Soil-transmitted helminths are a group of intestinal worms that include Ascaris lumbricoides (giant roundworm), Trichuris trichiura (whipworm), and Ancylostoma spp. (A. duodenale, A. ceylanicum) and Necator americanus (hookworms). Despite the clear biological differences among the different species, their transmission is characterized by the same sequence of events: (i) infected individuals excrete worm eggs through their stool in soil; (ii) under optimal conditions of moisture and temperature the excreted eggs develop into infectious stages; and (iii) finally, infection occurs through oral uptake (Ascaris, Ancylostoma and Trichuris) or skin penetration (Ancylostoma and Necator) of these infectious stages (embryonated eggs and third stage larvae) that reside in the soil and/or in the environment (referring to their common name).