I have two other ability, from DotA, who can be called "curse" :
1) Poison touch (can be transform in Frozen touch (Galeoth))
Each second, the target, is slowed more and more until he is stopped. Deal damage/sec, too.
2) Maledict
Each second the target takes some damage. Plus, each 4 second, the target takes damage proportionally as how much HP he lose since the beginning of the curse.
I hope I was understandable.