Even that has its downsides. Many people in the developed world now suffer from autoimmune ailments such as ulcerative colitis and Crohn’s disease that are all but unknown in parts of the world where intestinal parasites are still common. My wife had major life-altering surgery before learning that exposing yourself to certain parasites is a promising new treatment for UC, basically because it can give an overactive immune system something to attack other than the body itself.
On balance we’ve probably helped more people by eliminating those parasites than we’ve harmed though.
