Mycobacterium tuberculosis infection after travel to or contact with visitors from countries with a high prevalence of tuberculosis

Tuberculosis Screening, Testing, and Treatment of US Health Care Personnel: ACOEM and NTCA Joint Task Force on Implementation of the 2019 MMWR Recommendations

: On May 17, 2019, the US Centers for Disease Control and Prevention and National Tuberculosis Controllers Association issued new Recommendations for Tuberculosis Screening, Testing, and Treatment of Health Care Personnel, United States, 2019, updating the health care personnel-related sections of the Guidelines for Preventing the Transmission of Mycobacterium tuberculosis in Health-Care Settings, 2005. This companion document offers the collective effort and experience of occupational health, infectious disease, and public health experts from major academic and public health institutions across the United States and expands on each section of the 2019 recommendations to provide clarifications, explanations, and considerations that go beyond the 2019 recommendations to answer questions that may arise and to offer strategies for implementation.

Risk of latent and active tuberculosis infection in travellers: a systematic review and meta-analysis

INTRODUCTION

Achieving tuberculosis (TB) elimination in low TB incidence countries requires identification and treatment of individuals at risk for latent TB infection (LTBI). Persons travelling to high TB incidence countries are potentially at risk for TB exposure. This systematic review and meta-analysis estimates incident LTBI and active TB among individuals travelling from low to higher TB incidence countries.

METHODS

Five electronic databases were searched from inception to 18 February 2020. We identified incident LTBI and active TB among individuals travelling from low (<10 cases/100 000 population) to intermediate (10-100/100 000) or high (>100/100 000) TB incidence countries. We conducted a meta-analysis and meta-regression using a random effects model of log-transformed proportions (cumulative incidence). Subgroup analyses investigated the impact of travel duration, travel purpose and TB incidence in the destination country.

RESULTS

Our search identified 799 studies, 120 underwent full-text review, and 10 studies were included. These studies included 1 154 673 travellers observed between 1994 and 2013, comprising 443 health care workers (HCW), 1 068 636 military personnel and 85 594 general travellers/volunteers. We did not identify any studies that estimated incidence of LTBI or active TB among people travelling to visit friends and relatives (VFRs). The overall cumulative incidence of LTBI was 2.3%, with considerable heterogeneity. Among individuals travelling for a mean/median of up to 6 months, HCWs had the highest cumulative incidence of LTBI (4.3%), whereas the risk was lower for military (2.5%) and general travellers/volunteers (1.6%). Meta-regression did not identify a difference in incident LTBI based on travel duration and TB incidence in the destination country. Five studies reported cases of active TB, with an overall pooled estimate of 120.7 cases per 100 000 travellers.

CONCLUSIONS

We found that travelling HCWs were at highest risk of developing LTBI. Individual risk activities and travel purpose were most associated with risk of TB infection acquired during travel.

Tuberculosis infection in children visiting friends and relatives in countries with high incidence of tuberculosis: A study protocol

INTRODUCTION

Tuberculosis (TB) is a global infectious disease. In low-incidence countries, paediatric TB affects mostly immigrant children and children of immigrants. We hypothesize that these children are at risk of exposure to Mycobacterium tuberculosis when they travel to the country of origin of their parents to visit friends and relatives (VFR). In this study, we aim to estimate the incidence rate and risk factors associated to latent tuberculosis infection (LTBI) and TB in VFR children.

METHODS AND ANALYSIS

A prospective study will be carried out in collaboration with 21 primary health care centres (PCC) and 5 hospitals in Catalonia, Spain. The study participants are children under 15 years of age, either immigrant themselves or born to immigrant parents, who travel to countries with high incidence of TB (≥ 40 cases/100,000 inhabitants). A sample size of 492 children was calculated. Participants will be recruited before traveling, either during a visit to a travel clinic or to their PCC, where a questionnaire including sociodemographic, epidemiological and clinical data will be completed, and a tuberculin skin test (TST) will be performed and read after 48 to 72 hours; patients with a positive TST at baseline will be excluded. A visit will be scheduled eight to twelve-weeks after their return to perform a TST and a QuantiFERON-TB Gold Plus test. The incidence rate of LTBI will be estimated per individual/month and person/year per country visited, and also by age-group.

ETHICS AND DISSEMINATION

The study protocol was approved by the Clinical Research Ethics Committee of the Hospital Universitari Mútua Terrassa (code 02/16) and the Clinical Research Ethics Committee of the Fundació Institut Universitari per a la Recerca a l'Atenció Primària de Salut Jordi Gol i Gurina (code P16/094). Articles will be published in indexed scientific journals.

TRIAL REGISTRATION

Clinical-Trials.gov: NCT04236765.

Detailed characterisation of the tuberculosis epidemic in Western Sydney: a descriptive epidemiological study

Traditional tuberculosis (TB) epidemiology reports rarely provide a detailed analysis of TB incidence in particular geographic locations and among diverse population groups. Western Sydney Local Health District (WSLHD) has one of the highest TB incidence rates in Australia, and we explored whether more detailed epidemiological analysis could provide a better overview of the local disease dynamics.

