programs.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Infectious diseases at different stages of migration: an expert review

BACKGROUND

Human migration is increasing in magnitude and scope. The majority of migrants arriving in high-income countries originate from countries with a high prevalence of infectious diseases. The risk and burden of infectious diseases are not equally distributed among migrant groups and vary with migration stage.

METHODS

A broad literature review was conducted on the drivers for infectious diseases and associated health outcomes among migrants across different stages of migration. The aim was to provide practitioners with an overview of the key infectious disease risks at each stage to guide health promotion strategies.

RESULTS

A complex interaction of factors leads to infectious diseases and associated poor health outcomes among migrants. The most important drivers are the epidemiology of infectious diseases in their countries of origin, the circumstances and conditions of the migration journey and barriers accessing healthcare post-arrival. During the recent large waves of forced migration into Europe, the primary health concerns on arrival were psychological, traumatic and chronic non-communicable diseases. In the early settlement period, crowded and unhygienic living conditions in reception camps facilitated outbreaks of respiratory, gastrointestinal, skin infections and vaccine preventable diseases. After re-settlement, undetected and untreated latent infections due to tuberculosis, viral hepatitis, HIV, chronic helminthiasis and Chagas' disease led to poor health outcomes. Migrants are disproportionally affected by preventable travel-related diseases such as malaria, typhoid and hepatitis due to poor uptake of pre-travel prophylaxis and vaccination. Infectious diseases among migrants can be decreased at all migration stages with health promotion strategies adapted to their specific needs and delivered in a linguistically and culturally sensitive manner.

CONCLUSIONS

Tailored health promotion and screening approaches and accessible and responsive health systems, regardless of legal status, will be needed at all migration stages to limit the burden and transmission of infectious diseases in the migrant population.

Migration and health: A retrospective study about the prevalence of HBV, HIV, HCV, tuberculosis and syphilis infections amongst newly arrived migrants screened at the Infectious Diseases Unit of Modena, Italy

INTRODUCTION

Aim of the study is to evaluate the prevalence of HBV, HIV, HCV, tuberculosis and syphilis infection among immigrants assigned to the immigrant centre of the province of Modena.

METHODS

At the time of arrival all immigrant were tested for: HBsAg, HBsAb, HBcAb, Ag p24/HIVAb, HCVAb, RPR, TPPA, Mantoux test (>10mm diameter of induration was considered to be positive), Chest X-rays. In case of positive samples, second level tests were performed (HbeAg, HBeAb, HDVAb, and baseline management and treatment of the infection detected).

RESULTS

A total of 304 immigrant people were enrolled in the study. HBsAg positivity was 12.2%, HCVAb 3.3%, HIVAb 1.6%, TPPA+RPR positivity in the 0.7%; 10.2% had a positive Mantoux test; 5.6% had Chest X-rays positive for signs of infection and 6 patients had an active tuberculosis. 83.8% HBsAg were HBeAb positive/HBeAg negative. HDVAb resulted positive in 1 patient (2.7%). Previous HBV infection was detected in 28.6% of cases, isolated HBcAb in 2.3%; 5.6% of patients resulted to be positive to HbsAb alone (probable vaccinated).

CONCLUSION

Our study confirms the high prevalence of HBsAg positivity and latent tuberculosis among immigrants, underlying the importance of screening for infections in this special population.

Understanding Tuberculosis Transmission in the United Kingdom: Findings From 6 Years of Mycobacterial Interspersed Repetitive Unit-Variable Number Tandem Repeats Strain Typing, 2010-2015

Genotyping provides the opportunity to better understand tuberculosis (TB) transmission. We utilized strain typing data to assess trends in the proportion of clustering and identify the characteristics of individuals and clusters associated with recent United Kingdom (UK) transmission. In this retrospective cohort analysis, we included all culture-confirmed strain-typed TB notifications from the UK between 2010 and 2015 to estimate the proportion of patients that clustered over time. We explored the characteristics of patients in a cluster using multivariable logistic regression. Overall, 58.5% of TB patients were concentrated in 2,701 clusters. The proportion of patients in a cluster decreased between 2010 (58.7%) and 2015 (55.3%) (P = 0.001). Being a clustered patient was associated with being male and UK-born, having pulmonary disease, having a previous TB diagnosis, and having a history of drug misuse or imprisonment. Our results suggest that TB transmission in the UK decreased between 2010 and 2015, during which time TB incidence also decreased. Targeted cluster investigation and extended contact tracing should be aimed at persons at risk of being in a transmission chain, including UK-born individuals with social risk factors in clusters with a high proportion of patients having pulmonary disease.

