Soil-transmitted Helminths
sOI-uhl trans-mIt-uhd hEl-minth

Soil-transmitted Helminths (STH) are intestinal worms (“helminth” means parasitic worm) infecting humans that are spread through contaminated soil. STH infection is found mainly in warm and moist climates where sanitation and hygiene are poor. STH are considered neglected tropical diseases (NTDs) because they inflict tremendous disability and suffering yet can be controlled or eliminated.
There are three types of STH that infect a large part of the world’s population: roundworm (Ascaris lumbricoides), whipworm (Trichuris trichiura), and hookworm (Ancylostoma duodenale and Necator americanus).
Quiz
Key Facts
- Soil-transmitted helminths live in the intestine and their eggs are passed in the stool (poop) of infected people.
- Hookworm infections often occur in areas where human feces are used as fertilizer or where defecation onto soil happens.
- Hookworm infection is transmitted primarily by walking barefoot on contaminated soil.
- Ascariasis is the most common human worm infection, with 800 million to 1.2 billion people affected worldwide.
- Soil-transmitted helminths are more common in areas where people lack safe access to adequate sanitation.
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Prevention Tips
- Always wash hands with soap and water after working in the soil and before eating or handling food to help prevent infection from soil-transmitted helminths, especially in areas where sanitation and hygiene may be poor.
- Avoid ingesting soil that may be contaminated with human feces, including where human fecal matter (“night soil”) or wastewater is used to fertilize crops.
- Thoroughly wash and peel or cook fruits and vegetables grown in soil that has been fertilized with human fecal matter (“night soil”) or wastewater.
- The best way to avoid hookworm infection is not to walk barefoot in areas where hookworm is common and where there may be human fecal contamination of the soil. Also, avoid other skin contact with such soil and avoid ingesting it.