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Adherence to solar disinfection water treatment reduces diarrheal incidence among children in Malawi: a secondary analysis of a cluster quasi-experimental study

Adherence to solar disinfection water treatment reduces diarrheal incidence among children in Malawi: a secondary analysis of a cluster quasi-experimental study
Adherence to solar disinfection water treatment reduces diarrheal incidence among children in Malawi: a secondary analysis of a cluster quasi-experimental study
Background: diarrheal diseases are a leading cause of morbidity and mortality among children under-five in low-income regions. This study evaluated the effectiveness of household (Hh) Solar Disinfection (SODIS) in reducing diarrhoeal incidence among under-five children.

Methods: we conducted a secondary analysis based on a cluster quasi-experimental trial conducted in Chikwawa district Malawi (March 2019 to March 2020) involving 369 children from 271 Hh in a control group and two intervention groups: one using 20 L transparent polypropylene SODIS buckets (336 children, 258 Hh) and another using a combined 20 L transparent polypropylene SODIS bucket and cloth filter system (380 children, 264 Hh). Variables of interest included household water sources, child age, sex, rotavirus vaccination, SODIS adherence, and the outcome variable was diarrhoeal incidence. Descriptive statistics, Chi-square tests, Kruskal-Wallis tests, and Poisson regression with robust standard errors were used as statistical methods in Stata 17.

Results: the study revealed an overall incidence of 2 cases per child year at risk and decreased over time. Households using SODIS buckets had an 88% reduction in diarrhoeal incidence, adjusted Incidence Rate Ratios (IRRs) 0.12 (95% CI: 0.04, 0.23); those using the combined SODIS bucket and cloth filter had a 70% reduction, adjusted IRR 0.30 (95% CI: 0.18, 0.50). SODIS adherence significantly impacted diarrhoeal reduction; high SODIS adherent households saw a 90% reduction in incidence compared to low adherent ones, adjusted IRR of 0.13 (95% CI: 0.02, 0.81). Those with medium adherence did not experience a significant reduction.

Conclusion: the research suggests that SODIS is an effective method to reduce the incidence of diarrhoea in children living in the Chikwawa district. Its success depended on how well people followed SODIS practices; efforts to increase adoption and adherence should be considered.

Humans, Malawi/epidemiology, Diarrhea/epidemiology, Water Purification/methods, Incidence, Child, Preschool, Disinfection/methods, Male, Female, Infant, Sunlight, Cluster Analysis, Family Characteristics
1477-8920
1255-1268
Luwe, Kondwani
3fadef21-1d90-446b-a8e2-e493d74f23bf
Lungu, Kingsley
6da77268-9ee1-48d5-b5ab-2986bc3ec009
Morse, Tracy
605ddfed-c437-4858-a51f-1170d5d5b003
McGuigan, Kevin G
9338997c-a40c-4886-8e0c-42ad3014a205
Conroy, Ronan M
c6bdbe65-3907-43e9-9143-53d3c67e1d37
Buck, Lyndon
49b03b09-a98b-4edb-9b14-f5a8f6363971
Sambala, Evanson Z
12f4f18c-1e3f-408b-a69e-c5218c70f5e7
Luwe, Kondwani
3fadef21-1d90-446b-a8e2-e493d74f23bf
Lungu, Kingsley
6da77268-9ee1-48d5-b5ab-2986bc3ec009
Morse, Tracy
605ddfed-c437-4858-a51f-1170d5d5b003
McGuigan, Kevin G
9338997c-a40c-4886-8e0c-42ad3014a205
Conroy, Ronan M
c6bdbe65-3907-43e9-9143-53d3c67e1d37
Buck, Lyndon
49b03b09-a98b-4edb-9b14-f5a8f6363971
Sambala, Evanson Z
12f4f18c-1e3f-408b-a69e-c5218c70f5e7

Luwe, Kondwani, Lungu, Kingsley, Morse, Tracy, McGuigan, Kevin G, Conroy, Ronan M, Buck, Lyndon and Sambala, Evanson Z (2025) Adherence to solar disinfection water treatment reduces diarrheal incidence among children in Malawi: a secondary analysis of a cluster quasi-experimental study. Journal of Water and Health, 23 (10), 1255-1268, [jwh2025092]. (doi:10.2166/wh.2025.092).

Record type: Article

Abstract

Background: diarrheal diseases are a leading cause of morbidity and mortality among children under-five in low-income regions. This study evaluated the effectiveness of household (Hh) Solar Disinfection (SODIS) in reducing diarrhoeal incidence among under-five children.

Methods: we conducted a secondary analysis based on a cluster quasi-experimental trial conducted in Chikwawa district Malawi (March 2019 to March 2020) involving 369 children from 271 Hh in a control group and two intervention groups: one using 20 L transparent polypropylene SODIS buckets (336 children, 258 Hh) and another using a combined 20 L transparent polypropylene SODIS bucket and cloth filter system (380 children, 264 Hh). Variables of interest included household water sources, child age, sex, rotavirus vaccination, SODIS adherence, and the outcome variable was diarrhoeal incidence. Descriptive statistics, Chi-square tests, Kruskal-Wallis tests, and Poisson regression with robust standard errors were used as statistical methods in Stata 17.

Results: the study revealed an overall incidence of 2 cases per child year at risk and decreased over time. Households using SODIS buckets had an 88% reduction in diarrhoeal incidence, adjusted Incidence Rate Ratios (IRRs) 0.12 (95% CI: 0.04, 0.23); those using the combined SODIS bucket and cloth filter had a 70% reduction, adjusted IRR 0.30 (95% CI: 0.18, 0.50). SODIS adherence significantly impacted diarrhoeal reduction; high SODIS adherent households saw a 90% reduction in incidence compared to low adherent ones, adjusted IRR of 0.13 (95% CI: 0.02, 0.81). Those with medium adherence did not experience a significant reduction.

Conclusion: the research suggests that SODIS is an effective method to reduce the incidence of diarrhoea in children living in the Chikwawa district. Its success depended on how well people followed SODIS practices; efforts to increase adoption and adherence should be considered.

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More information

Accepted/In Press date: 12 September 2025
e-pub ahead of print date: 19 September 2025
Published date: 1 October 2025
Keywords: Humans, Malawi/epidemiology, Diarrhea/epidemiology, Water Purification/methods, Incidence, Child, Preschool, Disinfection/methods, Male, Female, Infant, Sunlight, Cluster Analysis, Family Characteristics

Identifiers

Local EPrints ID: 506235
URI: http://eprints.soton.ac.uk/id/eprint/506235
ISSN: 1477-8920
PURE UUID: 4317e070-6efe-4a59-a365-b9623449f9e3
ORCID for Lyndon Buck: ORCID iD orcid.org/0000-0001-7046-5805

Catalogue record

Date deposited: 30 Oct 2025 17:50
Last modified: 05 Nov 2025 03:14

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Contributors

Author: Kondwani Luwe
Author: Kingsley Lungu
Author: Tracy Morse
Author: Kevin G McGuigan
Author: Ronan M Conroy
Author: Lyndon Buck ORCID iD
Author: Evanson Z Sambala

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