Screening for tuberculosis upon admission to shelters and free-meal services

Background: The homeless are at very high risk of suffering tuberculosis (T B). The aims of this study were to determine the prevalence and risk factor s for tuberculosis infection and disease among the homeless in Barcelona an d to evaluate the roles of case finding and contact investigation. Methods: Observational prevalence study carried out between 1997 and 1998. Particip ants: 447 homeless patients (394 men and 53 women) were evaluated before ad mission to shelters and free-meal services. At the same time, 48 co-residen ts with smear-positive TB patients in 2 long-term shelters were evaluated t oo. A chest X-ray and Tuberculin Skin Test were performed on all subjects. Sputum smears were processed by the Ziehl-Neelsen and Lowenstein-Jensen pro cedures in patients with radiographic findings consistent with pulmonary TB . Results: Of the 447 homeless examined, 335 (75%) were infected with Mycob acterium tuberculosis. Active pulmonary TB was diagnosed in five persons (1 .11%), and 62 (13.8%) had radiographic evidence of inactive pulmonary TB. T uberculosis infection was associated with age and smoking, but not with sex or alcohol abuse. No significant differences in infection rates were found between the main group and 48 homeless co-residents of smear-positive subj ects. Only 16.9% of the homeless with active TB in Barcelona in the same pe riod were diagnosed through active case-finding, the remainder being mainly detected in hospitals (69.8%) and other several centres (13.3%). Conclusio ns: Homeless individuals have a very high risk of TB infection and disease and contact investigation requires specific methods for them. Programmes of screening and supervised treatment should be ensured in this group.