Malaria epidemics and its drivers in Uganda in 2022

Abstract Background In Uganda, malaria is a year-round health threat, with transmission intensity varying across regions. Despite ongoing intensified interventions, an unprecedented malaria resurgence in early 2022 affected several districts, prompting a swift response from the National Malaria Cont...

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Main Authors: Maru W. Aregawi, Catherine Maiteki, John C. Rek, Bosco Agaba, Charles Katureebe, Mansour Ranjbar, Chunzhe Zhang, Samson Kiware, Jimmy Opigo
Format: Article
Language:English
Published: BMC 2025-07-01
Series:Malaria Journal
Online Access:https://doi.org/10.1186/s12936-025-05351-4
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author Maru W. Aregawi
Catherine Maiteki
John C. Rek
Bosco Agaba
Charles Katureebe
Mansour Ranjbar
Chunzhe Zhang
Samson Kiware
Jimmy Opigo
author_facet Maru W. Aregawi
Catherine Maiteki
John C. Rek
Bosco Agaba
Charles Katureebe
Mansour Ranjbar
Chunzhe Zhang
Samson Kiware
Jimmy Opigo
author_sort Maru W. Aregawi
collection DOAJ
description Abstract Background In Uganda, malaria is a year-round health threat, with transmission intensity varying across regions. Despite ongoing intensified interventions, an unprecedented malaria resurgence in early 2022 affected several districts, prompting a swift response from the National Malaria Control Division (NMCD). This study aims to assess the scale and underlying causes of the epidemics, quantify the excess cases and deaths, and propose targeted prevention and response strategies. Methods District Health Information System (DHIS2) data from 2017 to 2022 were analysed. A 75th percentile threshold from 2017 to 2021 was used to define true malaria epidemics and compare them to the suspected 2022 epidemic. Excess cases, admissions, and deaths were quantified using area under the curve (AUC) calculations. The level of epidemics was compared across districts with Indoor Residual Spraying (IRS) and Integrated Community Case Management (iCCM) interventions. Precipitation data from multiple sources were used to evaluate rainfall patterns and their impact on malaria epidemics. Results Malaria cases were lowest in 2018 but rose by 31% in 2022 compared to the 2017–2021 3rd quartile. Sixty-four of 146 districts experienced epidemics, with 4 facing persistent epidemics year-round. The 2022 epidemic accounted for 3,379,309 (95% CI 1,553,714, 5,339,709) total excess outpatient malaria cases (confirmed and presumed), 3,018,920 (95% CI 1,321,951, 4,661,201) excess confirmed cases, 149,789 (95% CI 66,029, 235,743) excess inpatient cases. Paradoxically, more epidemics occurred in IRS and iCCM districts. Precipitation patterns were consistent across years and were insignificantly correlated with the 2022 epidemic. Provinces with bimodal rainfall patterns were more prone to epidemics, while unimodal regions had fewer epidemics but higher incidence rates. Rainfall lagged by two months (Lag 2) significantly increased malaria incidence (p < 0.01), with each millimetre of rainfall two months prior associated with 13.4 additional malaria cases. Conclusion The 2022 malaria epidemic affected 64 districts, with over 3.3 million excess cases and nearly 150,000 excess admissions. Gaps in IRS, iCCM, and intervention coverage, along with minimal rainfall correlation and high vulnerability in bimodal regions, highlight the need for better surveillance, sustainable funding, and tailored responses. While climate was not the main driver, programmatic deficiencies, vector composition shift, reduced efficacy of insecticides, coverage and effectiveness of the interventions likely fueled the epidemic. Strengthening epidemic preparedness, response, and investment will be crucial to preventing future outbreaks and achieving long-term malaria control in Uganda.
