Many species have experienced dramatic changes in both geographic range and population sizes in recent history. Increases in the geographic range or population size of disease vectors have public health relevance as these increases often precipitate the emergence of infectious diseases in human populations. Accurately identifying environmental factors affecting the biogeographic patterns of vector species is a long-standing analytical challenge, stemming from a paucity of data capturing periods of rapid changes in vector demographics. We systematically investigated the occurrence and abundance of nymphal Ixodes scapularis ticks at 532 sampling locations throughout New York State (NY), USA, between 2008 and 2018, a time frame that encompasses the emergence of diseases vectored by these ticks. Analyses of these field-collected data demonstrated a range expansion into northern and western NY during the last decade. Nymphal abundances increased in newly colonised areas, while remaining stable in areas with long-standing populations over the last decade. These trends in the geographic range and abundance of nymphs correspond to both the geographic expansion of human Lyme disease cases and increases in incidence rates. Analytic models fitted to these data incorporating time, space, and environmental factors, accurately identified drivers of the observed changes in nymphal occurrence and abundance. These models accounted for the spatial and temporal variation in the occurrence and abundance of nymphs and can accurately predict nymphal population patterns in future years. Forecasting disease risk at fine spatial scales prior to the transmission season can influence both public health mitigation strategies and individual behaviours, potentially impacting tick-borne disease risk and subsequently human disease incidence.

在近代历史中，许多物种的地理范围和种群规模都经历了巨大的变化。疾病媒介的地理范围或人口规模的增加具有公共卫生相关性，因为这些增加往往会加速人群中传染病的出现。准确识别影响媒介物种生物地理模式的环境因素是一项长期存在的分析挑战，这是由于缺乏媒介人口统计快速变化时期的数据捕获。我们系统地调查了 2008 年至 2018 年间美国纽约州 (NY) 532 个采样点的若虫肩胛硬蜱的发生情况和丰度，这一时间范围涵盖了由这些蜱传播的疾病的出现。对这些现场收集的数据的分析表明，在过去十年中，范围扩大到了纽约州北部和西部。在过去十年中，新殖民地区的若虫丰度有所增加，而在长期存在的地区则保持稳定。若虫的地理范围和丰度的这些趋势与人类莱姆病病例的地理扩张和发病率的增加相对应。根据这些数据拟合的分析模型结合了时间、空间和环境因素，准确地识别了观察到的若虫出现和丰度变化的驱动因素。这些模型解释了若虫出现和丰度的空间和时间变化，并可以准确预测未来几年若虫的种群模式。 在传播季节之前在精细空间尺度上预测疾病风险可以影响公共卫生缓解策略和个人行为，可能影响蜱传疾病风险以及随后的人类疾病发病率。