Schistosomiasis and STHs are caused by parasitic worms. More than one billion people are affected globally. These diseases cause chronic health and development problems including, abdominal pain, anaemia, malnutrition and stunted growth in children as well as rarer and more serious complications.

Ascaris lumbricoides (roundworms), DRC. Credit: Johnny Vlaminck, Starworms
Ascaris lumbricoides (roundworms), DRC. Credit: Johnny Vlaminck, Starworms

The latest estimate from the Lancet Global Burden of Disease Study (2016) is that the approximately 5.2 million disability-adjusted life-years (DALYs) associated with schistosomiasis and the STHs ascariasis, trichuriasis, and hookworm account for nearly 30% of all DALYs associated with the neglected tropical diseases.

The strategy recommended by the World Health Organization (WHO) to treat and control these diseases is regular mass distribution of praziquantel (for schistosomiasis) and albendazole or mebendazole (for ascariasis, trichuriasis, and hookworm) to affected communities. Approximately 700 million people at risk for schistosomiasis or STHs were treated in 2017 as part of the ongoing and unprecedented scale-up of drug distribution towards the WHO’s 2020 control and elimination targets.

The ongoing effectiveness of this vast control effort could be threatened by changes in parasite ecology, natural immunity, and the selection of parasites with resistance or reduced susceptibility to the current medicines. There is a need to better understand optimal dosing in different population subgroups, the influence of co-infections, and the medicine side effect profiles in different demographic groups. Trials of new treatments, repurposed medicines, or new drug combinations need to be undertaken and analysed in the context of current standard treatments.

General information: