Coverage and yield of entry and follow-up screening for tuberculosis among new immigrants.

The aim of the present study was to determine the effectiveness of entry screening for tuberculosis and biannual follow-up screening among new immigrants in The Netherlands. To achieve this, the present authors analysed screening, prevalence and incidence data of 68,122 immigrants, who were followed for 29 months. Patients diagnosed within 5 months and 6-29 months after entry screening were considered to be detected at entry and during the follow-up period, respectively. Coverage of the second to fifth screening rounds was 59, 46, 36 and 34%, respectively. Yield of entry screening was 119 per 100,000 individuals, and prevalence at entry was 131 per 100,000. Average yield of follow-up screening was highest among immigrants with abnormalities on chest radiography (CXR) at entry (902 per 100,000 individuals). When excluding these, yield of follow-up screening was 9, 37 and 97 per 100,000 screenings for immigrants from countries with tuberculosis incidences of <100, 100-200 and >200 per 100,000, respectively. The incidence during follow-up in individuals with a normal CXR was 11, 58 and 145 per 100,000 person-yrs follow-up in these groups. The proportion of cases detected through screening declined per screening round from 91 to 31%. Yield of entry screening was high. Overall coverage and yield of follow-up screening was low. Follow-up screening of immigrants with a normal chest radiograph from countries with an incidence of <200 per 100,000 individuals was therefore discontinued.

HIV-related mortality among tuberculosis patients in The Netherlands, 1993-2001.

Human immunodeficiency virus (HIV) infection in tuberculosis (TB) patients in The Netherlands during the period 1993-2001 was associated with an increased risk of death (adjusted odds ratio 4.71, P < 0.002). Age and sex-standardised mortality rates among HIV-infected TB patients decreased significantly over time, from 22.9% in 1993-1995 to 11.8% in 1999-2001 (P < 0.001). No such change was observed for HIV-negative patients. The decrease in mortality is likely due to the more widespread use of highly active antiretroviral therapy (HAART).

HIV prevalence among tuberculosis patients in The Netherlands, 1993-2001: trends and risk factors.

OBJECTIVES: To describe the prevalence and predictive factors of human immunodeficiency virus (HIV) infection among tuberculosis (TB) patients in The Netherlands during the period 1993-2001. DESIGN: Data were obtained from the national surveillance register of all patients notified with TB (all forms) during the period of the study. In addition, records or discharge notes were checked of a random sample of 200 TB patients notified in 1995 and another 200 in 2001. RESULTS: Of 13 269 patients diagnosed with TB, 542 were HIV-positive (4.1%). Prevalence was 4.1% in 1993-1995, 3.8% in 1996-1998 and 4.4% in 1999-2001. The highest prevalence was observed among drug users (29.2%), homeless patients (20.1%) and patients residing illegally in the country (9.1%). Compared with the period 1993-1995, the relative risk of HIV infection in the periods 1996-1998 and 1999-2001 decreased significantly for drug using patients (P = 0.006), and increased for patients from African countries (P < 0.001). According to patient records, 29/184 (16%) had been tested for HIV in 1995 and 39/190 (21%) in 2001 (P = 0.289); 18 patients tested positive (4.8%). CONCLUSION: Although the prevalence of HIV among TB patients in The Netherlands remained stable between 1993 and 2001, the distribution of risk groups changed over this period.

Tuberculosis infection in children who are contacts of immigrant tuberculosis patients.

The present study aimed to determine what proportion of children who are in close contact with immigrant tuberculosis (TB) patients are infected with Mycobacterium tuberculosis. For 1.5 yrs, 14 municipal health services in The Netherlands collected data from all non-Dutch TB patients and their contacts. Close contacts aged < 16 yrs received a tuberculin skin test (TST). A positive TST was defined as an induration of > or = 10 mm among nonvaccinated children, and > or = 16 mm among bacille Calmette-Guérin-vaccinated children. In total, 244 patients had 359 close contacts aged < 16 yrs. Nine out of the 359 (2.5%) had TB. A TST test was given to 298 out of the 359 (83%). Of the 115 contacts of 44 extrapulmonary TB patients, three (3%) had a positive TST. Of the 186 contacts of 58 positive pulmonary TB patients, 30 (16%) had a positive TST. Contacts of sputum smear-positive patients significantly more often had a positive TST (25%), compared with the contacts of sputum smear-negative patients (7%). Children born abroad significantly more often had a positive TST (20%) than children born in The Netherlands (5%). In conclusion, the prevalence of active tuberculosis and latent tuberculosis infection among children who are close contacts of immigrant tuberculosis patients is high and warrants an expansion of contact investigation.

