Soil-transmitted helminths are a research focus of the Coalition for Operational Research on Neglected Tropical Diseases (COR-NTD). According to the U.S. Centers for Disease Control and Prevention (CDC):

Soil-transmitted helminths refer to the intestinal worms infecting humans that are transmitted through contaminated soil (“helminth” means parasitic worm): Ascaris lumbricoides (sometimes called just “Ascaris“), whipworm (Trichuris trichiura), and hookworm (Anclostoma duodenale and Necator americanus). A large part of the world’s population is infected with one or more of these soil-transmitted helminths:

• approximately 807-1,121 million with Ascaris
• approximately 604-795 million with whipworm
• approximately 576-740 million with hookworm

Soil-transmitted helminth infection is found mainly in areas with warm and moist climates where sanitation and hygiene are poor, including in temperate zones during warmer months. These STHs are considered Neglected Tropical Diseases (NTDs) because they inflict tremendous disability and suffering yet can be controlled or eliminated.

 Source: Global Health, Division of Parasitic Diseases and Malaria, CDC