1. Laboratory of Microbiology and Virology, National Institute of Gastroenterology “Saverio de Bellis,” Research Hospital, Bari, Italy.
2. Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari “Aldo Moro,” Bari, Italy.
3. Department of Gastroenterology, National Institute of Gastroenterology “Saverio de Bellis,” Research Hospital, Bari, Italy.
4. Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata, Sezione di Putignano, Bari, Italy.