bloodsucking

That draws off the blood of another animal, or a person.

Bedbugs win neither praise for their sophisticated technique, nor very much respect for the fact that they don’t carry diseases, as most bloodsucking human ectoparasites do.

parasitic, leechlike or freeloading

Parasitic, leechlike behavior.

Economic blood-sucking of the Indian peoples, who are forced to pay immense sums of money to sustain rich Indian Civil Servants