Genome-based transmission modelling separates imported tuberculosis from recent transmission within an immigrant population

In many countries the incidence of tuberculosis (TB) is low and is largely shaped by immigrant populations from high-burden countries. This is the case in Norway, where more than 80 % of TB cases are found among immigrants from high-incidence countries. A variable latent period, low rates of evolution and structured social networks make separating import from within-border transmission a major conundrum to TB control efforts in many low-incidence countries. Clinical Mycobacterium tuberculosis isolates belonging to an unusually large genotype cluster associated with people born in the Horn of Africa have been identified in Norway over the last two decades. We modelled transmission based on whole-genome sequence data to estimate infection times for individual patients. By contrasting these estimates with time of arrival in Norway, we estimate on a case-by-case basis whether patients were likely to have been infected before or after arrival. Independent import was responsible for the majority of cases, but we estimate that about one-quarter of the patients had contracted TB in Norway. This study illuminates the transmission dynamics within an immigrant community. Our approach is broadly applicable to many settings where TB control programmes can benefit from understanding when and where patients acquired TB.

Drivers of migration: why do people move?

More than 244 million international migrants were estimated to live in a foreign country in 2015, leaving apart the massive number of people that have been relocated in their own country. Furthermore, a substantial proportion of international migrants from southern countries do not reach western nations but resettle in neighbouring low-income countries in the same geographical area. Migration is a complex phenomenon, where 'macro'-, 'meso'- and 'micro'-factors act together to inform the final individual decision to migrate, integrating the simpler previous push-pull theory.Among the 'macro-factors', the political, demographic, socio-economic and environmental situations are major contributors to migration. These are the main drivers of forced migration, either international or internal, and largely out of individuals' control.Among the 'meso-factors', communication technology, land grabbing and diasporic links play an important role. In particular, social media attract people out of their origin countries by raising awareness of living conditions in the affluent world, albeit often grossly exaggerated, with the diaspora link also acting as an attractor. However, 'micro-factors' such as education, religion, marital status and personal attitude to migration also have a key role in making the final decision to migrate an individual choice. The stereotype of the illiterate, poor and rural migrant reaching the borders of affluent countries has to be abandoned. The poorest people simply do not have the means to escape war and poverty and remain trapped in their country or in the neighbouring one.Once in the destination country, migrants have to undergo a difficult and often conflictive integration process in the hosting community. From the health standpoint, newly arrived migrants are mostly healthy (healthy migrant effect), but they may harbour latent infections that need appropriate screening policies. Cultural barriers may sometimes hamper the relation between the migrant patient and the health care provider. The acquisition of western lifestyles is leading to an increase of non-communicable chronic diseases that require attention.Destination countries have to reconsider the positive medium/long-term potential of migration and need to be prepared to receive migrants for the benefit of the migrants themselves and their native population.

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.

Reduction in tuberculosis incidence in the UK from 2011 to 2015: a population-based study

BACKGROUND

Following nearly two decades of increasing tuberculosis in the UK, TB incidence decreased by 32% from 2011 to 2015. Explaining this reduction is crucial to informing ongoing TB control efforts.

METHODS

We stratified TB cases notified in the UK and TB cases averted in the UK through pre-entry screening (PES) between 2011 and 2015 by country of birth and time since arrival. We used population estimates and migration data to establish denominators, and calculated incidence rate ratios (IRRs) between 2011 and 2015. We calculated the contribution of changing migrant population sizes, PES and changes in TB rates to the reduction in TB notifications.

RESULTS

TB IRRs fell in all non-EU migrant and UK-born populations between 2011 and 2015 (0.61; 95%  CI 0.59 to 0.64 and 0.78; 0.73 to 0.83 respectively), with the greatest decrease in recent non-EU migrants (0.54; 0.48 to 0.61). 61.9% of the reduction in TB notifications was attributable to decreases in TB rates, 33.4% to a fall in the number of recent/mid-term non-EU migrants and 11.4% to PES. A small increase in notifications in EU-born migrants offset the reduction by 6.6%.

