Schistosomiasis is a disease that people risk contracting when they use infected water for daily needs.
An estimated 779 million people are at risk of catching the disease globally. It is caused by parasitic worms found in rivers and dams, and is also known as 'snail fever'.
It is also known as bilharzia and can be controlled by an annual dose of medicine that costs about $0.18.
The Lifelines team went to Senegal to see how the disease is affecting some of the population there.
Lifelines: The Quest for Global Health will air on Al Jazeera in 2014.
Source: Al Jazeera