Technical Abstract: We assessed the evolutionary consequences of swine husbandry for Trichinella spiralis, a food borne parasite that causes severe muscular disease. We find far less genetic diversity in parasites of domesticated pigs than in related parasites of wildlife hosts. In particular, pigs of European origin harbor extraordinarily uniform parasites despite their especially widespread distribution. The relatively recent domestication and dispersal of European pigs may explain these and similar data for the pork tapeworm, Taenia solium. Taken together, our findings establish that although hominids likely ingested food borne parasites millions of years before the advent of agriculture, the major zoonotic parasites of pigs were disseminated by people only within the last 500 years.