Analysis of the spatio-temporal pattern and evolutionary trends of syphilis at township level in Xining City, Qinghai Province, China from 2008 to 2024.

From 2008 to 2024, a total of 15,465 syphilis cases were reported in Xining City, Qinghai Province, yielding an average annual incidence of 4.44 per 10,000 population and a male-to-female ratio of 1.14. Temporal analysis revealed a steadily increasing trend over the 17‑year period, with a consistent seasonal peak in March. Spatial autocorrelation analysis showed significant clustering (global Moran's I = 0.217, P < 0.05), with high‑high clusters concentrated in eastern urban districts and low‑low clusters predominantly in northern areas. The standard deviational ellipse indicated a dominant southeast-northwest directional trend. Spatio‑temporal scan statistics identified four statistically significant high‑incidence clusters, and Kriging interpolation produced a smoothed surface suggesting elevated transmission risk in the eastern and southern townships. These findings demonstrate that syphilis incidence in Xining increased steadily and expanded geographically from urban centers to peripheral areas over the study period, with pronounced spatial and spatio‑temporal heterogeneity. As a hypothesis‑generating descriptive spatial analysis, this study supports enhanced dynamic surveillance, targeted interventions in high‑risk regions, and locally adapted public health measures to strengthen syphilis control.