West Nile Virus (WNV) is now endemic in many European countries, causing hundreds of human cases every year, with a high spatial and temporal heterogeneity. Previous studies have suggested that spring temperature might play a key role at shaping WNV transmission. Specifically, warmer temperatures in April-May might amplify WNV circulation, thus increasing the risk for human transmission later in the year. To test this hypothesis, we collated publicly available data on the number of human infections recorded in Europe between 2011 and 2019. We then applied generalized linear models to quantify the relationship between human cases and spring temperature, considering both average conditions (over years 2003-2010) and deviations from the average for subsequent years (2011-2019). We found a significant positive association both spatial (average conditions) and temporal (deviations). The former indicates that WNV circulation is higher in usually warmer regions while the latter implies a predictive value of spring conditions over the coming season. We also found a positive association with WNV detection during the previous year, which can be interpreted as an indication of the reliability of the surveillance system but also of WNV overwintering capacity. Weather anomalies at the beginning of the mosquito breeding season might act as an early warning signal for public health authorities, enabling them to strengthen in advance ongoing surveillance and prevention strategies.

西尼罗河病毒（WNV）现在在许多欧洲国家都很流行，每年造成数百例人类病例，并且在时空上具有高度异质性。先前的研究表明，弹簧温度可能在塑造WNV传播中起关键作用。具体而言，4月至5月的高温可能会增加WNV的传播，从而增加今年晚些时候人类传播的风险。为了验证这一假设，我们整理了2011年至2019年间在欧洲记录的人类感染数量的公开数据。然后，我们考虑了两种平均条件（2003年以来， 2010年）以及与随后几年（2011-2019年）平均值的偏差。我们发现空间（平均条件）和时间（偏差）均存在显着的正相关。前者表明通常在较暖的地区WNV循环较高，而后者则暗示了来年春季的春季状况具有预测价值。在上一年中，我们还发现了与WNV检测呈正相关的现象，这可以解释为监视系统可靠性的指标，也可以作为WNV越冬能力的指标。蚊子繁殖季节开始时的天气异常可能是公共卫生部门的预警信号，使他们能够提前加强正在进行的监视和预防策略。前者表明通常在较暖的地区WNV循环较高，而后者则暗示了来年春季的春季状况具有预测价值。在上一年中，我们还发现了与WNV检测呈正相关的现象，这可以解释为监视系统可靠性的指标，也可以作为WNV越冬能力的指标。蚊子繁殖季节开始时的天气异常可能是公共卫生部门的预警信号，使他们能够提前加强正在进行的监视和预防策略。前者表明通常在较暖的地区WNV循环较高，而后者则暗示了来年春季的春季状况具有预测价值。在上一年中，我们还发现与WNV检测呈正相关，这可以解释为监视系统可靠性的指标，也可以作为WNV越冬能力的指标。蚊子繁殖季节开始时的天气异常可能是公共卫生部门的预警信号，使他们能够提前加强正在进行的监视和预防策略。