CONCLUSIONS

Large decreases in TB rates in almost all populations accounted for the majority of the reduction in TB notifications, providing evidence of the impact of recent interventions to improve UK TB control. The particularly large decrease in TB rates in recent non-EU migrants provides evidence of the effectiveness of screening interventions that target this population. These findings will inform ongoing improvements to TB control.

Notifiable infectious diseases in refugees and asylum seekers: experience from a major reception center in Munich, Germany

PURPOSE

In 2016, the number of refugees worldwide reached 65.6 million. So far, only limited data are available on the health status of refugees and asylum seekers (RAs). Especially, notifiable infectious diseases (NIDs) carry the risk of outbreaks in communal accommodations hosting RAs.

METHODS

We conducted a monocentric retrolective cross-sectional study including 15,137 RAs treated in a special health care unit for RAs located in the major reception center in Munich from November 2014 to October 2016. Altogether 811 RAs with NIDs according to sections 6 and 7 of the German Infection Protection Act or with other infections relevant in the setting of a communal accommodation (RIDs) could be identified.

RESULTS

The gender and age distribution was generally comparable to that of refugees in Germany. However, patients from East Africa and Nigeria were significantly overrepresented. NIDs/RIDs were dominated by cases of tuberculosis, hepatitis B, and vaccine-preventable and parasitic diseases. Significant risk factors included country of origin (COI) and age for hepatitis B, age for hepatitis C, gender and age for HIV, and COI, gender and age for tuberculosis and ectoparasitosis. Calculated prevalences of hepatitis B, hepatitis C, and HIV were mostly below those of the COI. Incidences of tuberculosis were mostly strongly elevated.

CONCLUSIONS

COI, gender, and age have an impact on the occurrence of NIDs/RIDs. Early vaccinations and improved hygiene could be effective in preventing NIDs/RIDs in communal accommodations. Screening, prompt therapy, and infection protection measures are necessary to prevent the transmission of diseases.

Molecular epidemiology of tuberculosis in Tasmania and genomic characterisation of its first known multi-drug resistant case

Background

The origin and spread of tuberculosis (TB) in Tasmania and the types of strains of Mycobacterium tuberculosis complex (MTBC) present in the population are largely unknown.

Objective

The aim of this study was to perform the first genomic analysis of MTBC isolates from Tasmania to better understand the epidemiology of TB in the state.

Methods

Whole-genome sequencing was performed on cultured isolates of MTBC collected from 2014–2016. Single-locus variant analysis was applied to determine the phylogeny of the isolates and the presence of drug-resistance mutations. The genomic data were then cross-referenced against public health surveillance records on each of the cases.

Results

We determined that 83.3% of TB cases in Tasmania from 2014–2016 occurred in non-Australian born individuals. Two possible TB clusters were identified based on single locus variant analysis, one from November-December 2014 (n = 2), with the second from May-August 2015 (n = 4). We report here the first known isolate of multi-drug resistant (MDR) M. tuberculosis in Tasmania from 2016 for which we established its drug resistance mutations and potential overseas origin. In addition, we characterised a case of M. bovis TB in a Tasmanian-born person who presented in 2014, approximately 40 years after the last confirmed case in the state’s bovids.

Conclusions

TB in Tasmania is predominantly of overseas origin with genotypically-unique drug-susceptible isolates of M. tuberculosis. However, the state also exhibits features of TB that are observed in other jurisdictions, namely, the clustering of cases, and drug resistance. Early detection of TB and contact tracing, particularly of overseas-born cases, coordinated with rapid laboratory drug-susceptibility testing and molecular typing, will be essential for Tasmania to reach the World Health Organisation’s TB eradication goals for low-incidence settings.

