Climate Drivers of Malaria Transmission Seasonality and Their Relative Importance in Sub‐Saharan Africa. (29th January 2023)

• Record Type: Journal Article
• Authors: Yamba, Edmund I.; Fink, Andreas H.; Badu, Kingsley; Asare, Ernest O.; Tompkins, Adrian M.; Amekudzi, Leonard K.
• Is Part Of: GeoHealth. Volume 7:Number 2(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-01-29
• Subjects: climate -- drivers -- seasonal -- malaria -- transmission -- relative; Environmental health -- Periodicals; Electronic journals; Periodicals; 616.98
• DOI: 10.1029/2022GH000698
• Languages: English
• ISSNs: 2471-1403

Abstract

Abstract: A new database of the Entomological Inoculation Rate (EIR) was used to directly link the risk of infectious mosquito bites to climate in Sub‐Saharan Africa. Applying a statistical mixed model framework to high‐quality monthly EIR measurements collected from field campaigns in Sub‐Saharan Africa, we analyzed the impact of rainfall and temperature seasonality on EIR seasonality and determined important climate drivers of malaria seasonality across varied climate settings in the region. We observed that seasonal malaria transmission was within a temperature window of 15°C–40°C and was sustained if average temperature was well above 15°C or below 40°C. Monthly maximum rainfall for seasonal malaria transmission did not exceed 600 in west Central Africa, and 400 mm in the Sahel, Guinea Savannah, and East Africa. Based on a multi‐regression model approach, rainfall and temperature seasonality were found to be significantly associated with malaria seasonality in all parts of Sub‐Saharan Africa except in west Central Africa. Topography was found to have significant influence on which climate variable is an important determinant of malaria seasonality in East Africa. Seasonal malaria transmission onset lags behind rainfall only at markedly seasonal rainfall areas such as Sahel and East Africa; elsewhere, malaria transmission is year‐round. High‐quality EIR measurements can usefully supplement established metrics for seasonal malaria. The study's outcome is important for the improvement and validation of weather‐driven dynamical mathematical malaria models that directly simulate EIR. Our results can contribute to the development of fit‐for‐purpose weather‐driven malaria models to support health decision‐making in the fight to control or eliminate malaria in Sub‐Saharan Africa. Plain Language Summary: In this study, we provide evidence of the direct link between climate variables and the risk of humans to infectious mosquito bites. The study informs our understanding of the connection between climate variables and both the malaria vector and parasite biology and how that translates into malaria seasonality in Sub‐Saharan Africa. Information from this study is key for the improvement and validation of weather‐driven dynamical malaria models that directly simulates metrics that connects climate to malaria transmission. Our findings provide an understanding of geographical heterogeneous malaria risk from climate effect and support future malaria modeling and forecasting efforts. The study also supplements previous works describing clinical patterns of malaria infection and morbidity. Taking into account the seasonality of malaria management, findings in this study could lead to significant public health advantages by assisting in determining when, where, and how to use vector and parasite control strategies. It can, therefore, help stakeholders establish a robust framework for monitoring, forecasting and control of malaria. Key Points: In Sub‐Saharan Africa, seasonal malaria transmission is sustained at temperatures well above 15°C or below 40°C with maximum monthly rainfall not exceeding 600 mm Rainfall and temperature are significant drivers of malaria seasonality in all parts of Sub‐Saharan Africa except in west Central Africa Malaria transmission onset lags behind rainfall only at markedly seasonal rainfall areas, otherwise, malaria transmission is year‐round