Dreams of parasites represent that you are letting little things eat at you. This dream also may be showing you that something or someone (maybe you) in your waking state is draining your energy, eating away at your -esteem, and draining your energy.
See Also: Vampire.
[1]To see a parasite in your dream suggests that you are feeling physically drained.
It is also an indication that you are taking without giving back. You are becoming too dependent on others.
[2]Something or someone that eats away at you and drains energy; can be own negative thinking and fear, or relationship with another person who is sapping energy.
[3]1. An abusive, draining relationship or situation.
2. Dependence to the point of taking advantage.
[4]Insignificant one who lives off others; a moocher
[5]