Reaching transmission elimination of the soil-transmitted helminths; measuring the multiple heterogeneities in transmission and control
File(s)
Author(s)
Maddren, Rosemary
Type
Thesis
Abstract
Soil-transmitted helminths (STH) currently infect just under a quarter of the world’s population, primarily in tropical climates where access to safe water, sanitation, and hygiene (WaSH) infrastructure is poor, creating optimal conditions for helminth transmission. Guidance for the control of these parasites by the World Health Organisation (WHO) centres upon integrated control: the combination of anthelmintic treatment and improved access to WaSH infrastructure, with community sensitisation to both. National control programs predominantly target school-aged children (SAC), expanding treatment to high-risk groups such as preSAC and women of reproductive age (WRA) in highly endemic areas. Treatment is administered at a prevalence-dependent frequency (biennial, annual, biannual) through mass drug administration (MDA) campaigns, regardless of individual infection status. Such control is targeted with first achieving morbidity control, and subsequently reaching elimination as a public health problem (EPHP), defined by the WHO as <2% moderate and heavy intensity infections (MHII). Despite the immediate efficacy of treatment, STH re-infection is common due to untreated members of the community acting as infection reservoirs, particularly in areas with poor WaSH access.
The Geshiyaro project, located in south Ethiopia, aims to define the optimal combination of MDA and WaSH access to eliminate STH transmission in a low prevalence setting. Using a longitudinal dataset following individuals over six years, this thesis analyses changes in STH prevalence and intensity by the different interventions, using age-sex stratifications across individual, village, and district aggregation levels. This thesis will critically appraise the interventions implemented and fine-scale monitoring methods used to evaluate them, in the context of STH transmission elimination, discussing whether the improvements made to Ethiopia’s Federal Ministry of Health’s (FMoH) NTD control program by the Geshiyaro project justify recommendations for future national control programs.
The Geshiyaro project, located in south Ethiopia, aims to define the optimal combination of MDA and WaSH access to eliminate STH transmission in a low prevalence setting. Using a longitudinal dataset following individuals over six years, this thesis analyses changes in STH prevalence and intensity by the different interventions, using age-sex stratifications across individual, village, and district aggregation levels. This thesis will critically appraise the interventions implemented and fine-scale monitoring methods used to evaluate them, in the context of STH transmission elimination, discussing whether the improvements made to Ethiopia’s Federal Ministry of Health’s (FMoH) NTD control program by the Geshiyaro project justify recommendations for future national control programs.
Version
Open Access
Date Issued
2024-07-17
Date Awarded
01/12/2024
License URL
Advisor
Anderson, Roy
Phillips, Anna
Sponsor
Children's Investment Fund Foundation (Organisation)
Grant Number
P74693
Publisher Department
School of Public Health
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)