1. Epidemiology Unit, Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Rome, Italy
2. Virology Unit, Institut Pasteur of Madagascar, Antananarivo, Madagascar
3. Department of Biomedical and Clinical Sciences “Luigi Sacco”, Infectious Diseases and Immunopathology Section, ‘L. Sacco’ Hospital, University of Milan, Milan, Italy
4. Clinical Pathology and Microbiology Laboratory, University Hospital Campus Bio-Medico of Rome, Rome, Italy
5. Public Health and Infectious Diseases, Sapienza University, Rome, Italy
6. University Hospital Campus Bio-Medico, Rome, Italy
7. Digestive Disease Unit of Campus Bio Medico University of Rome, Rome, Italy