Thanks, Alessandra; I was hoping to hear this! I travel a lot in Italy on trains (but never by boat - though I hope to one day) and I wanted to see just how rare something like this is! (Put my mind at ease - phew!).
A few years ago, after a wonderful three weeks in Italy, we took an overnight train (1st class cabin with bunk beds) from Naples to Milan just before a flight back to Los Angeles. It was a traumatic 2 days. I was covered with flea bites from the train, and itched terribly the whole flight home.
THEN, after exiting customs in LA, I sat outside on the wide edge of a cement planter in front of the Intl. terminal at LAX with our luggage while Brad went to get the rental car to drive home. I turned around, and at least 100 tiny mice were in the planter walking toward me. It was like a Hitchcock movie! You never saw anyone scream and run so fast pushing a heavy luggage cart toward the curb! Re-entry can be tough! I haven't seen fleas or rodents again, and it would take quite a bit to keep me from traveling in Italy (however, I do prefer the rental car route!).
Hmm... so I wonder if it's the overnight thing. I've never done an overnight trip - just long 6-7 hour train rides sitting upright in a seat (I definitely did get a bad sore throat infection after riding a train once) but I guess it's like bed bugs - you never know - and esp. in the heat of summer. Ick.
I laughed at loud at the images you conjured up with your story. My lord, girl, you had quite a trip that time! (Sorry, but it's funny if it's someone else's experience, not one's own).