Fast and reliable easy-to-use-diagnostics for eliminating Bilharzia in young children and mothers

About

Schistosoma antigen detection tests have a large potential for schistosomiasis control programmes due to their much higher sensitivity compared to parasitological methods and preferred use of urine over stool samples in the diagnosis of schistosomiasis. Highly accurate diagnostics are of paramount importance especially in low transmission areas that have experienced years of advanced control programmes. Pregnant women and young children could especially benefit from affordable and easy-to-use antigen tests as inclusion of these particularly vulnerable groups in mass drug administration (MDA) campaigns with praziquantel (PZQ ) will always require higher justification hurdles. This is especially the case in regions of low to middle endemicity where a higher proportion of individuals are not-infected and thus unnecessarily exposed to PZQ.

Since 2008, a point-of-care diagnostic test (POC-CCA) detecting Schistosoma derived circulating cathodic antigen (CCA) in urine is commercially available. This diagnostic test is particularly useful for diagnosing intestinal schistosomiasis with weaker test performance (sensitivity) for urinary schistosomiasis. In contrast, the laboratory-based, up-converting phosphor based lateral flow (UCP-LF) test detecting circulating anodic antigen (CAA) of all Schistosoma species in urine is exceptionally sensitive and specific. This test quantifies CAA levels that reflect active, ongoing infections of less than a single Schistosoma worm.

Goal

The overall objective of the study is to thoroughly evaluate the accuracy of CAA and CCA tests to diagnose Schistosoma infections in women and young children.

 

Clinical trials

The freeBILy study includes two clinical trials in two different settings:

‘Clinical trial to assess Test-Based-Schistosomiasis-Treatment (TBST) in pregnant women and young children’

This clinical trial will take place in Madagascar and will focus on the integration of POC-CCA Test-Based-Schistosomiasis-Treatment (TBST) into routine mother child primary health care programmes in order to demonstrate its usefulness for controlling intestinal schistosomiasis in pregnant women and young children and assess the diagnostic performance of the POC-CCA test.

‘Diagnostic studies in Gabon’

In Gabon, the accuracy of the UCP-LF-CAA test in a cross-sectional, multicentre, prospective clinical study in pregnant women for detection of S. haematobium infections will be thoroughly evaluated. An additional objective is to validate CAA as an endpoint measure to determine PZQ efficacy in an intervention trial in pregnant women.

Developmental component

Both CAA and CCA have been characterised and the diagnostic tests developed by Leiden University Medical Center (LUMC). To combine the sensitivity and specificity of the POC-CCA test for S. mansoni infections with the ultrasensitive and specific UCP-LF-CAA test for all Schistosoma species, we are developing a CAA/CCA duplex test at the LUMC.

 

Cost-effectiveness evaluation

In addition to the clinical trial in Madagascar, we also want to accurately assess cost-effectiveness of TBST using POC-CCA as primary health care diagnostic with PZQ treatment on child development in comparison with the traditional primary health care approach.

 

Capacity development and networking activities

The freeBILy project provides an on-the-job scientific training platform for both African and European centres in applied epidemiology and mother-child public health. The overall aim of this WP is to provide the training measures to build capacity for the implementation of the freeBILy study procedures and laboratory diagnostic methods. This will be done in a standardized way ensuring quality assurance. Activities include infrastructural upgrading of sites, training in schistosomiasis diagnostics, training of field teams and increasing the number of qualified parasitologists in Central and East Africa. Furthermore, freeBILy is a network between project partners for training and capacity building of health care workers such as clinical teams at antenatal healthcare centres, laboratory personnel and students in medicine and biomedical sciences. Training may also include field workers of the ministries of health and their respective programmes in Gabon as well as Madagascar.