[1] Univ Bologna, Operat Unit Clin Microbiol, DIMES, Lab Virol,St Orsola Malpighi Gen Hosp, IT-40138 Bologna, Italy
[2] Univ Bologna, Operat Unit Clin Microbiol, Virol Lab, St Orsola Malpighi Gen Hosp, IT-40138 Bologna, Italy
[3] Univ Bologna, Operat Unit Obstet & Prenatal Med, DIMEC, St Orsola Malpighi Gen Hosp, IT-40138 Bologna, Italy