A major public health problem

A child being measured against a dose-pole and taking praziquantel, two crucial steps in implementing preventive chemotherapy. ©Lester Chitsulo/WHO

Schistosomiasis is a disease of poverty that leads to chronic ill-health. Infection is acquired when people come into contact with fresh water infested with the larval forms (cercariae) of parasitic blood flukes, known as schistosomes. The microscopic adult worms live in the veins draining the urinary tract and intestines. Most of the eggs they lay are trapped in the tissues and the body’s reaction to them can cause massive damage.

Schistosomiasis affects almost 240 million people worldwide, and more than 700 million people live in endemic areas. The infection is prevalent in tropical and sub-tropical areas, in poor communities without potable water and adequate sanitation. Urogenital schistosomiasis is caused by Schistosoma haematobium and intestinal schistosomiasis by any of the organisms S. guineensis, S. intercalatum, S. mansoni, S. japonicum, and S. mekongi.

Several million people all over the world suffer from severe morbidity as a consequence of schistosomiasis.

The WHO strategy on use of anthelminthic drugs now makes it possible to control schistosomiasis in poor and marginalized communities, in conjunction with interventions against lymphatic filariasis, onchocerciasis and soil transmitted helminthiasis. In highly endemic areas, severe morbidity due to schistosomiasis can be prevented by regular treatment of at risk groups targeted based on community diagnosis based on sentinel groups. Praziquantel has been safely co-administered with albendazole and ivermectin, in areas where these drugs have been used separately for preventive chemotherapy.

WHO coordinated strategy

Preventive chemotherapy in human helminthiasis

This manual and its dose-poles provide health professionals and programmes managers with the latest recommendations. Ref: ISBN 92 4 154710 3

If you have any queries, please do not hesitate to contact us at

Latest news

30 January 2015 | Geneva

27 March 2014 | Geneva
New factfile on schistosomiasis

14 February 2013 | Geneva
"Bambo has bilharzia: What children should know about bilharzia".

PCT Databank (SCH)