SCORE Rwanda Mapping Cross-sectional

b>Related studies:

SCORE Five Country CCA Evaluation Cross-sectional
SCORE Burundi Mapping Cross-sectional

Background: The mapping and detection of Schistosoma mansoni infections for national programs has been primarily accomplished using the Kato-Katz (KK) method of microscopic stool examination. This field and laboratory assay detects parasite eggs to estimate prevalence and intensity of infection and ultimately determines the treatment strategy of a program. The KK test requires the collection of stool and, although considered highly specific, is known to be relatively insensitive, especially in areas with low prevalence and intensity. Recently, the development and evaluation of a urine-based, field-friendly, point of contact (POC) assay that detects worm-produced circulating cathodic antigen (CCA) has shown to be relatively specific and highly sensitive across endemic settings, although there have been difficulties in interpreting the so-called trace results lying between clearly negative and clearly positive. Point-of-care circulating cathodic antigen (POC-CCA) is particularly valuable for national programs to evaluate the burden of S. mansoni where regular preventive chemotherapy with praziquantel has been ongoing and there is, consequently, lower endemicity and where program goals may change to elimination as a public health problem.

Objectives: A national school-based reassessment was carried out, using both KK for the detection of S. mansoni eggs and POC-CCA for detection of the worm antigen to determine the feasibility of moving toward schistosomiasis elimination in Rwanda.

The study had the following scientific objectives:

Present the results from the 2014 POC-CCA mapping of 388 schools in Rwanda
Compare the POC-CCA and KK results in 175 schools evaluated by both tests

Methodology

Geographic Location/Study Sites: This study was conducted throughout Rwanda.

Dates of Data Collection: June 2014 to mid-July 2014

Study Design: Country-wide cross-sectional survey

Sampling: A multistage, cross-sectional, cluster-randomized survey was undertaken to estimate prevalence within independent mapping units. Each mapping unit consisted of a number of sectors that were likely to share transmission characteristics based on previous schistosomiasis prevalence data and eco-epidemiological settings. 10 mapping units at low risk and 21 mapping units at high risk of S. mansoni were identified. 13 schools in each high-risk mapping unit and nine schools in each low-risk mapping unit were randomly selected.In addition to the 363 randomly selected schools, 31 proposed sentinel schools were also included. A total of 400 schools were selected for mapping—175 schools were selected for testing with both POC-CCA and KK, 213 were selected for testing with POC-CCA only, and 12 were selected for testing with KK only. However, data were not collected at one school (selected for KK testing only) as there were very few pupils in the target age range of 13-14 years.

Data Collection: Within each school, 50 pupils aged 13-14 years with equal numbers of boys and girls were randomly selected from all pupils in the target age range present in school on the day of sampling. Point-of-care circulating cathodic antigen testing was performed on a single urine sample from each child. Kato-Katz testing used a single stool specimen from each child, processed to provide two slides for microscopy.

ClinEpiDB Data Integration: Data files were provided to ClinEpiDB as cleaned .csv files with all personal identifiers removed. All dates were obfuscated per individual through the application of a random number algorithm that shifted dates no more than seven days to comply with the ethical conduct of human subjects research.

Acknowledgements: We thank the many children, parents, school teachers, and district administrative and health officials who participated in this parasite remapping survey in Rwanda.

Financial Support: SCORE is funded by the Bill & Melinda Gates Foundation through a grant to the University of Georgia Research Foundation (UGARF).

Ethics Statement: This survey was approved by the Institutional Review Board of Imperial College London (St Mary Research Ethics Committee of Imperial College, United Kingdom, 2003/EC No 03.36, R&D No: 03/SB/003E, amended in 2007/REC Ref: AM01, May 2007) and by the Rwanda National Ethics Committee (RNEC) (approval letter no. 261/RNEC/2014).

Last Updated: February 25, 2021The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) supported the mapping of Schistosoma mansoni prevalence in Rwanda to determine the feasibility of moving toward elimination. A national survey of Rwandan schoolchildren used two detection methods: the field standard Kato-Katz (KK) test to detect parasite eggs in stool and the more sensitive circulating cathodic antigen (CCA) rapid assay to detect schistosome antigen in urine. The results indicate that S. mansoni infection is still widespread in Rwanda and prevalence is much underestimated by KK testing.