A Predominant Variable-Number Tandem-Repeat Cluster of Mycobacterium tuberculosis Isolates among Asylum Seekers in the Netherlands and Denmark, Deciphered by Whole-Genome Sequencing

In many countries, Mycobacterium tuberculosis isolates are routinely subjected to variable-number tandem-repeat (VNTR) typing to investigate M. tuberculosis transmission. Unexpectedly, cross-border clusters were identified among African refugees in the Netherlands and Denmark, although transmission in those countries was unlikely. Whole-genome sequencing (WGS) was applied to analyze transmission in depth and to assess the precision of VNTR typing. WGS was applied to 40 M. tuberculosis isolates from refugees in the Netherlands and Denmark (most of whom were from the Horn of Africa) that shared the exact same VNTR profile. Cluster investigations were undertaken to identify in-country epidemiological links. Combining WGS results for the isolates (all members of the central Asian strain [CAS]/Delhi genotype), from both European countries, an average genetic distance of 80 single-nucleotide polymorphisms (SNPs) (maximum, 153 SNPs) was observed. The few pairs of isolates with confirmed epidemiological links, except for one pair, had a maximum distance of 12 SNPs. WGS divided this refugee cluster into several subclusters of patients from the same country of origin. Although the M. tuberculosis cases, mainly originating from African countries, shared the exact same VNTR profile, most were clearly distinguished by WGS. The average genetic distance in this specific VNTR cluster was 2 times greater than that in other VNTR clusters. Thus, identical VNTR profiles did not represent recent direct M. tuberculosis transmission for this group of patients. It appears that either these strains from Africa are extremely conserved genetically or there is ongoing transmission of this genotype among refugees on their long migration routes from Africa to Europe.

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.

Tuberculosis, human rights and ethics considerations along the route of a highly vulnerable migrant from sub-Saharan Africa to Europe

Migrant health is a critical public health issue, and in many countries attention to this topic has focused on the link between migration and communicable diseases, including tuberculosis (TB). When creating public health policies to address the complex challenges posed by TB and migration, countries should focus these policies on evidence, ethics, and human rights. This paper traces a commonly used migration route from sub-Saharan Africa to Europe, identifying situations at each stage in which human rights and ethical values might be affected in relation to TB care. This illustration provides the basis for discussing TB and migration from the perspective of human rights, with a focus on the right to health. We then highlight three strands of discussion in the ethics and justice literature in an effort to develop more comprehensive ethics of migrant health. These strands include theories of global justice and global health ethics, the creation of 'firewalls' to separate enforcement of immigration law from protection of human rights, and the importance of non-stigmatization to health justice. The paper closes by reflecting briefly on how TB programs can better incorporate human rights and ethical principles and values into public health practice.

Health problems of newly arrived migrants and refugees in Europe

BACKGROUND

The number of migrants and refugees in Europe in the past few years has increased dramatically due to war, violence or prosecutions in their homeland. Migration may affect physical, mental and social health. The objective of this article is to assess migrants and refugees' health problems, and to recommend appropriate interventions.

METHODS

A PubMed search of published articles on health problems of newly arrived migrants and refugees was conducted from 2003 through 2016, focusing on the current refugee crisis in Europe.

RESULTS

In addition to communicable diseases, such as respiratory, gastrointestinal and dermatologic infections, non-communicable diseases, including chronic conditions, mental and social problems, account for a significant morbidity burden in newly arrived migrants and refugees. Vaccine-preventable diseases are also of outmost importance. The appropriate management of newly arrived refugees and migrants' health problems is affected by barriers to access to health care including legal, communication, cultural and bureaucratic difficulties. There is diversity and lack of integration regarding health care provision across Europe due to policy differences between health care systems and social services.

CONCLUSION

There is a notable burden of communicable and non-communicable diseases among newly arrived migrants and refugees. Provision of health care at reception and temporary centres should be integrated and provided by a multidisciplinary team Appropriate health care of migrants and refugees could greatly enhance their health and social status which will benefit also the host countries at large.

A joint cross-border investigation of a cluster of multidrug-resistant tuberculosis in Austria, Romania and Germany in 2014 using classic, genotyping and whole genome sequencing methods: lessons learnt

