TB in a Low-Incidence Country: Differences Between New Immigrants, Foreign-Born Residents and Native Residents

• Published in: The American journal of medicine Vol. 120; no. 4; pp. 350 - 356
• Main Authors: Laifer, Gerd, MD, Widmer, Andreas F., MD, MS, Simcock, Mathew, MSc, Bassetti, Stefano, MD, Trampuz, Andrej, MD, Frei, Reno, MD, Tamm, Michael, MD, Battegay, Manuel, MD, Fluckiger, Ursula, MD
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.04.2007; Elsevier; Elsevier Sequoia S.A
• Subjects: Adolescent; Adult; Africa - epidemiology; Aged; Aged, 80 and over; Alcohol Drinking - epidemiology; Antitubercular Agents - therapeutic use; Asia - epidemiology; Bacterial diseases; Biological and medical sciences; Clinical presentation; Comorbidity; Comparative studies; Drug Resistance, Bacterial; Emigration and Immigration - statistics & numerical data; Epidemiology; Europe, Eastern - epidemiology; Female; Foreign-born; General aspects; Human bacterial diseases; Humans; Immigrants; Incidence; Infectious diseases; Internal Medicine; Latin America - epidemiology; Male; Mass Screening - statistics & numerical data; Medical sciences; Medical screening; Mediterranean Region - epidemiology; Middle Aged; Noncitizens; Radiology; Residence Characteristics - statistics & numerical data; Residents; Risk Factors; Screening; Switzerland - epidemiology; Tuberculosis; Tuberculosis and atypical mycobacterial infections; Tuberculosis, Pulmonary - diagnosis; Tuberculosis, Pulmonary - drug therapy; Tuberculosis, Pulmonary - ethnology; Switzerland; Europe; Europe, Eastern; Mediterranean Region; Asia; Africa; Latin America; Screening; Foreign-born; Clinical presentation; Tuberculosis; Immigrants; Residents; Infection; Human; Immigrant; Bacteriosis; Mycobacterial infection; Epidemiology; Comparative study; Incidence
• ISSN: 0002-9343; 1555-7162
• DOI: 10.1016/j.amjmed.2006.10.025

Abstract Background New immigrants and foreign-born residents add to the burden of pulmonary tuberculosis (TB) in low-incidence countries. The highest TB rates have been found among recent immigrants. Active screening programs are likely to change the clinical presentation of TB, but the extent of the difference between immigrant and resident populations has not been studied prospectively. Methods Adult new immigrants were screened upon entry to 1 of 5 immigration centers in Switzerland. Immigrants with abnormal chest radiographs were enrolled and compared in a cohort study to consecutive admitted foreign-born residents from moderate-to-high incidence countries and native residents presenting with suspected TB. Results Of 42,601 new immigrants screened, 112 had chest radiographs suspicious for TB. They were compared with foreign-born residents (n = 118) and native residents (n = 155) with suspected TB (n = 385 patients included). Active TB was confirmed in 40.5% of all patients (immigrants 38.4%, foreign-born residents 50%, native residents 34.8%). Clinical signs and symptoms of TB and laboratory markers of inflammation were significantly less common in immigrants than in the other groups with normal results in >70%. The proportion of positive results on rapid testing to detect M. tuberculosis (MTB) in 3 respiratory specimens was significantly lower in immigrants (34.9% for acid-fast staining; 55.8% for polymerase chain reaction) compared with foreign-born residents (76.2% and 89.1%, respectively) and native residents (83.3% and 90.9%, respectively). Isoniazid resistance and multi-drug resistance were more prevalent in immigrants. Conclusion New immigrants with TB detected in a screening program are often asymptomatic and have a low yield of rapid diagnostic tests but are at higher risk for resistant MTB strains. Postmigration follow-up of pulmonary infiltrates is essential in order to control TB among immigrants, even in the absence of clinical and laboratory signs of infection.