What is soil-transmitted helminths?

Soil-transmitted helminths (STH) are a group of intestinal parasites that thrive in places where the soil is warm and humid, and sanitation is poor. The most common STH-causing parasites are roundworm, whipworm and hookworm.

People become infected after they come into contact with soil contaminated with the parasites’ eggs. Soil-transmitted helminths reduces the body’s ability to absorb nutrients and vitamins. This exacerbates malnutrition and leads to anaemia, increased susceptibility to other infectious diseases, stunted growth, and impaired intellectual development. Symptoms of STH become more evident as the worm load in a person increases.

STH is a poverty-related disease, linked to broader community development challenges, which severely limits the ability of those infected to live full and productive lives.

People affected by soil-transmitted helminths

1.5 billion people are infected worldwide 269 million school-age children are at risk of contracting STH 75% of children requiring preventive chemotherapy live in South-East Asia and Africa

WHO NTD roadmap targets for STH

The World Health Organization’s roadmap on NTDs set out a comprehensive plan for the control, elimination and eradication of various neglected tropical diseases by 2020, including soil-transmitted helminths.

Soil-transmitted helminths target: Control by 2020
75% of pre-school and school-age children in need are treated by 2020


Progress and scorecard from the 5th progress report

Since 2012, we have monitored progress annually for each disease. This information is from the 5th progress report of the London Declaration published in 2017.

Coverage and impact
Programme support
Drug requests filled
Overall progress

Mass drug administration status for school-age children for STH

People receiving preventive chemotherapy for STH

Since the London Declaration was signed in 2012 and partners committed to defeating neglected tropical diseases, the number of people receiving preventive chemotherapy for soil-transmitted helminths has increased considerably.


  • Data is provided by the World Health Organization
  • Photo: © GSK / Marcus Perkins