Molecular surveillance of multidrug-resistant tuberculosis (MDR-TB) using 24-loci MIRU-VNTR in the European Union suggests the occurrence of international transmission. In early 2014, Austria detected a molecular MDR-TB cluster of five isolates. Links to Romania and Germany prompted the three countries to investigate possible cross-border MDR-TB transmission jointly. We searched genotyping databases, genotyped additional isolates from Romania, used whole genome sequencing (WGS) to infer putative transmission links, and investigated pairwise epidemiological links and patient mobility. Ten isolates from 10 patients shared the same 24-loci MIRU-VNTR pattern. Within this cluster, WGS defined two subgroups of four patients each. The first comprised an MDR-TB patient from Romania who had sought medical care in Austria and two patients from Austria. The second comprised patients, two of them epidemiologically linked, who lived in three different countries but had the same city of provenance in Romania. Our findings strongly suggested that the two cases in Austrian citizens resulted from a newly introduced MDR-TB strain, followed by domestic transmission. For the other cases, transmission probably occurred in the same city of provenance. To prevent further MDR-TB transmission, we need to ensure universal access to early and adequate therapy and collaborate closely in tuberculosis care beyond administrative borders.

Yield of active screening for tuberculosis among asylum seekers in Germany: a systematic review and meta-analysis

All asylum seekers in Germany undergo upon-entry screening for tuberculosis TB, but comprehensive evidence on the yield is lacking. We compared the national estimates with the international literature in a systematic review and meta-analysis of studies reporting the yield of TB, defined as the fraction of active TB cases detected among asylum seekers screened in Germany upon entry. We searched 11 national and international databases for empirical studies and the internet for grey literature published in English or German without restrictions on publication time. Among 1,253 screened articles, we identified six articles reporting the yield of active TB based on German data, ranging from 0.72 (95% confidence interval (CI): 0.45-1.10) to 6.41 (95% CI: 4.19-9.37) per 1,000 asylum seekers. The pooled estimate across all studies was 3.47 (95% CI: 1.78-5.73; I2 = 94.9%; p < 0.0001) per 1,000 asylum seekers. This estimate was in line with international evidence (I2 = 0%; p for heterogeneity 0.55). The meta-analysis of available international estimates resulted in a pooled yield of 3.04 (95% CI: 2.24-3.96) per 1,000. This study provides an estimate across several German federal states for the yield of TB screening in asylum seekers. Further research is needed to develop more targeted screening programmes.

Migration and infectious diseases

BACKGROUND

Infectious diseases still represent an important cause of morbidity and mortality among foreign-born individuals. The rising migration flows towards Europe throughout the last few years are raising renewed concerns about management issues and the potential associated risk for the native population.

AIMS

To discuss the health implications and challenges related to the four phases of migration, from first arrival to stable resettlement.

SOURCES

Scientific literature and relevant statistical reports.

CONTENT

Although infectious diseases are not a health priority at first arrival, a syndromic screening to identify the most common communicable conditions (pulmonary tuberculosis above all) should be promptly conducted. Reception centres where asylum seekers are gathered after arrival may be crowded, so favouring epidemic outbreaks, sometimes caused by incomplete vaccine coverage for preventable diseases. After resettlement, the prevalence of some chronic infections such as human immunodeficiency virus, viral hepatitis or tuberculosis largely reflects the epidemiological pattern in the country of origin, with poor living conditions being an additional driver. Once resettled, migrants usually travel back to their country of origin without seeking pre-travel advice, which results in a high incidence of malaria and other infections.

IMPLICATIONS

Although infectious diseases among migrants are known to have a negligible impact on European epidemiology, screening programmes need to be implemented and adapted to the different stages of the migratory process to better understand the trends and set priorities for action. Appropriate access to care regardless of the legal status is crucial to improve the health status and prevent the spread of contagious conditions.

Breaking the barriers: Migrants and tuberculosis

Tuberculosis (TB) can represent an important clinical and public health in developing and developed countries. Low- and middle-income countries are facing an epidemic which is difficult to address because of the drug-resistance spread and the association of TB with HIV/AIDS. High-income countries, whose TB incidence has decreased in the last decades, can be involved in new TB epidemic waves owing to social, healthcare, and economic hurdles and challenges. In particular, migrants coming from high TB incidence countries can represent a new epidemiological issue in the TB care and control in geographical areas where primary care and specialized centres are not equipped to face the clinical and public health issues associated with the TB disease. The healthcare management of individuals with a latent TB infection or the TB disease is heterogeneous and different policies are in place in Europe, and, specifically, in EU countries. Scientific evidence on how to early and efficiently detect TB cases is missing, as well as diagnostic tools to diagnose those who have latent TB infection do not show adequate accuracy. Countries like Greece and Italy have political difficulties in the management of migrants and the poor living conditions in the migration centres can increase the probability of Mycobacterium tuberculosis transmission. A clear advocacy and political commitment are urgently required. The current migration trends represent a threat from a human and a healthcare perspective. New homogeneous and target-oriented policies and strategies are needed to improve the health of the migrant and of the autochthonous populations.

