I wonder how repulsive it actually was to people 1000 or 5000 or 10000 years ago though. In the wild – especially in the tropics – intestinal parasites are incredibly common in mammals, presumably including our ancestors. The invention of cooking must have reduced the parasitic load among hominins, however, as well as the discovery of soap. Various cultural taboos on eating or handling specific types of animals almost certainly originate from the desire to avoid parasites as well. Also, base parasitic load is reduced for people living in cooler climates, so worm infections may have become more yucky to Europeans not as accustomed to them.