[1] Fdn IRCCS Policlin San Matteo, SC Microbiol & Virol, Pavia, Italy
[2] Univ Pavia, Dipartimento Biol & Biotecnol L Spallanzani, Pavia, Italy
[3] Univ Milan, Dipartimento Sci Biomed & Cliniche L Sacco, Ctr Ric Pediat Romeo & Enrica Invernizzi, Milan, Italy
[4] Ist Zooprofilatt Sperimentale Lombardia & Emilia, Unita Anal Rischio, Parma, Italy