Neglected tropical diseases

New agreement expands access to schistosomiasis treatment for millions

Geneva | 12 February 2013

The World Health Organization (WHO) today signed a Memorandum of Understanding (MoU) with Merck KGaA enabling the pharmaceutical company to increase its donation of praziquantel tablets from 20 million to 250 million annually.

This 10-fold increase from the original agreement signed in 2007 will allow WHO to work with countries where schistosomiasis (also known as bilharzia) is endemic and with implementation partners to coordinate scaling up of interventions for treatment of as many as 100 million school-age children per year.

This increase in donated praziquantel fills an important gap in supply to countries where it is needed and allows us to reach the targets set by previous World Health Assembly resolutions and as outlined in WHO’s 2012–2020 roadmap”, said Dr Lorenzo Savioli, Director of WHO’s Department of Control of Neglected Tropical Diseases. “What we now need is to strengthen country capacity to scale-up interventions.

More than 230 million people require treatment for this preventable disease annually. WHO estimates that at least 90% of those requiring treatment live in Africa. Transmission of schistosomiasis has been documented in at least 78 tropical and subtropical countries and regions, especially in communities of poor people with little or no access to safe drinking-water sources and adequate sanitation.

Today’s agreement fulfills the dream of all those who fought to provide universal access to bilharzia treatment. Here, I want to pay tribute particularly to late Dr Andrew (Rikk) Davis, former Director of Parasitic Diseases at WHO, who played a pivotal role in the development of and clinical trials for praziquantel, which radically changed the treatment and control of schistosomiasis” added Dr Savioli.

Hygiene and recreational habits make children especially vulnerable to infection. The disease also affects populations engaged in agricultural activities and fishing, as well as women during domestic work in infested water sources such as washing clothes.

There are two major forms of the disease – intestinal and urogenital. The classic sign of urogenital schistosomiasis is haematuria (blood in urine).

Infection causes a wide range of symptoms, including abdominal pain, diarrhoea and blood in the stool. Liver enlargement is common in advanced cases.

In children, schistosomiasis can cause anaemia, stunted growth and reduced ability to learn, although the effects are usually reversible with treatment. Chronic schistosomiasis may affect people’s ability to work and is fatal in some cases. Repeated treatment in childhood prevents the development of chronic morbidity that is normally noted in later life (in adults).


WHO's strategy for schistosomiasis control targets mainly school age children who are most vulnerable for infection. It aims to reduce morbidity through the regular treatment with praziquantel, the only available medicine, through school-based and/or community-based deworming programmes.

Praziquantel is safe and efficacious, with transient side-effects. It has been successfully used over the past 30 years. Although re-infection may occur, providing at least three treatments during childhood greatly reduces the risk of serious manifestations of schistosomiasis in adulthood.

Praziquantel is also safe in pregnancy, and it is recommended that women, and adolescent girls of child-bearing age, should not be excluded from public health interventions.