Molecular epidemiology of Mycobacterium tuberculosis complex in Brussels, 2010-2013

The tuberculosis (TB) incidence rate in Brussels-Capital Region is 3-fold higher than in Belgium as a whole. Eight years after the realization of initial prospective population-based molecular epidemiology investigations in this Region, a similar study over the period 2010–2013 was conducted. TB strains isolated from 945 patients were submitted to genotyping by standardized 24-locus-MIRU-VNTR typing and spoligotyping. The phylogenetic analysis showed that the LAM (16.7%) and Haarlem (15.7%) branches are the two most prevalent TB lineages circulating in Brussels. Analysis of the MDR subgroup showed an association with Beijing strains (39.9%) and patients native of Eastern Europe (40.7%). Genotyping detected 113 clusters involving 321 patients, giving a recent transmission index of 22.9%. Molecular-guided epidemiological investigations and routine surveillance activities revealed family transmission or social contact for patients distributed over 34 clusters. Most of the patients were foreign-born (75.7%). However, cluster analysis revealed only limited trans-national transmission. Comparison with the previous study shows a stable epidemiological situation except for the mean age difference between Belgian-born and foreign-born patients which has disappeared. This study confirms that molecular epidemiology has become an important determinant for TB control programs. However, sufficient financial means need to be available to perform all required epidemiological investigations.

Tuberculosis Outbreak in an Educational Institution in Norway

Within 1 week in April 2013, three cases of pulmonary tuberculosis (TB) were reported among students attending training sessions at an educational institution in Oslo, Norway. By the end of October 2013, a total of nine epidemiologically linked cases had been reported. The outbreak encompassed a total of 24 cases from 2009 to 2014, among which all of the 22 Mycobacterium tuberculosis isolates available had identical mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) profiles (MtbC15-9 code 10287-189) belonging to the Beijing lineage. Whole-genome sequencing (WGS) of the M. tuberculosis isolates revealed 20 variable nucleotide positions within the cluster, indicating a clonal outbreak. The most likely index case was identified and diagnosed in Norway in 2009 but was born in Asia. WGS analyses verified that all of the cases were indeed part of a single transmission chain. However, even when combining WGS and intensified contact tracing, we were unable to fully reconstruct the TB transmission events.

Tackling TB in low-incidence countries: improving diagnosis and management in vulnerable populations

In low tuberculosis incidence regions, tuberculosis is mainly concentrated among hard-to-reach populations like migrants, homeless people, drug or alcohol abusers, prisoners and people living with HIV. To be able to eliminate tuberculosis from these low incidence regions tuberculosis screening and treatment programs should focus on these hard-to-reach populations. Here we discuss the barriers and facilitators of health care-seeking, interventions improving tuberculosis screening uptake and interventions improving treatment adherence in these hard-to-reach populations.

Tuberculosis in Sardinia: An investigation into the relationship between natives and immigrants

OBJECTIVE/BACKGROUND

Tuberculosis (TB) has had a recrudescence in the last few decades in Italy as a result of many factors, among which migration from countries where TB is endemic is one of them. In Sardinia, a major island of Italy, there was no knowledge of the mechanisms of transmission of TB in the immigrant subpopulation and the impact it may have on the native subpopulation and on the community as a whole. Therefore, a molecular epidemiological study was carried out to get a clearer picture of the number and genetic features of Mycobacterium tuberculosis strains isolated from immigrants and from natives in Sardinia.

METHODS

Two groups of clinical isolates of M. tuberculosis, one collected from immigrants and the other one from Sardinians, were analyzed in this study. The genotyping was executed through the variable number tandem repeat-mycobacterial interspersed repetitive units technique and a first-line antimycobacterial drug-susceptibility test was also carried out.