Using multiple relevant data sources, we performed a retrospective descriptive study of TB cases diagnosed within the WSLHD from 2006 to 2015 with a specific focus on geographic hotspots and the population structure within these hotspots.

Over the study period nearly 90% of Western Sydney TB cases were born in a high TB incidence country. The TB disease burden was geographically concentrated in particular areas, with variable ethnic profiles in these different hotspots. The most common countries of birth were India (33.0%), the Philippines (11.4%) and China (8.8%). Among the local government areas in Western Sydney, Auburn had the highest average TB incidence (29.4 per 100 000) with exceptionally high population-specific TB incidence rates among people born in Nepal (average 223 per 100 000 population), Afghanistan (average 154 per 100 000 population) and India (average 143 per 100 000 population).

Similar to other highly cosmopolitan cities around the world, the TB burden in Sydney showed strong geographic concentration. Detailed analysis of TB patient and population profiles in Western Sydney should guide better contextualised and culturally appropriate public health strategies.

High migration from tuberculosis (TB)-endemic settings to Western Sydney is driving over-representation among TB cases of specific cultural groups within geographic “hotspots”, requiring contextualised and culturally appropriate public health strategieshttp://bit.ly/2LqusU9

Respiratory Infections

Respiratory tract infections (RTIs) are a common health problem of international travelers. Travelers may be at increased risk of RTIs due to travel itself (mingling and close quarters in airports, airplanes, cruise ships, and hotels), and due to unique exposure at travel destinations. The clinical spectrum of RTIs in travelers is broad and includes upper RTIs, pharyngitis, otitis, laryngitis, bronchitis, and pneumonia. Most travelers who acquire an RTI only develop mild disease, and only a minority seek medical attention. All travelers should be up to date on any indicated vaccines based on age and medical condition that prevent RTIs, including influenza, measles, pneumococcal diseases, Haemophilus influenzae b, Neisseria meningitidis, diphtheria, and pertussis.

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Respiratory tract infections (RTIs) are among the most common illnesses reported by travelers. Most RTIs are viral, involve the upper respiratory tract, and do not require specific diagnosis or treatment.

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Influenza is often considered the most important travel-related infection. Travelers play an integral role in the yearly and global spread of influenza.

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Lower RTIs, including pneumonia, often require antimicrobial therapy.

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High-risk groups such as infants, small children, the elderly, and subjects with chronic tracheobronchial or pulmonary disease are at increased risk of developing severe clinical consequences should infection occur. All international travelers should be immunized for seasonal influenza unless otherwise contraindicated, and travelers should be instructed in hand hygiene and sneeze and cough hygiene.

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All travelers should be up to date on any indicated vaccines that prevent RTIs, including measles, pneumococcal diseases, Haemophilus influenzae b (Hib), meningococcal disease, diphtheria, and pertussis.

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Travelers may be at increased risk of geographically restricted RTIs, and clinicians should be familiar with the major manifestations of these illnesses.

Using Reports of Latent Tuberculosis Infection Among Young Children to Identify Tuberculosis Transmission in New York City, 2006-2012

The presence of latent tuberculosis infection (LTBI) in young children indicates recent tuberculosis (TB) transmission. We reviewed surveillance reports of children with LTBI to assess whether more follow-up is needed to prevent TB in this high-risk population. Data on all children under 5 years of age who were reported by health-care providers or laboratories to the New York City Department of Health during 2006-2012 were abstracted from the TB surveillance and case management system, and those with LTBI were identified. Potential source cases, defined as any infectious TB case diagnosed in the 2 years before a child was reported and whose residence was within 0.5 miles (0.8 km) of the child's residence, were identified. Neighborhood risk factors for TB transmission were examined. Among 3,511 reports of children under age 5 years, 1,722 (49%) had LTBI. The children were aged 2.9 years, on average, and most (64%) had been born in the United States. A potential source case was identified for 92% of the children; 27 children lived in the same building as a TB patient. Children with potential source cases were more likely to reside in neighborhoods with high TB incidence, poverty, and population density. The high proportion of children born in the United States and the young average age of the cases imply that undetected TB transmission occurred. Monitoring reports could be used to identify places where transmission occurred, and additional investigation is needed to prevent TB disease.

Migration-related tuberculosis: epidemiology and characteristics of tuberculosis cases originating outside the European Union and European Economic Area, 2007 to 2013

Migrants arriving from high tuberculosis (TB)-incidence countries may pose a significant challenge to TB control programmes in the host country. TB surveillance data for 2007-2013 submitted to the European Surveillance System were analysed. Notified TB cases were stratified by origin and reporting country. The contribution of migrant TB cases to the TB epidemiology in EU/EEA countries was analysed. Migrant TB cases accounted for 17.4% (n = 92,039) of all TB cases reported in the EU/EEA in 2007-2013, continuously increasing from 13.6% in 2007 to 21.8% in 2013. Of 91,925 migrant cases with known country of origin, 29.3% were from the Eastern Mediterranean, 23.0% from south-east Asia, 21.4% from Africa, 13.4% from the World Health Organization European Region (excluding EU/EEA), and 12.9% from other regions. Of 46,499 migrant cases with known drug-susceptibility test results, 2.9% had multidrug-resistant TB, mainly (51.7%) originating from the European Region. The increasing contribution of TB in migrants from outside the EU/EEA to the TB burden in the EU/EEA is mainly due to a decrease in native TB cases. Especially in countries with a high proportion of TB cases in non-EU/EEA migrants, targeted prevention and control initiatives may be needed to progress towards TB elimination.

