Serosurvey of anti-treponema pallidum (syphilis), anti-hepatitis C virus and anti-HIV antibodies in homeless persons of São Paulo city, southeastern Brazil Laís Giuliani Felipetto; Pedro Irineu Teider-Junior; Felipe Fortino Verdan da Silva; Anahi Chechia do Couto; Louise Bach Kmetiuk; Camila Marinelli Martins; Leila Sabrina Ullmann; Jorge Timenetsky; Andrea Pires dos Santos; Alexander Welker Biondo;