When running short of ideas for a Star Trek episode, a mysterious life-threatening illness was apparently the filler of choice. This one is of course different than its predecessors in symptoms, but we get the same formula.
Really, the only charms of the episode lie in Kira, Odo and Quark. Kira reminds us that she is willing to take extreme measures to protect her comrades at arms, even when dealing with fellow Bajorans. And Odo and Quark just offer plenty of that semi-friendly jousting that provided entertainment throughout the run of the show.
These types of TNG-lite episodes showed up a lot during DS9's 1st season, but became much less frequent thereafter. And a good thing too.