Understanding the environmental drivers of West Nile Virus (WNV) emergence in Europe

WNV is a mosquito-borne pathogen with continuous geographic expansion in Eurasia. Its ecology in Europe is still poorly understood due to the high viral diversity and the complexity of its cycle. Several vertebrate and mosquito species are involved in WNV's dynamics, although a limited set are playing a major role. Moreover, the interplay among the many biotic and abiotic factors driving WNV amplification is complex. To shed light on the dense relationships among WNV emergence and environmental drivers is therefore essential. The aim of this study was to analyze the relationships among WNV human cases in Europe (2010-2012; ECDC) and a series of climatic and environmental parameters characterizing the areas with WNV cases. The modeling procedure has been carried out using WNV incidence as response variable and a complete set of climatic and environmental parameters as predictors. GLMs were implemented to examine the relationships between WNV incidence and the predictors. Best models were identified using AIC model selection. Preliminary results showed that WNV incidence is positively influenced by early summer temperature anomalies while spring precipitation anomalies have negative effects. Besides, the most important environmental parameters include the presence of populated forest, irrigated croplands and mosaic grasslands. Several other parameters are currently under examination. In conclusion, results showed how using a multi-set of predictors within a robust modeling framework could provide a better understanding on the several parameters creating the favorable condition for WNV spill over