Star Trek Universe Continuity
In this episode, it is revealed that Curzon Dax was Commander Sisko's mentor at Starfleet, thus creating a continuity that completely breaks from the introduction of the Trill in the Star Trek: The Next Generation
episode "The Host
". In "The Host", Counsellor Deanna Troi states that the Federation knows so little about the Trill. Before the events of "The Host", the Chief Medical Officer of the Enterprise
, Doctor Beverly Crusher, had no knowledge about the relationship between the Trill and its host. It is impossible for the Trill to have entered Starfleet without the Federation discovering their symbiotic relationship.