Schistosomiasis

28 February 2018

Schistosomiasis is an acute and chronic, parasitic disease caused by blood flukes (trematode worms) of the genus Schistosoma. At least 206 million people required treatment in 2016. Treatment, which should be repeated over a number of years, will reduce and prevent morbidity. The WHO strategy for schistosomiasis control focuses on reducing disease morbidity through periodic, targeted treatment with praziquantel. This involves regular treatment of all who are at-risk.

WHO/C. Banluta

More people need treatment for schistosomiasis

At least 206 million people are estimated to have required treatment for schistosomiasis in 2016. While the actual reported number of people treated in 2016 was 89.2 million.

WHO/S. Lim

Larval forms of schistosomiasis are released by snails

People become infected when larval forms of the parasite – released by freshwater snails – penetrate the skin during contact with infested water.

WHO/L. Chitsulo

Schistosomiasis is prevalent in tropical and subtropical areas

Schistosomiasis is especially prevalent in poor communities with unsafe drinking-water sources and inadequate sanitation. It is estimated that at least 90% of those requiring treatment for schistosomiasis live in Africa.

Increased population movement is introducing the disease to new areas

Increased migration to urban areas and population movements are introducing schistosomiasis to new areas. Increasing population size and the corresponding needs for power and water often result in development schemes and environmental modification, such as construction of dams, that facilitate transmission.

Merck

The economic and health effects of schistosomiasis are considerable

In children, schistosomiasis causes anaemia, stunted growth and reduced ability to learn, although its effects are usually reversible with treatment. Chronic schistosomiasis can affect people’s ability to work and, in some cases, result in death. Female genital schistosomiasis (FGS) symptoms of vaginal discharge, bleeding, and pain during sexual intercourse can also lead to infertility.

WHO/L. Chitsulo

Urine and stool samples can detect schistosomiasis

Urogenital schistosomiasis can be easily detected through the presence of blood in urine (haematuria). Intestinal forms of schistosomiasis can cause abdominal pain, diarrhoea and blood in the stool, are diagnosed through examination of stool specimens.

Merck

Praziquantel can be used to treat schistosomiasis

Control of schistosomiasis is based on large-scale treatment with praziquantel of at-risk populations. WHO recommends treatment with praziquantel against all forms of schistosomiasis. The medicine is effective, safe and is distributed free during large-scale treatment campaigns.

WHO/L. Chitsulo

WHO has developed treatment methods and recommendations

WHO has also developed methods and recommendations to reach communities and simplify large-scale preventive treatment with praziquantel. Other methods of schistosomiasis control include improved sanitation, clean water supply, health education and snail control.

Merck

WHO advocates for increased access to praziquantel and resources for implementation

WHO has catalysed collaboration between ministries of health, development agencies, the pharmaceutical sector, non-profit organizations and communities to provide resources and medicines for schistosomiasis control.