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

Abstract

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 ≥10 mm that was ≥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.