WHO | Schistosomiasis: large-scale treatment decreases prevalence by 60% among school-aged children

07 Dec 2021

Schistosomiasis prevalence has reduced by almost 60% across sub-Saharan Africa over the past 20 years, thanks to preventative treatment using praziquantel, according to a recent The Lancet publication from World Health Organization, Swiss Tropical and Public Health Institute, University of Basel, European Research Council and colleagues.

Progress to Schistosomiasis Elimination as a Public Health Problem

Mass treatment of at-risk groups with priority focus on school-aged children has been the mainstay of the global schistosomiasis programme of the World Health Organization (WHO). Praziquantel, the treatment of choice for schistosomiasis, is on the WHO Essential Medicines List, and has been donated by Merck since 2007. Since then the number of people treated for schistosomiasis has greatly increased from only 7million individuals in 2006 to 76·2 million school-aged children (61.2% SAC treatment coverage) and 19·1 million adults (18.2% adult treatment coverage) in 2018. 

The study shows the scale of the impact large-scale preventive chemotherapy (PC) can have on schistosomiasis prevalence across the region with the highest schistosomiasis burden.

This massive decrease in prevalence has been achieved through mass medicine administration predominantly focused on school-aged children and school-based delivery platforms. These findings suggest that by ensuring praziquantel is available to all at-risk groups, developing a paediatric formulation to include preschool-aged children in treatment campaigns, and implementing integrated strategies in collaboration with water, sanitation and hygiene (WASH), snail control, education and awareness-raising will enable us to achieve the WHO global target of schistosomiasis elimination as a public health problem.

About the study

The spatio-temporal modelling study was led by the Swiss Tropical and Public Health Institute (a WHO collaborating centre) in collaboration with WHO, the University of Basel and partners. It was funded by the European Research Council and WHO.

Effect of preventive chemotherapy with praziquantel on schistosomiasis among school-aged children in sub-Saharan Africa: a spatiotemporal modelling study was published in the Lancet Infectious Diseases. It analyses cross-sectional survey data of school-aged children (aged 5–14 years) in 44 countries across sub-Saharan Africa.  Models were used with data on both Schistosoma haematobium and S. mansoni at three different time periods (2000-2010, 2011-2014 and 2015-2019).

The study could potentially assist policy makers to plan their future schistosomiasis control and elimination strategies.

Read the full article on the WHO website