Performance of the pooled testing strategy for detecting and estimating the prevalence and intensity of Schistosoma haematobium infection at a population level - PROJECT SUMMARY
Schistosoma haematobium affects more than 112 million people in the world, mainly in sub-Saharan Africa and
the Middle East, causing urogenital schistosomiasis and the majority of bladder cancer cases in these
regions.1-4 There is a lack of cost-effective diagnostic strategies for detecting cases, estimation of
infection prevalence, and evaluation of praziquantel (PZQ) efficacy and mass drug administration (MDA)
programs' effectiveness for controlling this parasitic infection. An innovative procedure called group
testing, also known as pooled testing, has been used to save resources and time by reducing the number
of tests for the diagnosis of different infectious diseases.5-8 The long-term goal is to develop a
standardized, reproducible protocol and to guide interpretation of results for pooling urine samples to
accurately diagnose S. haematobium infection at low cost and in short turnaround time. The overall
objective is to evaluate the performance and cost of the pooling strategy for detecting the presence and
estimating the prevalence and intensity of infection. The central hypothesis is that pooling provides more
cost-effective decision making for the diagnosis of infection at a reliable sensitivity. The rationale for this
project is that a timely and cost-effective reliable S. haematobium diagnostic strategy will (1) help rapidly
screen samples, particularly in low prevalence settings, and (2) estimate the prevalence and intensity of
infection to evaluate and plan control programs against the disease. Under the first aim, S. haematobium
infection will be examined in different pool sizes, volumes of urine, the intensity of infection, and/or different
diagnostic tests to determine the pool sizes where the parasite can be detected, as well as the volume of urine
and tests that best diagnose the parasite at a reliable sensitivity. For the second aim, the optimal pool size
that can yield the smallest expected number of pooled tests for each study area/village will be determined and
applied for a large-scale epidemiological survey of infection in endemic regions. In the third aim, the
prevalence and intensity of S. haematobium infection will be estimated, individual samples testing results
will be compared, and a cost-benefit analysis for the pooled testing approach will be conducted. This
research proposed is innovative because it will apply an experimental study to validate pool size, the
volume of urine, the intensity of infection and sensitive diagnostic methods for the examination of S.
haematobium infection and define optimal pool size for each region. The pooled urine sample test for
detecting infection and estimation of prevalence and intensity of infection will be applied in a large-scale,
clinical survey for the first time. The cost-benefit analysis will be the first to confirm if pooled testing will
conserve resources for the diagnosis of S. haematobium. The results will clarify when and how pooling
urine samples could translate into important cost-savings in large-scaled epidemiological surveys to
assess the prevalence of infection, gauge PZQ efficacy, and monitor the progress of MDA programs.
