Spatial and seasonal patterns of tick distribution and climate-driven shifts in Jiangsu Province, an SFTS-affected region of eastern China

Background Ticks are important vectors of zoonotic pathogens and play a key role in the transmission of severe fever with thrombocytopenia syndrome ( SFTS ) in East Asia. However, a comprehensive understanding of their spatial distribution, seasonal activity, and climate-driven habitat suitability remains limited, particularly at the provincial scale. Methods This study analyzed long-term surveillance data on free-living ticks in Jiangsu Province, an SFTS -affected region in eastern China, from 2019 ~ 2024. Seasonal dynamics and habitat-associated differences were characterized using descriptive statistics. Environmental determinants of tick distribution and projected climate-driven changes in habitat suitability were assessed using an optimized MaxEnt modeling framework. Results A total of 8,860 ticks belonging to seven species across three genera were identified, with Haemaphysalis longicornis (89.1%) and Haemaphysalis flava (9.8%) as the dominant species. Tick density varied seasonally, with post-larval ticks predominating during the April peak and larvae predominating during the September peak. Habitat preference differed between dominant species: H. longicornis was most frequently recorded in rural villages (33.7%) and country parks (18.3%), whereas H. flava was predominantly found in urban parks (24.8%) and forest parks (20.0%). Elevation, maximum temperature of the warmest month (bio5), and precipitation of the driest month (bio14) were key environmental determinants. Under current climatic conditions, highly suitable habitats were concentrated in the southwestern hilly areas. Under the SSP245 scenario (SSP, Shared Socioeconomic Pathway), the area classified as highly suitable using scenario-specific Jenks natural breaks was larger in future projections. Compared with the current scenario-specific high-suitability area, this class increased by 336.5% and 640.3% for H. longicornis and by 91.4% and 118.8% for H. flava during 2021 ~ 2040 and 2041 ~ 2060, respectively. Conclusion Tick distribution in eastern China is strongly shaped by climatic constraints and is projected to undergo spatial reorganization, with larger areas falling into the scenario-specific high-suitability class under future climate scenarios. These findings underscore the importance of integrating climate-sensitive vector surveillance into SFTS prevention strategies within a One Health framework.