Performance of Tests for Schistosoma Haematobium Diagnosis

Schistosoma Haematobium Diagnostic Test Performance in the Elimination Setting Pemba, Tanzania

Urogenital schistosomiasis caused by infection with the blood fluke Schistosoma haematobium is a debilitating disease. The World Health Organization (WHO) has set the goal to eliminate schistosomiasis as a public health problem globally by 2030 and to interrupt transmission in selected areas. Many years of control interventions and mass drug administration have reduced substantially the prevalence and infection intensities in several areas. In areas with an infection prevalence <10%, the WHO suggests to continue population preventive chemotherapy with praziquantel at the same or reduced frequency, or to use a clinical approach of test-and-treat. In areas that have achieved interruption of transmission, elimination needs to be validated and post-elimination surveillance be implemented.

For determination of infection prevalence thresholds, for test-and-treat, for validation of elimination and for pre- and post-elimination surveillance, reliable diagnostic tools are needed.

In a single-centre study conducted in Pemba, United Republic of Tanzania, the investigators aim to assess the accuracy and performance of standard and new diagnostic tests for S. haematobium diagnosis for use in elimination settings.

The primary objective of the study is to assess the sensitivity and specificity of all investigated diagnostic tests, using the S. haematobium egg count results of five urine filtrations conducted on five urine samples collected over five consecutive days as reference test.

Secondary objectives are:

• To assess the sensitivity and specificity of all investigated diagnostic tests, using latent class analyses.
• To assess the sensitivity and specificity of all investigated diagnostic tests, in relation to S. haematobium infection intensity, calculated as mean egg count derived from the egg counts in five urine samples collected over 5 consecutive days.
• To assess the sensitivity and specificity of all investigated diagnostic tests, in relation to S. haematobium infection intensity, calculated from the egg counts of the urine sample that was analysed with the respective test and urine filtration.
• To assess the sensitivity and specificity of all investigated diagnostic tests, using the results of the up-converting reporter particle-lateral flow circulating anodic antigen assay (UCP-LF CAA) as reference test.
• To assess the sensitivity and specificity of all investigated molecular diagnostic tests, using the results of the qPCR as reference test.
• To assess the cost and time needed for the implementation of single or multiple-throughput tests.

Our study will evaluate the accuracy and performance of diagnostic tests, in a formerly highly endemic setting that is now approaching elimination (Pemba), and will hence provide important information about which tests can be recommended for threshold determination, and test-and-treat and surveillance.

Inclusion Criteria:

Subjects fulfilling all of the following inclusion criteria are eligible for the initial screening:

• Attendance of grade 3, 4, 5, or 6 in study school
• Randomized to participate in initial screening
• Written informed consent signed by the parents
• Written assent signed by the participant if aged12-17 years old

Subjects fulfilling all of the following inclusion criteria are eligible for the diagnostic study:

• Attendance of grade 3, 4, 5, or 6 in study school
• Randomized to participate in initial screening
• Written informed consent signed by the parents
• Written assent signed by the participant if aged12-17 years old
• S. haematobium-positive urine filtration result in initial screening OR
• S. haematobium-negative urine filtration result in initial screening, but randomized for participation in diagnostic study

Exclusion Criteria:

The presence of any one of the following exclusion criteria will lead to the exclusion of the subject in the initial screening:

• Not attending any study school
• Not attending grade 3, 4, 5 or 6
• Not randomized to participate in initial screening
• No written informed consent signed by the parents submitted
• No written assent signed by the participant if aged12-17 years old submitted
• S. haematobium-negative urine filtration result in initial screening, and not randomized for participation in diagnostic performance study
• Clinical significant sever disease

The presence of any one of the following exclusion criteria will lead to the exclusion of the subject in the diagnostic study:

• Not attending any study school
• Not attending grade 3, 4, 5 or 6
• Not randomized to participate in initial screening
• No written informed consent signed by the parents submitted
• No written assent signed by the participant if aged12-17 years old submitted
• S. haematobium-negative urine filtration result in initial screening, and not randomized for participation in diagnostic performance study
• Clinical significant sever disease