Effect of Climate Change on West Nile Virus Transmission in Italy: A Systematic Review

Objectives: West Nile Virus (WNV) infection prevalence is increasing in recent years in Europe, particularly in Italy. Such increase has been related to climate and environmental factors. Our review aims to assesstherelation between climate change-related factors and the spread of WNV in Italy.Methods: Weconductedaliterature search across four online databases until 22 January 2025, using as search terms WNV, its vectors, and climate change. Results: Out of 282 unique articles, we included 29 eligible papers published between 2011–2025, most of them assessing distribution of the main WNV vector (Culex pipiens) and epidemiology of the infection in relation to climate/environmental factors. We found a positive strong association of WNV transmission with temperature and agricultural land use. Associations with other environmental variables also emerged, but they were either weak or inconsistent. Conclusion: Despite some inconsistencies in the results, likely due to heterogeneity in study methodologies and interactions of environmental variables, review findings indicate that some climate change-related factors favor WNV spread through its vectors in Italy, in line with exploratory observations obtained on the entire Europe.