Diagnosis of latent tuberculosis infection in units of the tuberculosis institution
Currently detection and monitoring of latent tuberculosis infection (LTI) lead to decrease of the tuberculosis spread. Employees of anti-tuberculosis health care system are in group of risk for development of tuberculosis, and implementation of new immunological tests for timely detection of latent infection is an important task of mo­dern phthisiology. In this prospective study employees of anti-tuberculosis heath care system were examined at the age of 18 to 65 years (n=164). The comparison group consisted of healthy subjects (n=30) without acute and chronic diseases, as well as with no contact with patients with tuberculosis. To identify the LTI, immunological tests (a test with Diaskintest, a QuantiferonTBgold test, and a T-SPOT) were used. The LTI level was analyzed taking into account duration of work of the staff in conditions of TB facility and the risk of LTI infection development in various departments. According to received data, the risk of LTI development correlates with the duration of work in the anti-tuberculosis heath care system (AHS). The highest level of LTI was observed among employees that worked in the department more than five years (48.4%, RR=0.94). In different departments the level of LTI was significantly different. So the highest percentage of LTI detection was observed in surgical and therapeutic departments for the treatment of pulmonary TB patients (69.2 and 30.8%, respectively); while in departments with extrapulmonary forms of the disease and in differential diagnostic department (19.4 and 15.8%, respectively) - low levels, that identifies a high and low risk of LTI development. The obtained results allow to identify the risk of LTI in anti-tuberculosis heath care system and to approach differently to observation and implementation of preventive measures taking into account difference in the risk of infection at departments with high and low risk of LTI development.