It's a reference to Italia and Roma constantly taking off. It's, unfortunately infectious.
Yeah, but Italia and Roma's characterizations in Ido's comic are directly based upon Hetalia, hence it's valid to wonder if this happened in Hetalia, as well.
Paaastaaa!Enemy Flagship fleet, spotted!It's the final battle.Pizza!I don't wanna fight zui!Before that, wouldn't a siesta be nice?I give up!Affirmative!The Strait of DoverBut the ships that resupplied in Italy have been infected with Italianitis.Yeah!Cruising formation 4!Let's keep our wits about us.You can give them a good whack.