RESULTS

Thirty-six clinical isolates from immigrants and 25 from Sardinians were analyzed. Variable number tandem repeat-mycobacterial interspersed repetitive units technique showed that all of them belonged to different strains and there was a quite high allelic diversity among them. Moreover, data collected allowed the finding of, with a good approximation, the phylogenetic relations among the strains isolated and the best-known phylogenetic groups.

CONCLUSION

The study pointed out that since every strain is different, there was no TB transmission in any of the subpopulations and between immigrants and natives. This showed that the presence of immigrants was not a risk factor for contracting TB in the community.

Methodological and Clinical Aspects of the Molecular Epidemiology of Mycobacterium tuberculosis and Other Mycobacteria

Molecular typing has revolutionized epidemiological studies of infectious diseases, including those of a mycobacterial etiology. With the advent of fingerprinting techniques, many traditional concepts regarding transmission, infectivity, or pathogenicity of mycobacterial bacilli have been revisited, and their conventional interpretations have been challenged. Since the mid-1990s, when the first typing methods were introduced, a plethora of other modalities have been proposed. So-called molecular epidemiology has become an essential subdiscipline of modern mycobacteriology. It serves as a resource for understanding the key issues in the epidemiology of tuberculosis and other mycobacterial diseases. Among these issues are disclosing sources of infection, quantifying recent transmission, identifying transmission links, discerning reinfection from relapse, tracking the geographic distribution and clonal expansion of specific strains, and exploring the genetic mechanisms underlying specific phenotypic traits, including virulence, organ tropism, transmissibility, or drug resistance. Since genotyping continues to unravel the biology of mycobacteria, it offers enormous promise in the fight against and prevention of the diseases caused by these pathogens. In this review, molecular typing methods for Mycobacterium tuberculosis and nontuberculous mycobacteria elaborated over the last 2 decades are summarized. The relevance of these methods to the epidemiological investigation, diagnosis, evolution, and control of mycobacterial diseases is discussed.

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.

The effect of migration within the European Union/European Economic Area on the distribution of tuberculosis, 2007 to 2013

Immigration from tuberculosis (TB) high-incidence countries is known to contribute notably to the TB burden in low-incidence countries. However, the effect of migration enabled by the free movement of persons within the European Union (EU)/European Economic Area (EEA) on TB notification has not been analysed. We analysed TB surveillance data from 29 EU/EEA countries submitted for the years 2007-2013 to The European Surveillance System. We used place of birth and nationality as proxy indicators for native, other EU/EEA and non-EU/EEA origin of the TB cases and analysed the characteristics of the subgroups by origin. From 2007-2013, a total of 527,467 TB cases were reported, of which 129,781 (24.6%) were of foreign origin including 12,566 (2.4%) originating from EU/EEA countries other than the reporting country. The countries reporting most TB cases originating from other EU/EEA countries were Germany and Italy, and the largest proportion of TB cases in individuals came from Poland (n=1,562) and Romania (n=6,285). At EU/EEA level only a small proportion of foreign TB cases originated from other EU/EEA countries, however, the uneven distribution of this presumed importation may pose a challenge to TB programmes in some countries.

Relating annual migration from high tuberculosis burden country of origin to changes in foreign-born tuberculosis notification rates in low-medium incidence European countries

The level of immigration from high tuberculosis (TB) burden countries (HBCs) which impacts on the foreign-born TB notification rate is largely unknown. In this work, we performed a cross-sectional analysis of epidemiological data from 2000 to 2013 from nine European countries: Austria, Denmark, Finland, Hungary, Netherlands, Norway, Spain, Sweden, and the United Kingdom. Crude notification rates were calculated for foreign- and native-born populations and a multiple-linear regression model predicting notification rates with HBC population data was generated. From 2000 to 2013, the population percentage with a foreign birthplace increased on average each year in all nine countries, ranging from +0.11%/year in the Netherlands to +0.66%/year in Spain. An annual increase in HBC migrants above +0.43% per year (95% Confidence Interval: 0.24%-0.63%) corresponded with higher TB notification rates in the foreign-born population of the countries analyzed. This indicates that migration from HBCs can exert a measurable effect on the foreign-born TB notification rate. However, an increase in the foreign-born TB notification rate coincided with an average annual rise in national TB notification rates only in countries, Norway (+3.85%/year) and Sweden (+2.64%/year), which have a high proportion (>80%) of TB cases that are foreign-born.