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

Background

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

Methods

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

Results

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

Conclusions

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

Extensively drug-resistant tuberculosis in a young child after travel to India

Extensively drug-resistant (XDR) tuberculosis is becoming increasingly prevalent worldwide, but little is known about XDR tuberculosis in young children. In this Grand Round we describe a 2-year-old child from the USA who developed pneumonia after a 3 month visit to India. Symptoms resolved with empirical first-line tuberculosis treatment; however, a XDR strain of Mycobacterium tuberculosis grew in culture. In the absence of clinical or microbiological markers, low-radiation exposure pulmonary CT imaging was used to monitor treatment response, and guide an individualised drug regimen. Management was complicated by delays in diagnosis, uncertainties about drug selection, and a scarcity of child-friendly formulations. Treatment has been successful so far, and the child is in remission. This report of XDR tuberculosis in a young child in the USA highlights the risks of acquiring drug-resistant tuberculosis overseas, and the unique challenges in management of tuberculosis in this susceptible population.

Risk Factors for Central Nervous System Tuberculosis

OBJECTIVES

To describe the epidemiology and factors associated with pediatric central nervous system (CNS) tuberculosis (TB) in California from 1993 to 2011.

METHODS

We analyzed California TB registry data for persons aged ≤18 years, comparing CNS TB cases versus non-CNS TB cases reported from 1993 to 2011. Factors associated with CNS TB and TB deaths were identified by using multivariate logistic regression.

RESULTS

A total of 200 CNS TB cases were reported. Compared with non-CNS TB case patients, CNS TB case patients were more likely to be aged <5 years (72.0% vs 43.6%; odds ratio [OR]: 3.8 [95% confidence interval (CI): 2.4-5.9]), US-born (82.0% vs 58.2%; OR: 3.3 [CI: 2.3-4.7]), and Hispanic (75.0% vs 63.2%; OR: 1.7 [CI: 1.3-2.4]). Among US-born CNS TB case patients (during 2010-2011), 76.5% had a foreign-born parent. Tuberculin skin test results were negative in 38.2% of 170 CNS TB cases tested. In multivariate analysis, age <5 years (adjusted odds ratio [aOR]: 3.3 [CI: 2.0-5.4]), US birth (aOR: 1.8 [CI 1.2-2.7]), and Hispanic ethnicity (aOR: 1.5 [CI: 1.1-2.1]) were associated with an increased risk of developing CNS TB. For deaths, CNS TB (aOR: 3.8 [CI: 1.4-9.9]) and culture positivity (aOR: 6.2 [CI: 2.2-17.3]) were associated with increased risk of death, whereas tuberculin skin test positivity (aOR: 0.1 [CI: 0.04-0.2]) was associated with decreased risk.

CONCLUSIONS

Subsets of children are at increased risk for CNS TB in California and may benefit from additional prevention efforts.

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.

Summary of the Statement on International Travellers Who Intend to Visit Friends and Relatives

BACKGROUND

Travellers intending to visit friends and relatives (VFRs) are a specific group of travellers who have been identified as having an increased risk of travel-related morbidity.

OBJECTIVE

To provide recommendations for risk reduction in international VFRs.

METHODS

Recommendations regarding VFRs were developed based on available travel medicine literature and CATMAT expert opinion. Specific travel-related risks, including infectious disease epidemiology and burden in this population, were reviewed and recommendations were provided to attempt to mitigate these risks. Previous CATMAT statements related to VFRs were referred to and reiterated.

RECOMMENDATIONS

Rates of travel-related illness in VFRs tend to be higher for many conditions. Disease-specific risk factors and recommendations are discussed throughout this Statement. CATMAT recommends that VFRs' vaccinations be up-to-date and they be counselled on the importance of various risk reduction activities such as the use of malaria prophylaxis, safe sex practices and injury prevention. Pre- and/or post-travel tuberculosis testing is indicated in certain situations.

CONCLUSION

The pre-travel health assessment is an important opportunity to address with VFRs issues regarding health beliefs, health behaviours, current health status and the possibility of pre-existing conditions. Discussions addressing the importance of adherence to health advice and potential challenges to achieving adherence may be necessary.

Paediatric travel medicine: vaccines and medications

The paediatric aspects of travel medicine can be complex, and individual advice is often required. Nonetheless, children are much more likely to acquire common infections than exotic tropical diseases whilst travelling. Important exceptions are malaria and tuberculosis, which are more frequent and severe in children. Overall, travellers' diarrhoea is the most common illness affecting travellers. This review discusses vaccines and medications that may be indicated for children who are travelling overseas. It focuses on immunizations that are given as part of the routine schedule, as well as those that are more specific to travel. Malaria and travellers' diarrhoea are also discussed.

