Just watched 2.7, great ep but....
Why the hell did they put "Madison Lintz" on the guest starring bit at the start??? Great way to totally ruin the surprise by knowing that at some point she was gonna be in this episode.
(Yes I am such a nerd that I read the titles, and for some reason know that actress' name)
As for the 'zombie virus,' I've always felt Ken Foree's theory explains it best-