[1] Chinese Univ Hong Kong, Prince Wales Hosp, Dept Microbiol, Fac Med, Shatin, Hong Kong, Peoples R China
[2] ANLIS Carlos G Malbran, Inst Nacl Enfermedades Infecciosas, Dept Virol, Serv Virus Oncogen, Buenos Aires, DF, Argentina
[3] Prince Wales Hosp, Dept Obstet & Gynaecol, Hong Kong, Hong Kong, Peoples R China
[4] Azienda Osped Univ Policlin P Giaccone, Sez Microbiol, Dipartimento Sci Promoz Salute, Palermo, Italy
[5] Catholic Univ Korea, Seoul St Marys Hosp, Dept Obstet & Gynecol, Seoul, South Korea