1. Department of Public Health and Infectious Diseases, “Sapienza” University of Rome, Rome, Italy.
2. Department of Microbiology and Immunology, Faculty of Medicine, University of Niš, Niš, Serbia.
3. Center of Microbiology and Parasitology, Public Health Institute Niš, Niš, Serbia.
4. Department of Medical Statistics, Faculty of Medicine, University of Niš, Niš, Serbia.
5. Clinic of Ophthalmology, Clinical Center of Niš, Nis, Serbia.