A. Ivanov1*, B. Petrov2, C. Dimitrov3, A. Yaneva4
Medical University of Plovdiv, Bulgaria:
1-Department of Pediatrics and Medical Genetics, Medical Faculty;
2-Department of Pediatric Dentistry, Dental Faculty;
3-Department of Microbiology and Immunology, Faculty of Pharmacy;
4-Department of Hygiene and Ecomedicine, Faculty of Public Health;
*St. George University Hospital, Plovdiv, Bulgaria