What is bilharzia?

Bilharzia (also known as snail fever and schistosomiasis) is an illness that develops when people come into contact with water contaminated by certain snails carrying the disease-causing parasites, which penetrate the skin and move through the body.

Infection primarily affects the urinary or intestinal system, causing chronic ill health and in some cases death. Poor hygiene and water-based activities (such as swimming and fishing) make school-age children the most vulnerable, with infection responsible for malnutrition, absenteeism, and impaired intellectual development.

Children suffering from persistent and severe bilharzia infections are also likely to have chronic irreversible diseases later in life, such as scarring (fibrosis) of the liver, bladder cancer, or kidney failure.

In women, bilharzia can lead lead to female genital schistosomiasis (FGS) which can cause complications in pregnancy and triple the risk of contracting HIV. 

People affected by bilharzia

220 million people required treatment in 2017 96% of people requiring preventive chemotherapy live in Africa 52 countries require preventive treatment for bilharzia

WHO NTD roadmap targets for bilharzia

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 bilharzia.

Bilharzia target: Control by 2020

  • Control morbidity and achieve treatment coverage of at least 75% of all school-age children by 2020
  • Regional elimination in the Eastern Mediterranean Region, the Caribbean, Indonesia and the Mekong River Basin by 2015
  • Regional elimination in the Americas Region, Western Pacific Region and in selected countries in the African Region by 2020

Mass drug administration status for school-aged children for bilharzia

People receiving preventive chemotherapy for bilharzia

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


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