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Scale-up of Treatment for Schistosomiasis and Soil Transmitted Helminths

The aim of this research theme is to increase the access and distribution of anti-helminthic drugs to control soil transmitted helminthiasis (STH) and schistosomiasis. To direct mass drug administration and to monitor its impact the prevalence of disease needs to be established. Traditional diagnostic methods are pragmatic but lack the sensitivity and specificity of more recent, molecular based, techniques. It is hoped that by including a TaqMan® assay into the prevalence survey a more accurate prevalence landscape can be achieved.

A novel opportunity to scale up the diagnostics is being investigated by co-opting samples from the Global Polio Laboratory Network and screening these for STH and schistosomiasis.

Global Polio Laboratory Network

The Global Polio Laboratory Network covers 19 African countries and a total of 100,000 faecal samples are collected per year. These samples are screened in well-equipped laboratories in country, staffed by highly skilled technicians. The Network provides a readily available resource that could be tapped into for STH and schistosomiasis control, the suitability of this resource will be investigated. This work will screen 1000 faecal samples from the Ghanaian polio laboratory service with STH and schistosomiasis specific primers and probes. 

Community screening

To establish a baseline of the prevalence of both STH and schistosomiasis a cross sectional survey will be carried out targeting the Greater Accra Region and Volta Region in Ghana. School age children will make up the majority of those sampled, however pre-school aged children and adults, including pregnant women will also be included.

The inclusion of adult women, both pregnant and non-pregnant, is an important issue as approximately 10 million women have schistosomiasis during pregnancy. This results in severe anaemia, low birth weight infants and an increase in mother and childhood mortality.

The effects of the disease are not limited to pregnant women, schistosomiasis can also develop into female genital schistosomiasis, which is estimated to affect between 20 to 150 million women across sub-Saharan Africa. Female genital schistosomiasis has been shown to cause uterine enlargement, menstrual disorders, cervicitis and infertility, it has also been associated with a 3-4 fold increase in the acquisition of HIV during sexual intercourse. Potentially female genital schistosomiasis may be a very important co-factor in the HIV epidemic in sub-Saharan Africa.

The data generated by the community screening will be fed back into the ministry of health and help inform mass drug administration, continuous community surveys will then monitor the success of the intervention.

Traditional diagnostics

To assess the community for the presence of STH and schistosomiasis urine and faecal samples will undergo traditional diagnostics in the field as they provide a pragmatic initial first step towards establishing prevalence estimates. These traditional methods will include Kato-Katz, urine filtration, urine cathodic circulating antigen RDTs and dipsticks testing for heme in the urine.

TaqMan®

In conjunction with the traditional diagnostics a series of multiplex TaqMan® assays will be used to target the following parasitic helminths: Ascaris lumbricoides, Trichuris trichuria, Strongyloides stercoralis, Necator americanus, Ancylostoma duodenale and Schistosoma sp. using this molecular method will confirm the positive samples identified in using Kato-Katz. Using molecular methods will also be a more sensitive approach in detecting S. stercoralis as this particular parasitic worm is note readily identified using the traditional methods described.

qPCR Workshops

Throughout the course of the programme there will be regular molecular workshops as these have proven to be popular and a good way of capacity building at the local level. The workshops also provide a platform to facilitate cross-talk between different groups and allows for closer interaction between in COUNTDOWN partners.