Analysis of the Spatiotemporal Distribution and Evolutionary Trends of Scrub Typhus in Jiangsu Province from 2006 to 2023.

Abstract

Objective: This study aims to analyze the epidemiological characteristics, spatial and temporal distribution patterns, and trends in the evolution of scrub typhus (ST) in Jiangsu Province from 2006 to 2023. Scrub typhus was chosen for this study due to its increasing incidence in Jiangsu Province, its substantial health burden on rural populations, and its relevance as a vector-borne disease influenced by environmental and seasonal factors.

Methods: Data on ST cases in Jiangsu Province from 2006 to 2023 were obtained from the China Disease Control and Prevention Information System. Descriptive statistics were used to summarize the overall epidemiological trends. Spatial autocorrelation analysis (Global and Local Moran's I) assessed the overall and local distribution patterns of ST cases. while spatial-temporal hotspot analysis identified regions with significant clustering of cases over time, providing insights into potential high-risk areas.

Results: A total of 16,998 ST cases were reported in Jiangsu Province, with an average annual incidence rate of 1.13 per 100,000. The gender distribution showed a male-to-female ratio of 1:1.20. The ages of affected individuals ranged from 3 months to 97 years, with a mean age of 60 years. Farmers represented the largest occupational group, accounting for 84.68% of the cases. The incidence rate showed a significant upward trend (χ²trend = 8484.517, p < 0.001). Peak incidence occurred primarily between October and November. The global Moran's I index ranged from 0.071 to 0.345. Local autocorrelation analysis revealed that Yancheng and Nantong cities were high-high clustering areas. Spatial-temporal hotspot analysis revealed that hotspots were predominantly located in the northern and central regions of Jiangsu, while the southern region was identified as a cold spot. These hotspots displayed oscillating patterns, with new hotspots emerging in specific areas. Standard deviation ellipse analysis indicated that the epidemic spread continued to expand along the north-south axis, while the east-west axis showed relative stability. Spatial-temporal scanning analysis identified four high-incidence spatial-temporal clustering zones.

Conclusion: The incidence of ST in Jiangsu Province exhibited a significant upward trend, with distinct seasonal peaks between October and November. The epidemic demonstrated a pronounced transmission along the north-south axis, spatial-temporal clustering, and a shifting center of gravity. It is recommended to strengthen surveillance in high-risk areas and implement targeted prevention and control measures during high-risk seasons, particularly for vulnerable populations, to effectively curb the spread of the epidemic.