User blog comment:FairyRaven/Fairy Tail Chapter 360:The White Inheritance, Review and Commentary/@comment-4643135-20131117042608/@comment-7418318-20131117082706

Don't forget that Fairy Tail only knows that Tartarus is targeting former council members because some of their members happened to be present in one such attack by chance.

Unless Fairy Tail spread the news, the other guilds only know that there was some incident in that town that left half of it poisoned by a magical desease (or however you want to call it).