Abstract
Fasciola hepatica is a worldwide emerging and re-emerging parasite heavily affecting several regions in South America. Some lymnaeid snail species of American origin are among the major hosts of F. hepatica worldwide. Recent paleoparasitological findings detected its DNA in a 2300-year-old sample in Patagonia, countering the common hypothesis of the recent arrival of F. hepatica in the Americas during European colonization. Thus, the theory of an initial introduction in the 1500s can no longer be sustained. This article discusses how it was possible for F. hepatica to reach and spread in the Americas in relation to the availability and compatibility of hosts through natural and incidental introductions. Our study will serve to better understand the ongoing Neotropical scenario of fasciolosis.