Background

Schistosomiasis (SCH) or bilharzia (also known as kichocho in the Kiswahili language) is a disease caused by parasitic worms found in freshwater snails, and affects over 250 million people worldwide. The worms infect people by penetrating through the skin during daily routine activities in freshwater bodies (such as in rivers or lakes). The adult worms live in the blood vessels around the urinary bladder or the intestines, where they lay eggs that are passed out in urine or faeces. Currently, bilharzia is detected by examination of faeces and/or urine samples under the microscope to check for eggs. Where infection has been controlled, determining the infection status of individuals by use of a microscope becomes difficult because of fewer number of eggs. Poor detection of infection can result in premature stopping of control activities and resumption of disease. To support programmes for control and/ or elimination of bilharzia, new and better tests for detecting the disease are needed. To address this gap, the Foundation for Innovative New Diagnostics (FIND) together with other partners are developing a new test to be used at the location the patient is presenting with disease with quick results known as the SCH CAA RDT.

What questions are we trying to answer?

Most of the development of the SCH CAA RDT has been done using stored frozen blood samples, but before the new test is cleared for manufacturing, it needs to be tested using fresh samples. Results from this evaluation study, to be led by KEMRI, will allow further improvements of the new test to ensure it meets the recommended standards.

Where is the study taking place, how many people does it involve and how are they selected?

The study will be carried out in Kwale and Siaya counties where both the urogenital (disease affects the urinary and reproductive areas) and intestinal forms of the disease occur, respectively.  In each county, one village will be selected and 350 people (aged above 5 years and above) will be included in the study. In addition, one village in Kiambu County, where the disease is not found has been selected and samples will be collected from 76 participants to further evaluate performance of the test among people without the disease.

What does the study involve for those who are taking part?

After participants agree to participate, stool and urine samples will be collected from them, each day for three consecutive days, to find out whether they have bilharzia. In addition, 5 ml of blood will be collected from each participant on the first day, as well as a tiny amount of blood from the finger. All participants found with bilharzia and other intestinal worms will be treated.

What are the risks and benefits involved in taking part?

Participants may experience minor but temporal pain and discomfort during the collection of blood, temporal change in colour on the skin and swelling of the vein. Very rarely, some individuals may experience a sudden drop-in heart rate and blood pressure, leading to profuse sweating, nausea and on rare occasions, fainting. Some participants may find collection of stool and urine samples to be uncomfortable. Treatment will be offered to those individuals found to be infected with bilharzia and other intestinal worms. Individuals might experience some side effects upon treatment with praziquantel, however, those are mild and temporal.

How will the study benefit society?

Treatment of infected individuals will also benefit other villagers, as it will contribute to reducing spread of the disease. Community members will also be educated/sensitized on how to control and prevent bilharzia. In the longer-term, the study will have contributed to the development of a new test which will support control efforts and improved identification of villages requiring treatment.

When does the study start and finish?

Sample collection and field evaluation of the new test is expected to begin in August 2020 and last for five months. Data entry, data analysis and report writing is expected to be finalized by February 2021.

Current methods for diagnosis of schistosomiasis (SCH) rely on detection of parasite eggs in stool or urine by microscopy. These methods are simple but have reduced sensitivity in low prevalence settings in addition to being laborious, time-consuming, as well as the requirement to have expert microscopists to identify parasite eggs accurately. Improved methods of detecting SCH have been or are being developed, but in their current format, are not field-friendly. To support national SCH programmes to reach elimination target as defined by WHO, new and better diagnostic tests need to be developed. To address this gap, the Foundation for Innovative New Diagnostics (FIND) in collaboration with WHO, Mologic and Leiden University Medical Center (LUMC) are developing a new point-of-care (POC) rapid diagnostic test (RDT) (known as the SCH CAA RDT) that aims to support national control programmes to monitor the impact of treatments, and for reassessment mapping. So far, the prototype has only been evaluated using stored serum samples from SCH-infected individuals. Therefore, the aim of this study, to be led by KEMRI, is to evaluate the performance of the prototype RDT using freshly collected samples from SCH infected and non-infected individuals living in Kenya. The study will be carried out in Kwale and Siaya counties where previous studies have found relatively moderate levels of SCH infections. The two sites have been selected, based on the presence of only S. haematobium or only S. mansoni infections, respectively. In each county, one village will be selected and 350 inhabitants (aged ≥5 years and permanent residents in the study area) will be included. In addition, Kiambu County has been selected as a non-endemic area to ensure that a negative “control” pool of samples is made available to evaluate the specificity of the prototype. One village will be selected and 76 inhabitants (aged ≥5 years and permanent residents in the study area) will be included in the study. Individuals will be consecutively enrolled in the study. Stool and urine samples will be collected from participants, each day for three consecutive days, to find out whether they are infected with SCH. In addition, 5 ml venous blood will be drawn from each participant on the first day of sample collection, as well as a 50µl finger prick blood sample. All participants found positive for SCH and soil-transmitted helminths (STH) (also commonly known as intestinal worms) will be treated at the end of the study following national treatment guidelines.

The performance of the SCH CAA prototype RDT will be compared to that of those diagnostic tests currently recommended by the WHO, namely microscopy-based tests. Results from this evaluation study will allow further optimization of the prototype RDT to ensure that it meets the targets defined in the target product profile (TPP). It is envisaged that the RDT will support national SCH programmes to monitor the impact of public health interventions such as mass drug administration (MDA) campaigns as well as for reassessment mapping.