Tuberculosis contact investigations: outcomes in selected areas of the United States, 1999.

SETTING: Twenty-nine United States jurisdictions. OBJECTIVE: To determine yields of tuberculosis (TB) contact investigations. METHODS: Health departments within the jurisdictions reported counts and outcomes from routine contact investigations for cases reported in 1999. RESULTS: The 29 jurisdictions reported 9199 TB cases, 51.9% of the US and Puerto Rico 1999 total, and listed 67585 contacts. While 571 (10.6%) of 5405 pulmonary cases confirmed by sputum bacteriology had no contacts listed, 13904 contacts were listed for other cases that were unlikely to be contagious. Diagnostic evaluation was completed for 56100 contacts (83.0%), with 561 TB cases found. Of 13083 contacts found to have latent TB infection, 5746 (44.5%) completed treatment to prevent TB. Loss to follow-up and self-discontinuation of treatment accounted for 70% of reasons why treatment was not completed. CONCLUSION: Contact investigations capture substantial numbers of TB cases and latent TB infections, but the impact on prevention is limited by the poor treatment rates for infected contacts. Contacts should be sought for each potentially contagious TB case; why so many contacts are sought for cases who are unlikely to be contagious needs to be determined.

Using DNA fingerprinting to detect transmission of Mycobacterium tuberculosis among AIDS patients in two health-care facilities in Puerto Rico.

BACKGROUND: Fourteen cases of tuberculosis (TB) in Puerto Rico, diagnosed from April 1993 to April 1995, had the same DNA fingerprint, documenting disease caused by the same strain of Mycobacterium tuberculosis. The 14 cases were retrospectively investigated for epidemiologic links. METHODS: Records were reviewed and staffs of the TB program, hospital/clinic, and AIDS residential facilities were interviewed. RESULTS: Half of the AIDS cases were epidemiologically related, providing evidence of TB transmission in an emergency department, an AIDS inpatient ward, and an AIDS residential facility. DNA fingerprinting allowed detection of M tuberculosis transmission, but contact investigators could have documented it sooner. Factors contributing to transmission included delayed diagnosis, prolonged infectiousness, inadequate discharge planning and infection control procedures, and poor communication between health-care facilities. CONCLUSIONS: The numbers of AIDS residential facilities are increasing and must understand proper monitoring of TB patients and infection control measures that prevent transmissions.