Evaluation of integrated interventions layered on mass drug administration for urogenital schistosomiasis elimination: a cluster-randomised trial

Abstract

Background Elimination of schistosomiasis as a public health problem and interruption of transmission in selected areas are targets set by WHO for 2025. Our aim was to assess biannual mass drug administration (MDA) applied alone or with complementary snail control or behaviour change interventions for the reduction of Schistosoma haematobium prevalence and infection intensity in children from Zanzibar and to compare the effect between the clusters. Methods In a 5-year repeated cross-sectional cluster-randomised trial, 90 shehias (small administrative regions; clusters) in Zanzibar eligible owing to available natural open freshwater bodies and public primary schools were randomly allocated (ratio 1:1:1) to receive one of three interventions: biannual MDA with praziquantel alone (arm 1) or in combination with snail control (arm 2), or behaviour change activities (arm 3). Neither participants nor field or laboratory personnel were blinded to the intervention arms. From 2012 to 2017, annually, a single urine sample was collected from approximately 100 children aged 9-12 years in the main public primary school of each shehia. The primary outcome was S haematobium infection prevalence and intensity in 9-12-year-old children after 5 years of follow-up. This study is completed and was registered with the ISRCTN, number 48837681.

Insights from quantitative and mathematical modelling on the proposed WHO 2030 goal for schistosomiasis

“…To alleviate the need for ongoing treatment and to prevent resurgence, EOT is required after reaching EPHP 2,5,7 . The transition of treatment programmes from EPHP to EOT will require reassessment of the treatment strategy.…”

“…It is an intestinal or urogenital disease caused predominantly by Schistosoma mansoni or S. haematobium. Individuals become infected when cercariae, released by freshwater snails, penetrate the skin during contact with contaminated water 2 . The disease can result in anaemia, chronic pain, diarrhoea, and malnutrition, causing poor school performance and lower fitness 3 .…”

Economic evaluations of human schistosomiasis interventions: a systematic review and identification of associated research needs

“…Modelling studies have indicated that breaking transmission may theoretically be possible with mass preventive chemotherapy alone at high coverage and compliance 98,140 . Field studies and trials are currently underway to confirm if this is feasible in practice 141,142 . Moving towards elimination will likely require more intensive strategies, including treatment in low prevalence settings 14 .…”

Participatory integrated control strategies and elimination of schistosomiasis in sub-Saharan Africa

“…In this issue of Lancet Global Health, Knopp and colleagues' cluster randomised trial provides programmatic insight on how to implement integrated interventions with the goal of elimination of Schistosoma haematobium infection in an African setting with low prevalence (ranging from 4•2%-7•8%). 9 The study, done in Zanzibar, assessed the efficacy of three intervention strategies: biannual MDA with PZQ alone, biannual MDA in combination with snail control, or biannual MDA with PZQ and activities to Several interpretations and conclusions can be drawn from these results. Based on the results, a significant decline in the prevalence of S haematobium can be expected with biannual MDA with PZQ for 5 years without integrating other complementary measures in an area with a relatively low baseline prevalence of S haematobium.…”