Figure 3.

Introduction of soil-transmitted helminths into the Americas.

It is unlikely that soil-transmitted helminths (A. duodenale, N. americanus, T. trichiura, A. lumbricoides, and S. stercoralis) have been introduced into the New World by humans migrating through Beringia (red arrow) because the harsh climate conditions of this route would have been detrimental for the development of their free-living life cycle stages [5]. Instead, soil-transmitted helminths could have been introduced into the New World via costal migration (blue arrows) and/or trans-pacific migration (green arrow) in pre-historic times [5,61–63].