Background: In early 2001 there were indications that tuberculosis (TB) was increasingly becoming aproblem among drug addicts and homeless persons in Rotterdam, after a periodical screening wasdiscontinued in 1997. A contact investigation around a homeless drug addicted man in Rotterdamwith infectious pulmonary TB is described. Contact investigation: A total of 507 drug addicts, homelesspersons, and staff of facilities for these risk groups were examined with tuberculin skin testing (TST) andche ...