The fact that ebola can be sexually transmitted is irrelevant here, because Hickox never had ebola.
At the time of the quarantine, that was unknown and NOT PROVEN.
She failed to abide by the self quarantine, and acted as if the rules did not apply to her.
And at that point, nobody knew if she did or didn't.
http://www.latimes.com/nation/la-na-1012-ebola-fever-20141012-story.html
Not everyone exhibits fever under ebola infection.