Global Overview of Schistosomiasis Research and Control

Schistosomiasis is transmitted through infective larvae that penetrate the skin

Schistosomiasis is transmitted through infective larvae that penetrate the skin of humans during water contact (Photo: Thomas Schuppisser)

An estimated 250 million people suffer from schistosomiasis worldwide. While considerable progress has been made to control schistosomiasis, challenges remain as there is no vaccine available and the risk for drug resistance is increasing. Providing recommendations toward control and eventual elimination of schistosomiasis, a comprehensive review was published today in the peer-reviewed journal Nature Reviews Disease Primers.

Schistosomiasis is a neglected tropical disease and caused by blood flukes (parasitic flatworms) of the genus Schistosoma . Globally, almost 800 million people are at risk of schistosomiasis. Of the 250 million infected people, 200 million live in Africa.

Infection occurs when infective larvae released from freshwater snails penetrate the skin of humans during water contact. The mature female worms lay eggs which are partially trapped in tissues and organs, causing inflammation that gives rise to a complex chronic intestinal or urogenital disease. When left untreated, schistosomiasis can lead to anaemia, stunted growth, severe damage of organs, and - at worst - death.

Challenges in prevention and treatment

Today, the peer-reviewed journal Nature Reviews Disease Primers published the first "Primer" on schistosomiasis, providing an authoritative global overview of the epidemiology, control and elimination of the disease and challenges facing the scientific community and disease control managers as they strive towards elimination of this debilitating condition.

Challenges include the lack of preventive tools and potential resistance to the current medication. "We still have no vaccine available to prevent schistosomiasis," said Don McManus, Professor at the QIMR Berghofer Medical Research Institute in Brisbane, Australia and lead author of the publication. "In addition, while the current treatment of choice - praziquantel - is safe and efficacious, it does not prevent reinfection and there is a potential threat of resistance development as drug pressure mounts."

Need for multifaceted approach

"To control, let alone eliminate schistosomiasis, we need a multifaceted approach, including new treatment options, accurate diagnostics, snail control interventions, improved sanitation and hygiene, education and communication and well-tailored surveillance-response systems." said Jürg Utzinger, Director of Swiss TPH and co-author of the publication. The WHO target of potential global elimination of schistosomiasis as a public health problem is set for 2025.

Research and development for new treatments

To discover and develop novel drugs for treating schistosomiasis, Swiss TPH works with different academic institutions and the private sector. Under the umbrella of the Pediatric Praziquantel Consortium, Swiss TPH joined forces to develop a more suitable formulation of praziquantel for children under the age of 6 years. Members of the consortium include Merck, Astrellas, Lygature, Farmanguinhos, the Schistosomiasis Control Initiative and the Université Félix Houphouët-Boigny.

About the publication

Nature Reviews Disease Primers is a Nature Research journal launched in 2015. Each "Primer" provides a global overview on various health fields and outlines key open research questions. This is the first Primer on schistosomiasis.

McManus D.P., Dunne D, Sacko M., Utzinger J., Vennervald B., Zhou X. (2018) Schistosomiasis. Nature Reviews Disease Primers. doi.org/10.1038/s415­72-018-0013-8