You attempt to afflict a humanoid that you can touch with a disease.  The target must make a Constitution saving throw.  On a failed save, it contracts the disease and is poisoned for the spell duration.  On a successful save, it is not affected.  A creature poisoned by this spell must make another Constitution saving throw at the end of each of its turns.  If it fails a save, the creature has its current and maximum hit points reduced by 2d6.  The reduction lasts until the target finishes a short or long rest.  If it succeeds, the spell ends.  If this spell reduces the target to 0 hit points, it dies and its body is reduced to a pile of rotten remains.  The rotten creature can be restored to life only by means of a 5th-level spell or higher, such as Raise Dead.

At Higher Levels:  When you cast this spell using a spell slot of 4th or higher, the reduction increases by 1d6 hit points for each slot level above 3rd.