Answer
Leech is parasite depend on blood sucking for feeding purpose. when attach to human body then it is difficult to detach them. however pouring salt on them is helpfull in detaching from the body. when salt is poured on their body surface, due to osmosis water come out from their body ,pH of their blood chane and all their metabolic process inside body is unbalanced or functionally abnormal as a result leech detach from the body.