Travel-related infections in children

Malaria, diarrhea, respiratory infections, and cutaneous larva migrans are common travel-related infections observed in children and adolescents returning from trips to developing countries. Children visiting friends and relatives are at the highest risk because few visit travel clinics before travel, their stays are longer, and the sites they visit are more rural. Clinicians must be able to prepare their pediatric-age travelers before departure with preventive education, prophylactic and self-treating medications, and vaccinations. Familiarity with the clinical manifestations and treatment of travel-related infections will secure prompt and effective therapy.

Cost-effectiveness of latent tuberculosis screening before steroid therapy for idiopathic nephrotic syndrome in children

BACKGROUND

Guidelines differ on screening recommendations for latent tuberculosis infection (LTBI) prior to immunosuppressive therapy. We aimed to determine the most cost-effective LTBI screening strategy before long-term steroid therapy in a child with new-onset idiopathic nephrotic syndrome.

STUDY DESIGN

Markov state-transition model.

SETTING & POPULATION

5-year-old boy with new-onset idiopathic nephrotic syndrome.

MODEL, PERSPECTIVE, & TIMEFRAME

The Markov model took a societal perspective over a lifetime horizon.

INTERVENTION

3 strategies were compared: universal tuberculin skin testing (TST), targeted screening using a risk-factor questionnaire, and no screening. A secondary model included the newer interferon γ release assays (IGRAs), requiring only one visit and having greater specificity than TST.

OUTCOMES

Marginal cost-effectiveness ratios (2010 US dollars) with effectiveness measured as quality-adjusted life-years (QALYs).

RESULTS

At an LTBI prevalence of 1.1% (the average US childhood prevalence in our base case), a no-screening strategy dominated ($2,201; 29.3356 QALYs) targeted screening ($2,218; 29.3356 QALYs) and universal TST ($2,481; 29.3347 QALYs). At a prevalence >10.3%, targeted screening with a risk-factor questionnaire was the most cost-effective option. Higher than a prevalence of 58.5%, universal TST was preferred. In the secondary model, targeted screening with a questionnaire followed by IGRA testing was cost-effective compared with no screening in the base case when the LTBI prevalence was >4.9%.

LIMITATIONS

There is no established gold standard for the diagnosis of LTBI. Results of any modeling task are limited by the accuracy of available data.

CONCLUSIONS

Prior to starting steroid therapy, only patients in areas with a high prevalence of LTBI will benefit from universal TST. As more evidence becomes available about the use of IGRA testing in children, the assay may become a component of cost-effective screening protocols in populations with a higher burden of LTBI.

Pediatric and adolescent tuberculosis in the United States, 2008-2010

OBJECTIVE

We examined heterogeneity among children and adolescents diagnosed with tuberculosis (TB) in the United States, and we investigated potential international TB exposure risk.

METHODS

We analyzed demographic and clinical characteristics by origin of birth for persons <18 years with verified case of incident TB disease reported to National TB Surveillance System from 2008 to 2010. We describe newly available data on parent or guardian countries of origin and history of having lived internationally for pediatric patients with TB (<15 years of age).

RESULTS

Of 2660 children and adolescents diagnosed with TB during 2008-2010, 822 (31%) were foreign-born; Mexico was the most frequently reported country of foreign birth. Over half (52%) of foreign-born patients diagnosed with TB were adolescents aged 13 to 17 years who had lived in the United States on average >3 years before TB diagnosis. Foreign-born pediatric patients with foreign-born parents were older (mean, 7.8 years) than foreign-born patients with US-born parents (4.2 years) or US-born patients (3.6 years). Among US-born pediatric patients, 66% had at least 1 foreign-born parent, which is >3 times the proportion in the general population. Only 25% of pediatric patients with TB diagnosed in the United States had no known international connection through family or residence history.

CONCLUSIONS

Three-quarters of pediatric patients with TB in the United States have potential TB exposures through foreign-born parents or residence outside the United States. Missed opportunities to prevent TB disease may occur if clinicians fail to assess all potential TB exposures during routine clinic visits.

Tuberculosis in travellers

Tuberculosis (TB) incidence is increasing in many countries which are popular with international travellers. The development of active TB is a two-stage process; the risk of acquiring new TB infection depends primarily on the risk of contact with an individual with infectious TB, and the risk of disease on the immune status of the newly infected person. The risk of TB infection is low for most holiday-makers, but among long-term travellers to countries with high TB incidence, the risk may be similar to that experienced by the local population (0.5-2.5% per year); the risk to people working in health care is particularly high. Effective pre-travel advice involves assessing the traveller's risk of TB infection and disease. Recommendations on the prevention of TB in travellers vary between countries. Possible strategies include avoidance of exposure; BCG vaccination; and tuberculin skin testing before and after travel, with preventive therapy for those whose post-travel skin tests indicate recent infection. For those at highest risk of progression to disease, there may be value in preventive therapy during travel to reduce the risk of new TB infection. Further information on the contribution of recent travel to incident TB in industrialised countries would be valuable.

Fever of Unknown Origin in a Swiss-Born Child: Don’t Miss Tuberculosis!

