1. 1 Pneumology Department, Medicine Faculty , Ovidius University of Constanta , Romania
2. 2 PhD Medicine School , Ovidius University of Constanta , Romania
3. 3 Clinical Hospital of Pneumology , Constanta , Romania
4. 4 Infectious Diseases Department, Medicine Faculty , Ovidius University of Constanta , Romania
5. 5 Occupational Department, Medicine Faculty , Carol Davila University of Medicine and Pharmacy , Bucharest , Romania
6. 6 Occupational Department , Clinical Colentina Hospital Bucharest , Romania