1. Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
2. Department of Medical and Surgical Sciences and Advanced Technology ‘G.F. Ingrassia’, University of Catania, 95125 Catania, Italy
3. Laboratory of Clinical Virology, Medical School, University of Crete, 71003 Heraklion, Crete, Greece
4. Department of Microbiology and Immunology, Brody School of Medicine at East Carolina University, Greenville, NC 27858, USA