Assuming for a moment that evolution, or macro-evolution, is not responsible for the diversity of life then explain where these little devils came from.
You probably recognize the tick, flea and mosquito. The parasitic wasp of the Ichneumonidae family may be less familiar. Malaria might be hard to recognize. As for the cymothoa exigua, do not research this creature on a full stomach.
I could have added snakes and spiders with necrotic venom, lampreys, anthrax, chiggers (OMG the chiggers!), tapeworms... the list goes on. For that matter, why would a god make a world for humans and include ANY plants that are toxic or even irritating to humans? "Mysterious ways" or fallacious mythology? Would you call this "un-intelligent design" or "malicious design?" Does anyone want to blame this on scrumping? If we owe this world to a creator, it was either cruel, indifferent or incompetent.