Assessing the Impact of Climate Change on Malaria Transmission in Kenya's Lake Victoria Basin

In large parts of Africa, including the Lake Victoria Basin, malaria continues to be a major public health challenge, causing significant morbidity and mortality despite advancements in treatment and prevention. Climate change has the potential to exacerbate the problem because the disease vectors depend on non-permanent open water bodies for mosquito breeding and certain temperature thresholds for larval development. Climate-induced changes in hydrology, such as shifts in the timing and intensity of rainy seasons, combined with rising temperatures, may extend malaria risk to higher altitudes and new areas, necessitating preventive measures to counteract new transmission patterns.

In this study, we assess the impact of climate change on malaria transmission in the Lake Victoria Basin in Kenya, focusing on changes in mosquito breeding sites and temperature. To improve the representation of the breeding sites, the malaria transmission model VECTRI was coupled with the eco-hydrological model SWIM, which was enhanced with a pond module to capture non-permanent water bodies. We evaluated the model performance using Sentinel-1 satellite-derived water occurrence data and malaria incidence data obtained from health records in Kenya's Lake Victoria basin. To obtain high-resolution insights into the future of malaria transmission, projections were made using an ensemble of nine CMIP6 GCMs, downscaled to 1 km using the CHELSA downscaling method, covering several SSP scenarios.

The results of the coupled approach were promising in simulating water occurrence patterns and malaria incidence, demonstrating its potential as a valuable tool for predicting the effects of climate change on malaria transmission by capturing the interplay between climate, hydrology, and malaria dynamics. This research can guide the development of targeted public health interventions and adaptation strategies to mitigate the effects of climate change in malaria-endemic and at-risk regions.