Schistosomiasis: number of people treated worldwide in 2013

Overview

 Schistosomiasis is caused by blood flukes (trematodes) of the genus Schistosoma. Six species infect humans: S. guineensis, S. haematobium, S. intercalatum, S. japonicum, S. mansoni and S. mekongi, of which S. haematobium and S. mansoni are the predominant causes of disease. Schistosomiasis occurs in intestinal and urogenital forms. Transmission of infection begins when human excreta containing parasite eggs reach fresh water bodies and hatched larvae infect susceptible snail hosts. Parasites undergo asexual multiplication in snails and another larval stage, infective to humans, is released into water. People are infected during domestic, occupational and recreational water contact.

The distribution of schistosomiasis is focal, as transmission depends on specific snail hosts and particular human activities, with endemicity continuously changing as a result of environmental alteration, water development schemes, migration, control interventions and snail host distribution.

This report presents data on the number of people treated for schistosomiasis globally, and by WHO region and country, in 2013. The estimated total number of people requiring treatment for schistosomiasis for 2013 was 261 008 019, of whom 121 170 936 (46.4%) were school-age children (5–14 years of age). In 2013, 92% of the people estimated to require treatment for schistosomiasis lived in the WHO African Region. Reporting on treatments shows progress in implementation of control to prevent and/or reduce morbidity. Other parameters are required to assess comprehensive schistosomiasis control programmes that include access to water, sanitation, hygiene education, and snail control.