1. Division of STD Prevention, National Center for HIV, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
2. Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts
3. Department of Pathology, University Hospital of Coimbra, Coimbra, Portugal
4. Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP) & Faculty of Medicine/H.S. João, Porto, Portugal