Tuberculosis incidence is low in Switzer land. We report here on a Swiss-born toddler. Tuberculosis manifested with a fever of unknown origin, mimicking an inflammatory or autoimmune disorder triggering a high dose of corticosteroid treatment. The disease went unrecognized for several weeks until development of a miliary tuberculosis with advanced central nervous system involvement. This case highlights the difficulties encountered in diagnosing tuberculosis and in identifying the origin of this case. It reminds us that this disease must never be forgotten when facing a child with persistent fever who must be screened for, before starting immunosuppressive therapy.

Discordance among commercially available diagnostics for latent tuberculosis infection

RATIONALE

There is uncertainty regarding how to interpret discordance between tests for latent tuberculosis infection.

OBJECTIVES

The objective of this study was to assess discordance between commercially available tests for latent tuberculosis in a low-prevalence population, including the impact of nontuberculous mycobacteria.

METHODS

This was a cross-sectional comparison study among 2,017 military recruits at Fort Jackson, South Carolina, from April to June 2009. Several tests were performed simultaneously with a risk factor questionnaire, including (1) QuantiFERON-TB Gold In-Tube test, (2) T-SPOT.TB test, (3) tuberculin skin test, and (4) Battey skin test using purified protein derivative from the Battey bacillus.

MEASUREMENTS AND MAIN RESULTS

In this low-prevalence population, the specificities of the three commercially available diagnostic tests were not significantly different. Of the 88 subjects with a positive test, only 10 (11.4%) were positive to all three tests; 20 (22.7%) were positive to at least two tests. Bacille Calmette-Guérin vaccination, tuberculosis prevalence in country of birth, and Battey skin test reaction size were associated with tuberculin skin test-positive, IFN-γ release assay-negative test discordance. Increasing agreement between the three tests was associated with epidemiologic criteria indicating risk of infection and with quantitative test results.

CONCLUSIONS

For most positive results the three tests identified different people, suggesting that in low-prevalence populations most discordant results are caused by false-positives. False-positive tuberculin skin test reactions associated with reactivity to nontuberculous mycobacteria and bacille Calmette-Guérin vaccination may account for a proportion of test discordance observed.

Impact of targeted testing for latent tuberculosis infection using commercially available diagnostics

BACKGROUND

The interferon-γ release assays (IGRAs) are increasingly being used as an alternative to the tuberculin skin test (TST). Although IGRAs may have better specificity and certain logistic advantages to the TST, their use may contribute to overtesting of low-prevalence populations if testing is not targeted. The objective of this study was to evaluate the accuracy of a risk factor questionnaire in predicting a positive test result for latent tuberculosis infection using the 3 commercially available diagnostics.

METHODS

A cross-sectional comparison study was performed among recruits undergoing Army basic training at Fort Jackson, South Carolina, from April through June 2009. The tests performed included: (1) a risk factor questionnaire; (2) the QuantiFERON Gold In-Tube test (Cellestis Limited, Carnegie, Victoria, Australia); (3) the T-SPOT.TB test (Oxford Immunotec Limited, Abingdon, United Kingdom); and (4) the TST (Sanofi Pasteur Ltd., Toronto, Ontario, Canada). Prediction models used logistic regression to identify factors associated with positive test results. RFQ prediction models were developed independently for each test.

RESULTS

Use of a 4-variable model resulted in 79% sensitivity, 92% specificity, and a c statistic of 0.871 in predicting a positive TST result. Targeted testing using these risk factors would reduce testing by >90%. Models predicting IGRA outcomes had similar specificities as the skin test but had lower sensitivities and c statistics.

CONCLUSIONS

As with the TST, testing with IGRAs will result in false-positive results if the IGRAs are used in low-prevalence populations. Regardless of the test used, targeted testing is critical in reducing unnecessary testing and treatment.

CLINICAL TRIAL REGISTRATION

NCT00804713.

Tuberculosis: evidence review for newly arriving immigrants and refugees

BACKGROUND

The foreign-born population bears a disproportionate health burden from tuberculosis, with a rate of active tuberculosis 20 times that of the non-Aboriginal Canadian-born population, and could therefore benefit from tuberculosis screening programs. We reviewed evidence to determine the burden of tuberculosis in immigrant populations, to assess the effectiveness of screening and treatment programs for latent tuberculosis infection, and to identify potential interventions to improve effectiveness.

METHODS

We performed a systematic search for evidence of the burden of tuberculosis in immigrant populations and the benefits and harms, applicability, clinical considerations, and implementation issues of screening and treatment programs for latent tuberculosis infection in the general and immigrant populations. The quality of this evidence was assessed and ranked using the GRADE approach (Grading of Recommendations Assessment, Development and Evaluation).

RESULTS

Chemoprophylaxis with isoniazid is highly efficacious in decreasing the development of active tuberculosis in people with latent tuberculosis infection who adhere to treatment. Monitoring for hepatotoxicity is required at all ages, but close monitoring is required in those 50 years of age and older. Adherence to screening and treatment for latent tuberculosis infection is poor, but it can be increased if care is delivered in a culturally sensitive manner.

INTERPRETATION

Immigrant populations have high rates of active tuberculosis that could be decreased by screening for and treating latent tuberculosis infection. Several patient, provider and infrastructure barriers, poor diagnostic tests, and the long treatment course, however, limit effectiveness of current programs. Novel approaches that educate and engage patients, their communities and primary care practitioners might improve the effectiveness of these programs.

