1. Department of Clinical and Experimental Medicine, University of Florence , 50134 Florence , Italy
2. Regional Referral Center for Tropical Diseases , Infectious and Tropical Diseases Unit, , 50134 Florence , Italy
3. Careggi University Hospital , Infectious and Tropical Diseases Unit, , 50134 Florence , Italy
4. Infectious and Tropical Diseases Unit, Careggi University Hospital , 50134 Florence , Italy
5. Microbiology and Virology Unit, Careggi University Hospital , 50134 Florence , Italy