Tuberculosis contact investigation and DNA fingerprint surveillance in The Netherlands: 6 years' experience with nation-wide cluster feedback and cluster monitoring.

SETTING: The Netherlands, 1995-2000. OBJECTIVES: To describe the contribution of 6 years of nationwide DNA fingerprint surveillance to tuberculosis control in general and to conventional contact investigations in particular. DESIGN: All Mycobacterium tuberculosis cultures are subjected to standardised IS6110-based RFLP typing, and clustered cases are systematically reported to the regional TB services involved (cluster feedback). Standardised questionnaires are used to collect information on contact investigations and epidemiological links (epi links) at regional level. Revision of the questionnaires for the period 1997-2000 allows comparison of epi linking before and after cluster feedback. RESULTS: Among 2206 clustered cases, 462 (21%) epi links were expected before the RFLP result, whereas an additional 540 (24%) epi links were established after cluster feedback. Epi links based on documented exposure increased by 35%, from 357 to 550 (P < 0.001). Only 1% of contact investigations were extended, however, and relatively few additional persons with active or latent tuberculosis were diagnosed. Reasons for the limited impact on contact investigation outcome were 1) contact took place 1-7 years previously (51%), 2) documented contact involved a subsequent case in the cluster (21%), 3) casual contact (15.5%) and 4) different region (9%). Five per cent of epi links established by contact investigation were contradicted by RFLP data. Epi links were more frequently documented in Dutch (41%) than non-Dutch cases (19%, OR 3.0; 95%CI 1.41-1.91). Cluster monitoring permitted: 1) identification of transmission chains that could not be detected by contact investigations, 2) development and evaluation of targeted interventions, and 3) identification of professional failures and poor programme performance. CONCLUSIONS: RFLP surveillance forms the bridge between conventional contact investigation and other forms of targeted active case finding. Combining both complementary strategies in a comprehensive approach to systematic outbreak monitoring and management allows countries in the elimination phase of the disease to better target and evaluate TB control interventions.

[Delay in the diagnosis of tuberculosis]. / Vertraging bij de diagnostiek van tuberculose.

In five patients, a 46-year-old Surinamese man, a 45-year-old Dutch barkeeper, a 41-year-old woman from Eritrea, and an 18-year-old Afghan woman and her 43-year-old mother, tuberculosis was diagnosed and treated after a considerable delay. Such a late diagnosis and subsequent treatment is not uncommon for tuberculosis as the symptoms, physical examination, laboratory tests, imaging techniques and bacteriological results are often not very specific. However under certain circumstances, tuberculosis (including the extrapulmonary manifestations) should be considered at an earlier stage, especially among certain risk groups such as the homeless, drug addicts, immigrants and asylum seekers. In the five patients discussed the causes of delay were identified as: delay caused by the asymptomatic phase of the disease, the patient's delay in presenting, a delay on the part of the physician, a delay in diagnostic confirmation and a delay in the treatment.

[Limited tuberculin screening participation amongst travellers to countries with high tuberculosis incidence; reason to consider BCG vaccination for some travellers]. / Beperkte deelname aan tuberculinescreening onder reizigers naar landen met hoge tuberculose-incidentie; reden om voor sommigen BCG-vaccinatie te overwegen.

