Well as the UNSC, the only things that can't be infected are the Infinity and the Infinity. Also infection is carried out by spores. Also infection is Instant.
I got a new baby bunny rabbit, he's mostly white with small patches of brown fur with blue eyes. I named him Thumper! - Named after the Bambi Thumper character.
I don't know what it is about Sakura Trick that makes it a beautifully constructed story but all I know is, it's romantic and really cute. So that's what matters right?