Need for a paradigm shift in soil-transmitted helminthiasis control: Targeting the right people, in the right place, and with the right drug(s)

Abstract

“The worst form of inequality is to try to make unequal things equal”—AristotleSoil-transmitted helminthiasis (STH) is caused by intestinal parasites that require an obligatedevelopment period in the soil [1,2], predominantly roundworm (Ascaris lumbricoides),whipworm (Trichuris trichiura), and hookworms (Ancylostoma duodenale and Necator americanus),with the recent addition of threadworm (Strongyloides stercoralis). Historically, theseparasites have been among the most common infections in humans, disproportionately affectingthe world’s most disadvantaged and marginalized people.The current approach to STH control and elimination as a public health problem is population-based, eschews adequate monitoring, assumes unlimited donated drugs which are notoptimal against all STH species, and accepts massive programmatic inefficiencies. Hence, anew paradigm is needed. The burden of infection and morbidity due to these parasitic wormsis rapidly declining, likely due to social and economic development and improvements inhygiene and living conditions, as well as the widespread distribution of donated or procuredanthelmintic drugs. Despite this progress, there have been few changes in the structure of theglobal control program. The World Health Organization (WHO), which coordinates drugdonations, reports that between 2010 and 2020, over 9 billion tablets were donated and distributedthrough STH-specific school-based programming, or to entire communities as part of the lymphatic filariasis (LF) elimination program [3]. In addition to the distributions reported byWHO, numerous other organizations, including UNICEF, have procured and distributed billionsmore deworming tablets. Collectively, there has been over a decade of extensive and continuousdistribution of anthelmintic drugs reaching most at-risk populations (but crucially,not all).