OBJECTIVE: To determine the compliance amongst Dutch travellers to high tuberculosis-incidence countries with a screening procedure involving a tuberculin skin test before and after the trip. DESIGN: Prospective study. METHOD: Nine hundred and eighty-eight tuberculin-negative Dutch people who travelled to high tuberculosis-incidence countries for 3 to 12 months were studied for their compliance with an advised screening procedure of repeat tuberculin skin testing 2 to 4 months after return. At 2 of the 4 participating health services, data were also collected on extra calls made and the pertinent time investments. RESULTS: Five hundred and ninety-nine travellers (61%) were compliant with the screening procedure. Of those for whom the data was available (n = 417), 33% (98/300) of the compliant travellers required extra calls. These took an average of 30 min per extra traveller tested as a result. Compliance varied according to health service and was better amongst travellers to Africa. In addition, non-compliance was independently associated with male sex, work being the main travel purpose, and an undecided duration of travel on departure. CONCLUSIONS: Compliance of Dutch travellers with tuberculin skin-test screening is limited, particularly if no extra calls are issued. Bacillus Calmette-Guérin vaccination appears to be preferable for travellers with undecided travel duration and persons travelling for work on a frequent basis.

Association of tuberculin sensitivity in Dutch adults with history of travel to areas of with a high incidence of tuberculosis.

International travel may be a source of introduction of tuberculosis into low-incidence countries. We assessed whether, in The Netherlands, sensitivity to tuberculin was associated with a history of travel to countries with a high incidence of tuberculosis. Immunocompetent adults with no history of Bacille Calmette-Guérin vaccination or sensitivity to tuberculin were skin-tested simultaneously with 1-tuberculin unit (TU) purified protein derivative (PPD) of Mycobacterium tuberculosis and 1-TU sensitin of Mycobacterium scrofulaceum. Tuberculin sensitivity was defined as a reaction to PPD of > or =10 mm that was > or =3 mm larger than the reaction to M. scrofulaceum sensitin. Tuberculin sensitivity was found in 7 (0.7%) of 1014 participants (95% confidence interval [CI], 0.3%-1.4%); it was independently associated with a cumulative history of >3-months' travel to high-incidence areas (odds ratio, 6.0; 95% CI, 1.2-31.2; P=.016) and increased in association with total duration of travel (P=.02). Travel to high-incidence areas increases the risk of tuberculin sensitivity and, consequently, of latent tuberculous infection. In countries with a low incidence of tuberculosis, cases of infection acquired during travel may account for a substantial proportion of new infections in the resident population.

Risk of infection with Mycobacterium tuberculosis in travellers to areas of high tuberculosis endemicity.

BACKGROUND: No data exist on risks of infection with Mycobacterium tuberculosis in travellers. We studied incidences of and risk factors for tuberculin skin-test conversion among Dutch long-term travellers to countries of high tuberculosis endemicity. METHODS: In a multicentre, prospective cohort study based in travel and tuberculosis clinics in the Netherlands, 1072 BCG-naive immunocompetent travellers to countries with an estimated annual risk of M. tuberculosis infection of at least 1% were skin tested before departure with 1 tuberculin unit purified protein derivative (PPD) of M. tuberculosis in Tween-80. Those with results less than 2 mm were retested 2-4 months after their return with simultaneous testing for cross-sensitivity to environmental mycobacteria (1 tuberculin unit PPD of M. scrofulaceum in Tween-80). M. tuberculosis infection was defined as a post-travel M. tuberculosis tuberculin skin-test result of at least 10 mm that was 3 mm or more larger than the M. scrofulaceum result. FINDINGS: Post-travel skin-test results were available for 656 (66%) of 988 individuals who were eligible for follow-up. Among these, 12 M. tuberculosis infections were identified (1.8%). The overall incidence rate was 3.5 per 1000 person-months of travel (95% CI 2.0-6.2), and 2.8 per 1000 person-months of travel (1.2-5.5) after exclusion of health-care workers. Two had active tuberculosis at the time of testing (incidence rate 0.6 per 1000 person-months of travel [0.3-2.3]). Work in patient care abroad was an independent risk factor (adjusted rate ratio 5.34, p=0.015). INTERPRETATION: The risk of M. tuberculosis infection in long-term travellers to high-endemicity countries, even if not engaged in health-care work, is substantial and of similar magnitude to the average risk for the local population. BCG vaccination or post-travel tuberculin skin-testing of high-risk travellers should be considered.