Risk of Active Tuberculosis among Index Case of Householders-A Long-Term Assessment after the Conventional Contacts Study

OBJECTIVES

The aim of this study was to determine the incidence of active tuberculosis (TB) among household contacts of TB-index cases diagnosed during a 7-year period in a public Primary Care Center located in a high-incidence area.

DESIGN AND SAMPLE

A retrospective cohort study was performed. Data collection was based on the capture-recapture method; the two main sources crossed information from TB-index and contact cases from the El Fondo Primary Care Center (Santa Coloma de Gramenet, Spain) and their reports to the National Epidemiologic Surveillance Service.

MEASURES

Variables were divided into demographic and health data (result of the Mantoux test, chest X-ray, presence of risk factors, and indication for chemoprophylaxis).

RESULTS

Community nurses identified 103 household contacts that underwent the conventional contact study. Overall, 60.19% were male; the mean age was 29.08 years. Only one case of secondary active TB was found, representing an incidence of 0.56% per TB-index case and year.

CONCLUSION

The incidence of new secondary TB among household contacts with TB-index cases was of a case. Nevertheless, a long-term follow-up of these householders beyond the conventional contacts study should be considered in areas with higher incidences of TB or among specific high-risk populations.

Contact investigation outcomes of Canadian-born adults with tuberculosis in Indigenous and non-Indigenous populations in Alberta

OBJECTIVES

Contact investigations are a critical component of tuberculosis control in high-income countries. However, the relative success of conventional methods by population group and place of residence is unknown. This study compares outcomes of contact investigations of Canadian-born Indigenous tuberculosis cases living on- and off-reserve with other Canadian-born cases.

METHODS

In a retrospective analysis, Canadian-born adult culture-positive pulmonary TB cases (2001-2010) were identified. Characteristics of source cases and their contacts were compared by population group. Outcomes of contact investigations, including completion of recommended investigations and preventive therapy, were compared in multivariable analysis.

RESULTS

Of 171 cases of tuberculosis identified, 49 (29%) were Indigenous on-reserve, 62 (36%) Indigenous off-reserve, and 60 (35%) non-Indigenous or Canadian-born, "other". Indigenous people had more contacts identified per case compared to non-Indigenous patients. Case population group and smear status were the main predictors of the success of contact investigations. Of those recommended preventive therapy, close contacts of Indigenous cases on-reserve had the highest rate of completion, at 54%, vs. 41% and 37% for close contacts of Indigenous living off-reserve and Canadian-born "other" respectively (p = 0.02). Contacts of Indigenous cases living off-reserve had the greatest delay in assessment and the lowest rates of completion of assessment and preventive therapy. In multivariable analysis, population group, smear status of source case and proximity of contact were predictors of preventive therapy acceptance and/or completion.

CONCLUSIONS

Significant differences in outcomes of contact investigations were observed between population groups. The higher priority of contacts of smear-positive cases appears to influence efficiency of service delivery, regardless of population group. Jurisdictional differences in program delivery, resource availability and perceived risk of transmission likely influence outcomes of contact investigations.

Molecular Typing of Mycobacterium Tuberculosis Strains: A Fundamental Tool for Tuberculosis Control and Elimination

Tuberculosis (TB) is still an important cause of morbidity and mortality worldwide. An improvement of the strategies for disease control is necessary in both low- and high-incidence TB countries. Clinicians, epidemiologists, laboratory specialists, and public health players should work together in order to achieve a significant reduction in TB transmission and spread of drug-resistant strains. Effective TB surveillance relies on early diagnosis of new cases, appropriate therapy, and accurate detection of outbreaks in the community, in order to implement proper TB control strategies. To achieve this goal, information from classical and molecular epidemiology, together with patient clinical data need to be combined. In this review, we summarize the methodologies currently used in molecular epidemiology, namely molecular typing. We will discuss their efficiency to phylogenetically characterize Mycobacterium tuberculosis isolates, and their ability to provide information that can be useful for disease control. We will also introduce next generation sequencing as the methodology that potentially could provide in a short time both, detection of new outbreaks and identification of resistance patterns. This could envision a potential of next generation sequencing as an important tool for accurate patient management and disease control.