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. 2025 Oct 7;113(6):1256-1266.
doi: 10.4269/ajtmh.25-0031. Online ahead of print.

Quantifying the Lagged Effects of Climate Variables on Malaria Risk in Eastern Uganda

Sooyoung Kim  1 , Betty Nabukeera  2 , Yehu Taremwa  2 , Maureen Ng'etich  3 , Flavian Otieno  3 , Steve Cygu  4 , Dan Kajungu  2   4 , Agnes Kiragga  3 , Yesim Tozan  5
Affiliations

Quantifying the Lagged Effects of Climate Variables on Malaria Risk in Eastern Uganda

Sooyoung Kim et al. Am J Trop Med Hyg. .

Abstract

Climate change is anticipated to significantly affect malaria transmission. Previous research has shown lagged, nonlinear associations between climate variables and malaria risk, with highly context-specific exposure-lag-response relationship. Using weekly malaria case data collected between July 2018 and February 2023 from a health facility within the Iganga-Mayuge Health and Demographic Surveillance System site in Uganda and remotely sensed temperature and rainfall data, we quantified the associations between temperature and rainfall and risk of developing symptomatic malaria using a distributed lag nonlinear model. Furthermore, we investigated whether these associations varied by age group. Our analysis revealed a lag of 2 to 8 weeks between exposure to rainfall exceeding 200 mm/week and a significant increase in the risk of developing symptomatic malaria; no statistically significant lagged association was found with temperature. Additionally, the risk in school-aged children was less sensitive to climate variables compared with the other age groups. Rainfall was found to be associated with an increased risk at a lag of 2 months at the study site. This finding provides valuable guidance for local health authorities in determining the optimal timing for preventive interventions and in preparing for the anticipated rise in demand for malaria case management. The observed variations in the risk of developing symptomatic malaria across different age groups highlight the need for targeted interventions tailored to specific populations. Overall, the significant associations between climate variables and malaria risk underscore the importance of context-specific, adaptive malaria control strategies, complemented by broader efforts to mitigate climate change.

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Conflict of interest statement

Disclosures: The Iganga-Mayuge HDSS longitudinal cohort study was granted ethical approval by the research and ethics committees at the Makerere University School of Public Health and the Uganda National Council for Science and Technology. Each participant provided written informed consent after the interviewer had explained to them individually the study purpose, risks, benefits, compensation and voluntary participation and options for withdrawal from the study. Privacy was ensured during interviews, with one participant in a room at a time. Confidentiality was maintained during data storage, and this paper does not include personal identifiers that can be used to track participants.

Figures

Figure 1.
Figure 1.
Weekly facility-based reported malaria cases and climate variables (rainfall and temperature based on ERA5 daily climate data) at the Iganga-Mayuge Health and Demographic Surveillance System (HDSS) site, Uganda, July 2018–February 2023.
Figure 2.
Figure 2.
Weekly reported malaria cases by age group at the Iganga-Mayuge Health and Demographic Surveillance System (HDSS) site, Uganda, July 2018–February 2023.
Figure 3.
Figure 3.
Three-dimensional (A and B) and 2-dimensional (C and D) plots summarizing the relative risk of malaria across varying rainfall (x axis, A and C) and temperature (x axis, B and D) values at different lags (y axis). Reference values for rainfall and maximum temperature correspond to the lowest observed values during the study period.
Figure 4.
Figure 4.
Relative risk (RR; y axis) of malaria across the range of observed total rainfall and maximum temperature values (x axis) at different lags. Reference values for rainfall and maximum temperature correspond to the lowest observed values during the study period.
Figure 5.
Figure 5.
Relative risk (RR; y axis) of malaria across the range of observed minimum temperature values (x axis) at different lags. The reference value for minimum temperature is 20°C.
Figure 6.
Figure 6.
Relative risk of malaria by age group across the observed range of weekly mean daily maximum temperature (Lag = 0 weeks).
Figure 7.
Figure 7.
Relative risk of malaria by age group across the observed range of weekly total rainfall (Lag = 4 weeks).
See this image and copyright information in PMC

References

    1. World Health Organization, 2023. World Malaria Report 2023. Available at: https://www.who.int/publications/i/item/9789240086173. Accessed May 4, 2024.
    1. Oladipo HJ, Tajudeen YA, Oladunjoye IO, Yusuff SI, Yusuf RO, Oluwaseyi EM, AbdulBasit MO, Adebisi YA, El-Sherbini MS, 2022. Increasing challenges of malaria control in sub-Saharan Africa: Priorities for public health research and policymakers. Ann Med Surg (Lond) 81: 104366. - PMC - PubMed
    1. Yeka A, et al. , 2012. Malaria in Uganda: Challenges to control on the long road to elimination: I. Epidemiology and current control efforts. Acta Trop 121: 184–195. - PMC - PubMed
    1. Tusting LS, et al. , 2016. Why is malaria associated with poverty? Findings from a cohort study in rural Uganda. Infect Dis Poverty 5: 78. - PMC - PubMed
    1. Kooko R, Wafula ST, Orishaba P, 2023. Socioeconomic determinants of malaria prevalence among under five children in Uganda: Evidence from 2018-19 Uganda Malaria Indicator Survey. J Vector Borne Dis 60: 38–48. - PubMed

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