Schistosomiasis Diagnosis Using a CAA Antigen Test
Status:
Recruiting
Trial end date:
2022-05-01
Target enrollment:
Participant gender:
Summary
Schistosomiasis is one of most important human parasitic diseases worldwide. Pregnant women
and their infants are two vulnerable population groups, particularly in sub-Saharan Africa,
where - amongst other infectious agents - they are heavily exposed to infections with S.
haematobium. Adoption of the recommendation and implementation by national disease control
programs was however delayed in most African countries, due to the lack of safety data in
humans and in the unborn babies. First results from randomized controlled trials with PZQ in
pregnant women meanwhile have provided evidence for the safety of PZQ also in newborns.
In Gabon, S. haematobium is the primarily prevalent Schistosoma species infection. As it is
true for most of observational and interventional studies on schistosomiasis, the power of
the study is weakened due to the low sensitivity of reference schistosomiasis diagnosis
applied, and one might correctly assume that a considerable proportion of samples were
misclassified as negative in the control groups. Therefore, diagnostic tests that are highly
sensitive and specific are essential to the detection of Schistosoma infections and are
urgently needed for a test-and-treat strategy to control schistosomiasis in pregnancy as well
as tools to determine efficacy of new interventions tested in clinical trials. Circulating
anodic antigen (CAA) and circulating cathodic antigen (CCA) have levels correlating with the
number of worms and have also been shown to clear within a few days or weeks after successful
treatment. Assays measuring serum levels of these antigens (POC-CCA, UCP-LF CAA) are
therefore deemed to assess drug efficacy.
Based on above mentioned tools, we decided to assess the accuracy of CAA measurement to
determine the Schistosoma infection in two specific conditions: A) as a diagnostic tool for
S. haematobium to prepare for the future implementation of a PZQ test-and-treat strategy and
B) as a diagnostic tool to measure efficacy of praziquantel in schistosomiasis and pregnancy
intervention trials.