SCORE Burundi Mapping Cross-sectional

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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 assay that detects worm-produced circulating cathodic antigen (CCA) has shown to be relatively specific and highly sensitive across endemic settings. It 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.

In 2007, mapping of neglected tropical diseases in Burundi found that several of its regions were at risk of schistosomiasis and that S. mansoni was the only human schistosome species that was endemic. A national NTD control program was rolled out in which annual mass drug administration (MDA) of praziquantel targeted school-age children. In 2014, after 6 years of praziquantel annual mass distribution in targeted areas, and sentinel site monitoring data that indicated a decline in prevalence of infection, the national burden of schistosomiasis was reassessed to determine the feasibility of moving toward elimination of S. mansoni in Burundi.

Objective: The objective of this study was to assess the geographical distribution of S. mansoni using a urine-based CCA rapid cassette assay to test a selection of school-age children, complemented by KK stool assays performed in a subset of schools, to determine the feasibility of moving toward schistosomiasis elimination in Burundi.

Methodology

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

Dates of Data Collection: May 2014

Study Design: Cross-sectional study.

Sampling: A multistage, cross-sectional, cluster-randomized survey was undertaken. The country was divided into five eco-epidemiological zones based on previous schistosomiasis risk maps and ecological settings. The five zones were divided into groups of "subzones" to be able to use survey results to define "implementation units" for further drug distribution. The number of primary schools sampled in each subzone was proportional to the total number of communes in each subzone, with communes in high-risk zones allocated proportionally twice as many schools to survey as communes in low-risk zones. Purposive sampling was performed in subzone areas where prevalence of S. mansoni infection was expected to be >10% based on prior years' data; further random sampling was then performed to adjust the number of schools to the number assigned to each zone.

Data Collection: Within each school, 50 students aged 13-14 years were randomly selected from all students in the target age range present in school on the day of sampling. Point-of-care CCA testing was performed on a single urine sample from each child. In sites selected for stool examination, a single stool sample was collected from each of the included children and duplicate slides were prepared using the Kato-Katz technique.

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 acknowledge the contribution from the communities, schoolchildren and their families, school directors, laboratory technicians, and nurses to this study.

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 granted approval by the Ministry of Health in Burundi and the Institutional Review Board of Imperial College London (St Mary Research Ethics Committee of Imperial College, UK, 2003 /EC No 03.36, R&D No: 03/SB/003E, amended in 2007 /REC Ref: AM01, May 2007).

Last Updated: March 5, 2021The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) supported the mapping of Schistosoma mansoni prevalence in Burundi to determine the feasibility of moving toward elimination. A national survey of schoolchildren in Burundi used two detection methods- a single urine-circulating cathodic antigen rapid test and, in a subset of schools, duplicate Kato-Katz slide preparation from a single stool sample. The findings of this nationwide reassessment using the rapid test indicate that Schistosoma infection is still widespread in Burundi, although its average intensity is probably low.