Pediatric travelers visiting friends and relatives (VFR) abroad: illnesses, barriers and pre-travel recommendations

Global mobility has shown a steady rise in recent years, with increased immigration and international travel. The VFR traveler is a traveler whose primary purpose of travel is to visit friends and relatives (VFR), where there is a gradient of risk between home and destination. Children are more likely to be VFR travelers than adults. Pediatric VFR travelers have higher risks for certain infectious travel-related illnesses and face multiple barriers in receiving comprehensive pre-travel care. This review focuses on the current state of knowledge of the pediatric VFR traveler, including epidemiological risks, barriers to adequate pre-travel services, and specific recommendations for disease prevention.

Comparison of mantoux and tine tuberculin skin tests in BCG-vaccinated children investigated for tuberculosis

BACKGROUND

Tuberculin skin tests (TSTs) are long-established screening methods for tuberculosis (TB). We aimed to compare agreement between the intradermal Mantoux and multipuncture percutaneous Tine methods and to quantify risk factors for a positive test result.

METHODOLOGY/PRINCIPAL FINDINGS

1512 South African children younger than 5 years of age who were investigated for tuberculosis (TB) during a Bacille Calmette Guerin (BCG) trial were included in this analysis. Children underwent both Mantoux and Tine tests. A positive test was defined as Mantoux >or=15 mm or Tine >or= Grade 3 for the binary comparison. Agreement was evaluated using kappa (binary) and weighted kappa (hierarchical). Multivariate regression models identified independent risk factors for TST positivity. The Mantoux test was positive in 430 children (28.4%) and the Tine test in 496 children (32.8%, p<0.0001), with observed binary agreement 87.3% (kappa 0.70) and hierarchical agreement 85.0% (weighted kappa 0.66). Among 173 children culture-positive for Mycobacterium tuberculosis, Mantoux was positive in 49.1% and Tine in 54.9%, p<0.0001 (kappa 0.70). Evidence of digit preference was noted for Mantoux readings at 5 mm threshold intervals. After adjustment for confounders, a positive culture, suggestive chest radiograph, and proximity of TB contact were risk factors for a positive test using both TST methods. There were no independent associations between ethnicity, gender, age, or over-crowding, and TST result.

CONCLUSIONS/SIGNIFICANCE

The Tine test demonstrated a higher positive test rate than the Mantoux, with substantial agreement between TST methods among young BCG-vaccinated children. TB disease and exposure factors, but not demographic variables, were independent risk factors for a positive result using either test method. These findings suggest that the Tine might be a useful screening tool for childhood TB in resource-limited countries.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

To BCG or not to BCG? Preventing travel-associated tuberculosis in children

With the rise in travel to countries with a high prevalence of tuberculosis (TB), the risk of travel-associated TB is of increasing concern. However, the use of Bacille Calmette-Guérin (BCG) vaccine for the prevention of travel-associated TB is a neglected area. We review and discuss national and international recommendations and guidelines for the prevention of travel-associated TB in children. Three children who developed travel-associated TB disease are described to illustrate that current recommendations, and in particular the use of pre-travel BCG immunisation, are inconsistent and controversial. The wide variation in recommendations reflects the paucity of data on the effectiveness of BCG immunisation and other preventive strategies in this setting. Until evidence-based guidelines can be produced, we believe that a low threshold for recommending BCG immunisation for travelling children is the safest strategy. A practical approach to deciding which children should be immunised with BCG prior to travel is presented.

Proposed management of childhood tuberculosis in low-incidence countries

The incidence of childhood tuberculosis continues to decline in central Europe, but due to migration from high incidence countries paediatricians will still be confronted with it. The management of childhood tuberculosis in low-incidence, high-income countries differs from most high-incidence countries. The primary measures for preventing the transmission of tuberculosis to children are the detection of adult source cases, detection of latent TB infection (LTBI) in children by history, tuberculin skin testing and, if necessary and recommended, interferon-gamma release assays. Children with LTBI should receive preventive therapy. The inclusion of tuberculosis in the differential diagnosis of unclear pulmonary and extrapulmonary disease remains important, and tuberculosis has to be managed according to international standards.

Tuberculosis screening of travelers to higher-incidence countries: a cost-effectiveness analysis

Background

Travelers to countries with high tuberculosis incidence can acquire infection during travel. We sought to compare four screening interventions for travelers from low-incidence countries, who visit countries with varying tuberculosis incidence.

Methods

Decision analysis model: We considered hypothetical cohorts of 1,000 travelers, 21 years old, visiting Mexico, the Dominican Republic, or Haiti for three months. Travelers departed from and returned to the United States or Canada; they were born in the United States, Canada, or the destination countries. The time horizon was 20 years, with 3% annual discounting of future costs and outcomes. The analysis was conducted from the health care system perspective. Screening involved tuberculin skin testing (post-travel in three strategies, with baseline pre-travel tests in two), or chest radiography post-travel (one strategy). Returning travelers with tuberculin conversion (one strategy) or other evidence of latent tuberculosis (three strategies) were offered treatment. The main outcome was cost (in 2005 US dollars) per tuberculosis case prevented.

