High prevalence of the simultaneous excretion of polyomaviruses JC and BK in the urine of HIV-infected patients without neurological symptoms in São Paulo, Brazil - Nali, Luiz Henrique da; Centrone, Cristiane de Campos; Urbano, Paulo Roberto Palma; Penalva-de-Oliveira, Augusto César; Vidal, Jose Ernesto; Miranda, Erique Peixoto; Pannuti, Claudio Sérgio; Fink, Maria Cristina Domingues da Silva; Chieffi, Pedro Paulo (Revista do Instituto de Medicina Tropical de São Paulo, 2012)