1Epidemiology Laboratory, Istituto Superiore di Santà, Rome, Liver Unit “S Giacomo” Hospital, Rome, Italy
2Chair of Gastroenterology, Internal Medicine Institute, University of Palermo, Italy
3Department of Hygiene and Microbiology, University of Palermo, Italy
4Department of Internal Medicine, Cardioangiology and Hepatology, University of Bologna, Italy
5Institute of Internal Diseases, Chair of Internal Medicine, University of Verona, Italy
6Institute of Infectious Diseases, 2nd University, Naples, Italy
7Department of Alimentary Sciences, University of Naples “Federico 11”, Italy
8Department of Gastroenterology, Molinette Hospital, Turin, Italy
9Department of Internal Medicine, University of Florence, Italy