Why did God create the Loa Loa worm?

Why did God create the Loa Loa worm, or African eye worm? This is a parasite that enters the body, burrows up to the eye then exits via a person's eyeball, causing a great suffering. What kind of being would create such a thing, to plague countless generations of perfectly innocent children? Why did God do this? Was it because Adam and Eve upset God in the Garden of Eden? Christians believe that Adam and Eve were created perfect. When they disobeyed God, he got angry and made them imperfect, to feel pain and to have disease. When he got angry he must have changed their DNA to make them susceptible to disease like arthritis and cancer and virus’s like swine flu. If this is true why did he introduce identical DNA errors into countless animal species, making them susceptible to the same diseases as humans? Did all these animals upset God in the Garden of Eden? Is this just an example of God’s plan, or God moving in a mysterious way? Why does God continue to let this parasite exist?