Results

For all travelers, a single post-trip tuberculin test was most cost-effective. The associated cost estimate per case prevented ranged from $21,406 for Haitian-born travelers to Haiti, to $161,196 for US-born travelers to Mexico. In all sensitivity analyses, the single post-trip tuberculin test remained most cost-effective. For US-born travelers to Haiti, this strategy was associated with cost savings for trips over 22 months. Screening was more cost-effective with increasing trip duration and infection risk, and less so with poorer treatment adherence.

Conclusion

A single post-trip tuberculin skin test was the most cost-effective strategy considered, for travelers from the United States or Canada. The analysis did not evaluate the use of interferon-gamma release assays, which would be most relevant for travelers who received BCG vaccination after infancy, as in many European countries. Screening decisions should reflect duration of travel, tuberculosis incidence, and commitment to treat latent infection.

Antimicrobial prevention and therapy for travelers' infection

International journeys are increasing and more than 70 million people from industrialized countries cross the borders of tropical countries every year. More than 50% of them will suffer from some form of infectious illness, ranging from mild travelers' diarrhea to severe dengue fever to fatal malaria, with a wide spectrum of microbiological entities. Travel-related respiratory infections, including TB, and sexually transmitted infections are also increasingly reported. Awareness of travel-related risk is not always adequate among international travelers. Specific training on travel medicine-related issues, as well as better diagnostic facilities for imported diseases, is crucial for physicians and nurses in industrialized countries.

Immunisation of the travelling child

As a direct consequence of the current increase in international mobility, a significant increase in family travel is occurring. Protection against vaccine preventable diseases in the travelling child plays a key role both from an individual and a public health perspective: pre-travel immunisation protects travelling children and, at the same time, prevents the importation of pathogens that can spread throughout the community. Children immunisation presents unique challenges in travel medicine practice: some vaccines cannot be given below a definite age for several reasons and altering the standard schedule of routine vaccines is sometimes needed to ensure early protection. Furthermore, the risk for some travel-related diseases is higher among children. The aim of this review is to analyse the main epidemiological and clinical aspects relevant to immunisation of travelling children and to provide travel medicine practitioners with a practical approach to this issue.

Cost-effectiveness of alternative strategies for tuberculosis screening before kindergarten entry

OBJECTIVE

We undertook a decision analysis to evaluate the economic and health effects and incremental cost-effectiveness of using targeted tuberculin skin testing, compared with universal screening or no screening, before kindergarten.

METHODS

We constructed a decision tree to determine the costs and clinical outcomes of using targeted testing compared with universal screening or no screening. Baseline estimates for input parameters were taken from the medical literature and from California health jurisdiction data. Sensitivity analyses were performed to determine plausible ranges of associated outcomes and costs. We surveyed California health jurisdictions to determine the prevalence of mandatory universal tuberculin skin testing.

RESULTS

In our base-case scenario, the cost to prevent an additional case of tuberculosis by using targeted testing, compared with no screening, was $524,897. The cost to prevent an additional case by using universal screening, compared with targeted testing, was $671,398. The incremental cost of preventing a case through screening remained above $100,000 unless the prevalence of tuberculin skin testing positivity increased to >10%. More than 51% of children entering kindergarten in California live where tuberculin skin testing is mandatory.

CONCLUSIONS

The cost to prevent a case of tuberculosis by using either universal screening or targeted testing of kindergarteners is high. If targeted testing replaced universal tuberculin skin testing in California, then $1.27 million savings per year would be generated for more cost-effective strategies to prevent tuberculosis. Improving the positive predictive value of the risk factor tool or applying it to groups with higher prevalence of latent tuberculosis would make its use more cost-effective. Universal tuberculin skin testing should be discontinued, and targeted testing should be considered only when the prevalence of risk factor positivity and the prevalence of tuberculin skin testing positivity among risk factor-positive individuals are high enough to meet acceptable thresholds for cost-effectiveness.

Contact investigation and genotyping to identify tuberculosis transmission to children

BACKGROUND

Tuberculosis (TB) in young children is an indicator of ongoing community transmission. We examined contact investigations related to pediatric TB, yield for source case identifications and genotypes for relevant Mycobacterium tuberculosis isolates in a low-incidence setting.

METHODS

We reviewed public health data for all patients with TB aged <18 years reported to Montreal authorities during 1996 to 2000. M. tuberculosis isolates from patients of all ages were subjected to IS6110-based genotyping, supplemented by spoligotyping, to compare isolates from children and adults during the same years.

RESULTS

Sixty-six patients aged <18 years were diagnosed with active TB from 1996 to 2000. Mean age was 11.1 years (standard deviation 6.7 years). Twenty-five children (38%) were Canadian-born, all with at least one foreign-born parent. Nineteen children were diagnosed after contact investigations of known adult cases; 8 underwent no contact investigation. For the remaining 39 children, a total of 616 contacts were identified. The median number of contacts per child was 9 (interquartile range, 6-10). Four hundred eighty-one contacts (78%) underwent tuberculin testing; 188 (39%) were reactors and 186 (39%) began treatment of latent TB. Investigations uncovered 4 probable source cases, all involving parents or other relatives. M. tuberculosis genotyping for 38 children identified up to 14 additional possible source cases; in only one was a possible epidemiologic link evident from public health records.

