Answer:
Microparasite expert at sucking the blood of mammals and birds
While I did live, I food did give, which many one did daily eat. Now being dead, you see they tread me under feet about the street.
A mysterious, fantastic creature, It has one defining feature, And for humans at their worst, In their eyes it's just a horse
I am a rodent that people sometimes keep as pets. I love cheese and have a long tail. What am I?
I have a pouch like a kangaroo but I live in trees and eat eucalyptus leaves. What am I?
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?