Five-Year Impact of Different Multi-Year Mass Drug Administration Strategies on Childhood Schistosoma mansoni–Associated Morbidity: A Combined Analysis from the Schistosomiasis Consortium for Operational Research and Evaluation Cohort Studies in the Lake Victoria Regions of Kenya and Tanzania

Ye Shen,Pauline N M Mwinzi,Ryan E Wiegand,Sue Binder,William Evan Secor,Feng Zhang,Safari Kinung’Hi,Daniel G Colley,Susan P Montgomery,Carl H Campbell,Pascal Magnussen,Annette Olsen,Christopher C Whalen,Charles H King,Nupur Kittur

doi:10.4269/ajtmh.19-0273

Abstract

.The WHO recommends mass treatment with praziquantel as the primary approach for Schistosoma mansoni–related morbidity control in endemic populations. The Schistosomiasis Consortium for Operational Research and Evaluation implemented multi-country, cluster-randomized trials to compare effectiveness of community-wide and school-based treatment (SBT) regimens on prevalence and intensity of schistosomiasis. To assess the impact of two different treatment schedules on S. mansoni–associated morbidity in children, cohort studies were nested within the randomized trials conducted in villages in Kenya and Tanzania having baseline prevalence ≥ 25%. Children aged 7–8 years were enrolled at baseline and followed to ages 11–12 years. Infection intensity and odds of infection were reduced both in villages receiving four years of annual community-wide treatment (CWT) and those who received biennial SBT over 4 years. These regimens were also associated with reduced odds of undernutrition and reduced odds of portal vein dilation at follow-up. However, neither hemoglobin levels nor the prevalence of the rare abnormal pattern C liver scores on ultrasound improved. For the combined cohorts, growth stunting worsened in the areas receiving biennial SBT, and maximal oxygen uptake as estimated by fitness testing scores declined under both regimens. After adjusting for imbalance in starting prevalence between study arms, children in villages receiving annual CWT had significantly greater decreases in infection prevalence and intensity than those villages receiving biennial SBT. Although health-related quality-of-life scores improved in both study arms, children in the CWT villages gained significantly more. We conclude that programs using annual CWT are likely to achieve better overall S. mansoni morbidity control than those implementing only biennial SBT.

Highlights

Schistosomiasis remains a major public health problem in much of Africa
The results reported in this article are a secondary analysis of data combined from parallel cohort studies that took place in the Nyanza region (Siaya, Kisumu, and Homa Bay counties) of Kenya[13] and the Mwanza region (Misungwi and Sengerema districts) of Tanzania,[9] both of which have high prevalence of S. mansoni
Mean intensities for the entire cohort at baseline were 148 epg for children in the annual community-wide treatment (CWT) arm, which is significantly higher than the 110 epg for those in the biennial school-based treatment (SBT) arm (Figure 3)

Summary

Introduction

Schistosomiasis remains a major public health problem in much of Africa. The clinical consequences of Schistosoma mansoni infections result from tissue damage and blood loss caused by schistosome eggs trapped in host tissues.[1]. Current WHO guidelines call for mass treatment with praziquantel in endemic communities to achieve morbidity control.[4,5,6] questions remain about optimal programmatic implementation of mass drug administration (MDA)

Methods

Results

Conclusion