Masterarbeit

Current and future West Nile virus transmission risk in Europe: Environmental niche model integrating climatic, environmental and socioeconomic drivers

Udechukwu Shalom Ebube (03/2024-09/2024)

Betreuer: Stephanie Thomas

West Nile Virus (WNV) is primarily transmitted by Culex pipiens – a mosquito species whose distribution is influenced by a complex interplay of climatic, environmental, and socioeconomic factors. WNV is of significant public health concern as the end of century climate changes make most regions across Europe suitable habitats for the vector as well as provide optimal conditions for WNV transmission. This study employs advanced species distribution modelling (Maxent) to predict the areas suitable for WNV transmission as well as assess WNV transmission risk across various landscapes in continental Europe. Key variables (such as temperature, relative humidity, land cover, and population density), were evaluated using a combination of Jackknife analysis, ENMeval model tuning, and Variance Inflation Factor (VIF) to ensure non-redundant and informative predictors as well as determine the variable contribution to modelling suitable areas for WNV transmission across Europe. To investigate the projected impact of climate change on WNV transmission risk across Europe from 2041 to 2100, this study employed four General Circulation Models (GCMs)—CMCC-ESM2, GISS-E2-1-G, HadGEM3-GC31-LL, and MPI-ESM1-2-HR—under two divergent emission scenarios (SSP245 and SSP585). The results of this study highlights the critical role of climatic variables in driving the expansion of suitable WNV transmission areas, while socioeconomic factors such as urbanization and population density further modulate WNV transmission risk. Findings reveal a significant northward expansion of WNV transmission risk by the end of the century, particularly under the high-emission scenario (SSP585). Under both low and high-emission scenarios (SSP245 and SSP585), southern and central Europe will become hotspots for WNV transmission and northern Europe will become suitable for WNV transmission by the end of the century. Regions rich in bird biodiversity (such as wetlands, river basins and migratory corridors), show heightened WNV transmission risk driven by favourable ecological conditions for both avian hosts (amplifying hosts for WNV) and mosquito vectors. Hence, bird habitats play a critical role in shaping the future landscape of WNV transmission in Europe. The study also underscores the importance of integrating finer-scale socioeconomic data and future climate scenarios to enhance the precision of WNV transmission risk maps. These findings provide a valuable framework for public health interventions, offering insights into targeted vector control and disease prevention strategies. Therefore, as climate change amplifies transmission risk, integrating ecosystem conservation with public health strategies becomes essential. Proactive adaptation and mitigation measures (such as enhanced surveillance, vector control, and climate-resilient policies), are vital to curbing the spread of WNV as well as reducing disease burden in high-risk regions.