5 Oral Medicine Unit, Faculty of Dentistry, MedOralRes, Universidad de Santiago de Compostela, Instituto de Investigación Sanitaria (IDIS), Entrerríos s/n, 15782, Galicia, Spain. mario.perez@usc.es.
6 Laboratory of Virology, Institute of Tropical Medicine of São Paulo, School of Medicine, University of São Paulo, São Paulo, 05508-000, Brazil.