CONCLUSIONS

Among largely foreign-born children with active TB, contact investigations were extensive and often identified latent tuberculosis infection--but rarely source cases. However, genotyping suggested substantial, previously unrecognized transmission to children despite low overall incidence.

Tuberculin skin testing in children

In 1996, the American Academy of Pediatrics (AAP) recommended targeted tuberculin skin testing (TST) of children while discouraging routine TST of children without risk factors for tuberculosis (TB). Recent studies have provided evidence in support of the targeted TST and recommendations that favor risk assessment over universal screening with TST. While evidence for targeted TB testing exists and benefits of screening programs are clear, administrative logistics could be a greater issue. The challenge for public health and school officials is to develop a screening program that avoids stigmatization of the at-risk group. Until then, pediatric healthcare providers will continue to have a key role in identifying children at risk for latent TB infection by using the AAP-endorsed risk-assessment questionnaire and should screen children with TST only when >1 risk factor is present.

Family travel: An overview

Paediatric travel medicine involves the education of parents about the numerous health and safety issues related to traveling with infants and young children--whether overseas or a weekend at a local lake. It includes providing children with vaccines and medications, giving telephone advice to parents while they are traveling, and treating children should they come home ill. Practitioners must be knowledgeable about such varied topics like avoiding diarrhoea, infant safety seats for air travel, altitude sickness, sun exposure, waterfront safety, insect protection, dealing with hot and cold environments, and at what age it is safe to begin scuba diving, to name just a very few. Practitioners must also know when adult recommendations can--and cannot--be adapted for children; that vaccine doses, needle size, and injection site may vary with the size of the child; and the answers to hundreds of everyday questions such as how to administer an essential but bitter tasting medication to an uncooperative child--and what to do when the child refuses to take the medication or vomits it.

Illness in returned travelers and immigrants/refugees: the 6-year experience of two Australian infectious diseases units

BACKGROUND

Data comparing returned travelers and immigrants/refugees managed in a hospital setting is lacking.

METHODS

We prospectively collected data on 1,106 patients with an illness likely acquired overseas who presented to two hospital-based Australian infectious diseases units over a 6-year period.

RESULTS

Eighty-three percent of patients were travelers and 17% immigrants/refugees. In travelers, malaria (19%), gastroenteritis/diarrhea (15%), and upper respiratory tract infection (URTI) (7%) were the most common diagnoses. When compared with immigrants/refugees, travelers were significantly more likely to be diagnosed with gastroenteritis/diarrhea [odds ratio (OR) 8], malaria (OR 7), pneumonia (OR 6), URTI (OR 3), skin infection, dengue fever, typhoid/paratyphoid fever, influenza, and rickettsial disease. They were significantly less likely to be diagnosed with leprosy (OR 0.03), chronic hepatitis (OR 0.04), tuberculosis (OR 0.05), schistosomiasis (OR 0.3), and helminthic infection (OR 0.3). In addition, travelers were more likely to present within 1 month of entry into Australia (OR 96), and have fever (OR 8), skin (OR 6), gastrointestinal (OR 5), or neurological symptoms (OR 5) but were less likely to be asymptomatic (OR 0.1) or have anaemia (OR 0.4) or eosinophilia (OR 0.3). Diseases in travelers were more likely to have been acquired via a vector (OR 13) or food and water (OR 4), and less likely to have been acquired via the respiratory (OR 0.2) or skin (OR 0.6) routes. We also found that travel destination and classification of traveler can significantly influence the likelihood of a specific diagnosis in travelers. Six percent of travelers developed a potentially vaccine-preventable disease, with failure to vaccinate occurring in 31% of these cases in the pretravel medical consultation.

CONCLUSIONS

There are important differences in the spectrum of illness, clinical features, and mode of disease transmission between returned travelers and immigrants/refugees presenting to hospital-based Australian infectious diseases units with an illness acquired overseas.

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

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

Facteurs de risque de tuberculose chez l'enfant

In order to better target children who should be screened for tuberculosis and to tailor treatment according to risk a good knowledge of the risk factors for latent tuberculosis infection and progression to disease is needed. Risk of infection is strongly related to number and duration of exposure and is particularly high when contact happens at home. Host factors like a young age or chronic underlying disease seem to favor progression to disease but do not increase infection rate. Some M. tuberculosis strains seem to be more easily transmissible. An adaptation of the criteria for a positive tuberculin skin test according to risk may help to increase the positive and negative predictive values of the test. When the risk of progression to disease is high a prophylactic treatment may be considered.

Tuberculosis in children

The epidemiology of pediatric tuberculosis (TB) is shaped by risk factors such as age, race, immigration, poverty, overcrowding, and HIV/AIDS. Once infected, young children are at increased risk of TB disease and progression to extrapulmonary disease. Primary disease and its complications are more common in children than in adults, leading to differences in clinical and radiographic manifestations. Difficulties in diagnosing children stem from the low yield of mycobacteriology cultures and the subsequent reliance on clinical case definitions. Inadequately treated TB infection and TB disease in children today is the future source of disease in adults.