[Tuberculosis among health care workers in Okinawa Prefecture].

In health care setting, transmission of M. tuberculosis (TB) is considerable risk not only to patients but to health care workers (HCWs). The total number of registered TB cases in Okinawa prefecture was 1,202 in 1993-1995 (incidence rate 28.3 per 100,000 in 1995) and that of HCWs was 23. Using data from TB registration system, relative risk of tuberculous disease of nurses was estimated to be 2.3 higher than general population. Nosocomial transmission of TB to HCWs in a general hospital was occurred in 1993. After 2 nurses in the same ward were diagnosed as active pulmonary TB by routine screening chest X-ray, a contact investigation was performed in their family, friends and the ward staffs. On the result of initial evaluation of PPD test, 22 of 26 HCWs were suspected to be infected and preventive therapy with isoniazid were given to 16 HCWs. Follow-up chest radiographs for 3 years revealed 5 HCWs were active TB. According to RFLP analysis of M. tuberculosis isolates, 3 HCWs and 1 patient had identical RFLP pattern to 65-year-old female SLE patient, who was admitted for fever in Nov. 1993 and was diagnosed as miliary tuberculosis after 2 weeks admission. As she had no cough and sputum, the infectiousness of the case was suspected to be increased by cough-inducing procedure. The following TB infection control measures were conducted in the hospital; (1) Education and training to all HCWs for early identification of TB patient and adequate treatment (2) Surveillance and reporting system of TB patient from laboratory and ward to infection-control committee (3) Introduction of PPD test program for HCWs (4) Use of HEPA masks as personal respiratory protection. We need further evaluation of engineering controls e.g. ventilation and isolation room.