Introduction To reach pre-elimination levels of tuberculosis (TB) incidence in the Netherlands, prevention of TB among immigrants through diagnosis and treatment of latent TB infection (LTBI) is needed. We studied the feasibility of a LTBI screening and treatment program among newly arriving immigrants for national implementation. Methods We used mixed methods to evaluate the implementation of LTBI screening and treatment in five Public Health Services (PHS) among immigrants from countries with a TB incidence >50/100,000 population. We used Poisson regression models with robust variance estimators to assess factors associated with LTBI diagnosis and LTBI treatment initiation and reported reasons for not initiating or completing LTBI treatment. We interviewed five PHS teams using a semi-structured method to identify enhancing and impeding factors for LTBI screening and treatment. Results We screened 566 immigrants; 94 (17%) were diagnosed with LTBI, of whom 49 (52%) initiated and 34 (69%) completed LTBI treatment. LTBI diagnosis was associated with male gender, higher age group, higher TB incidence in the country of origin and lower level of education. Treatment initiation was associated with PHS (ranging from 29% to 86%), lower age group, longer intended duration of stay in the Netherlands, and lower level of education. According to TB physicians, clients and their consulted physicians in the home country lacked awareness about benefits of LTBI treatment. Furthermore, TB physicians questioned the individual and public health benefit of clients who return to their country of origin within the foreseeable future. Conclusions Doubt of physicians in both host country and country of origin about individual and public health benefits of LTBI screening and treatment of immigrants hampered treatment initiation: the high initiation proportion in one PHS shows that if TB physicians are committed, the LTBI treatment uptake can be higher.

In 2005, a 24-year-old man with Crohn disease who had been treated with infliximab for several months was exposed to an individual with smear-positive tuberculosis. Soon after exposure, he complained of malaise, dry cough, and weight loss. Despite normal chest radiograph findings and negative tuberculin skin test results, tuberculosis was considered to be the most likely diagnosis. The results of a whole-blood assay for detection of interferon- gamma production in response to Mycobacterium tuberculosis-specific antigen were positive. Acid-fast staining and polymerase chain reaction of bronchoalveolar lavage fluid samples had negative results, but M. tuberculosis was cultured. After the initiation of 4 antitubercular drugs and the discontinuation of infliximab therapy, the patient developed an immune reconstitution syndrome accompanied by enlarged mediastinal lymph nodes and multiple intrapulmonary miliary lesions. This case of de novo tuberculosis during anti-tumor necrosis factor alpha treatment illustrates the uncharacteristic presentation of the disease and the elusiveness of the diagnosis, as well as the fact that discontinuation of anti-tumor necrosis factor alpha treatment can be accompanied by an immune reconstitution syndrome similar to that observed in human immunodeficiency virus-infected individuals with tuberculosis.

This study aimed to estimate the risk of progression to active tuberculosis (TB) within 2 yrs after entry in newly arriving immigrants who were screened with the QuantiFERON®-TB Gold In-Tube assay (QFT-GIT; Cellestis, Carnegie, Australia).In a case–base design, we determined the prevalence QFT-GIT-positive subjects among a representative sample of immigrants aged ≥18 yrs who arrived between April 2009 and March 2011 (the base cohort). Active TB patients (cases) within 2 yrs post-arrival in 2005, 2006 or 2007 were extracted from the Netherlands Tuberculosis Register. The risk of progression to active TB was estimated using Bayesian analyses to adjust for the sensitivity of QFT-GIT.Among the base cohort, 20% of 1,468 immigrants were QFT-GIT positive. Stratified by TB incidence in the person's country of origin as low (<100 cases per 100,000 population), intermediate (100–199 cases per 100,000) or high (≥200 cases per 100,000), the risk of progression to active TB per 100,000 arriving immigrants if QFT-GIT positive (95% credibility interval) was 456 (95% CI 307–589), 590 (397–762) and 386 (259–499), respectively, compared with 18 (0–46), 38 (0–97) and 28 (0–71) if QFT-GIT negative.Screening newly arriving immigrants with QFT-GIT contributes to detecting those at high risk of subsequent TB reactivation within 2 yrs after entry, which offers opportunities for prevention by targeted interventions.

The effectiveness of contact investigations in the Netherlands can be optimised by expanding the investigation of contacts of immigrant patients.

Interferon-γ release assays (IGRAs) such as Quantiferon (QFT) that detect T-cell responses to antigens specific for Mycobacterium tuberculosis (MTB) have superior specificity to the tuberculin skin test (TST). While IGRAs are technically robust and the test result is a simple positive or negative, the interpretation nevertheless requires thorough understanding of the test's characteristics [1]. An area of debate is that of "borderline" results near the cutoff value, mentioned first in the setting of serial screening of health care workers [2]. While different authors used different ranges of test results under this denominator, borderline results were generally attributed to random assay variability [3, 4]. In reproducibility studies, conversions and reversions were often seen around the manufacturer-recommended cutoff , with the advice to "interpret such results cautiously" [5, 6].