1. Regional Directorate of Sicily, Maritime Health Authority, Ministry of Health, 90133 Palermo, Italy
2. Department of Medicine and Surgery, School of Hygiene and Preventive Medicine, University of Perugia, 06123 Perugia, Italy
3. Directorate General of Health Prevention, Ministry of Health, 00100 Rome, Italy
4. National Committee, Italian Red Cross, 00100 Rome, Italy