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institution Kabale University
issn 1475-2875
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publishDate 2025-07-01
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series Malaria Journal
spelling doaj-art-2d9c9a888b8a44189092bd02ee5c0c3d2025-08-20T04:01:47ZengBMCMalaria Journal1475-28752025-07-0124111910.1186/s12936-025-05351-4Malaria epidemics and its drivers in Uganda in 2022Maru W. Aregawi0Catherine Maiteki1John C. Rek2Bosco Agaba3Charles Katureebe4Mansour Ranjbar5Chunzhe Zhang6Samson Kiware7Jimmy Opigo8Global Malaria Programme, Universal Health Coverage/Communicable and Non-Communicable Diseases (UCN) Division, World Health OrganizationMinistry of HealthMinistry of HealthMinistry of HealthWHO Country OfficeWHO Country OfficeGlobal Malaria Programme, Universal Health Coverage/Communicable and Non-Communicable Diseases (UCN) Division, World Health OrganizationIfakara Health InstituteMinistry of HealthAbstract Background In Uganda, malaria is a year-round health threat, with transmission intensity varying across regions. Despite ongoing intensified interventions, an unprecedented malaria resurgence in early 2022 affected several districts, prompting a swift response from the National Malaria Control Division (NMCD). This study aims to assess the scale and underlying causes of the epidemics, quantify the excess cases and deaths, and propose targeted prevention and response strategies. Methods District Health Information System (DHIS2) data from 2017 to 2022 were analysed. A 75th percentile threshold from 2017 to 2021 was used to define true malaria epidemics and compare them to the suspected 2022 epidemic. Excess cases, admissions, and deaths were quantified using area under the curve (AUC) calculations. The level of epidemics was compared across districts with Indoor Residual Spraying (IRS) and Integrated Community Case Management (iCCM) interventions. Precipitation data from multiple sources were used to evaluate rainfall patterns and their impact on malaria epidemics. Results Malaria cases were lowest in 2018 but rose by 31% in 2022 compared to the 2017–2021 3rd quartile. Sixty-four of 146 districts experienced epidemics, with 4 facing persistent epidemics year-round. The 2022 epidemic accounted for 3,379,309 (95% CI 1,553,714, 5,339,709) total excess outpatient malaria cases (confirmed and presumed), 3,018,920 (95% CI 1,321,951, 4,661,201) excess confirmed cases, 149,789 (95% CI 66,029, 235,743) excess inpatient cases. Paradoxically, more epidemics occurred in IRS and iCCM districts. Precipitation patterns were consistent across years and were insignificantly correlated with the 2022 epidemic. Provinces with bimodal rainfall patterns were more prone to epidemics, while unimodal regions had fewer epidemics but higher incidence rates. Rainfall lagged by two months (Lag 2) significantly increased malaria incidence (p < 0.01), with each millimetre of rainfall two months prior associated with 13.4 additional malaria cases. Conclusion The 2022 malaria epidemic affected 64 districts, with over 3.3 million excess cases and nearly 150,000 excess admissions. Gaps in IRS, iCCM, and intervention coverage, along with minimal rainfall correlation and high vulnerability in bimodal regions, highlight the need for better surveillance, sustainable funding, and tailored responses. While climate was not the main driver, programmatic deficiencies, vector composition shift, reduced efficacy of insecticides, coverage and effectiveness of the interventions likely fueled the epidemic. Strengthening epidemic preparedness, response, and investment will be crucial to preventing future outbreaks and achieving long-term malaria control in Uganda.https://doi.org/10.1186/s12936-025-05351-4
spellingShingle Maru W. Aregawi
Catherine Maiteki
John C. Rek
Bosco Agaba
Charles Katureebe
Mansour Ranjbar
Chunzhe Zhang
Samson Kiware
Jimmy Opigo
Malaria epidemics and its drivers in Uganda in 2022
Malaria Journal
title Malaria epidemics and its drivers in Uganda in 2022
title_full Malaria epidemics and its drivers in Uganda in 2022
title_fullStr Malaria epidemics and its drivers in Uganda in 2022
title_full_unstemmed Malaria epidemics and its drivers in Uganda in 2022
title_short Malaria epidemics and its drivers in Uganda in 2022
title_sort malaria epidemics and its drivers in uganda in 2022
url https://doi.org/10.1186/s12936-025-05351-4
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