> modern city planning One theory has to do with sanitation and how well we've done at eliminating parasites. Some people have reported successfully curing all

> modern city planning One theory has to do with sanitation and how well we've done at eliminating parasites. Some people have reported successfully curing allergies by giving themselves a hookworm infection. > The fact that some local African languages contain no words to describe allergic symptoms could support this hypothesis, indicating that allergic diseases have never been a problem among these populations https://pmc.ncbi.nlm.nih.gov/articles/PMC6585781/ https://pmc.ncbi.nlm.nih.gov/articles/PMC6585781/