Spatiotemporal patterns and incidence trends of other infectious diarrhea in Qinghai Province, 2009–2023: a surveillance-based analysis

Background While other infectious diarrhea (OID) has a persistent increase in occurrence throughout China, its epidemiological traits in high-altitude regions are inadequately studied. Qinghai Province, situated on the Tibetan Plateau, offers an essential context for analyzing OID patterns under unique climatic conditions. Methods We examined reported incidence data for OID in Qinghai Province from 2009 to 2023. Temporal trends were evaluated by Joinpoint regression and Seasonal-Trend decomposition using Loess (STL) decomposition, while methods including spatial autocorrelation, cluster analysis, hotspot analysis, the Gravity center shift model, and standard deviation ellipse were utilized. Results Between 2009 and 2023, there were 58,717 reported instances of OID, including one death in 2020. The overall incidence rate increased significantly, with an average annual percent change (AAPC) of 7.11% (95% CI: 2.03%−13.43%, p = 0.008). The escalation was more pronounced in females (AAPC = 9.11%, 95% CI: 1.03%−17.83%, p = 0.026) than in males (AAPC = 5.94%, 95% CI: −2.26% to 14.83%, p = 0.160). Substantial regional variations were apparent; although the highest incidence rates were located in Xining City and Haidong City, the fastest expansion transpired in Haibei City (AAPC = 15.71%, p < 0.001). A bimodal age distribution was discovered, with the highest incidence among children under 5 years (890.45 per 100,000) and the older adults, and the fastest escalation observed among young children. Spatial analysis indicated substantial positive spatial autocorrelation, with Moran's I values ranging from 0.404 to 0.643 (all p < 0.001), pinpointing Xining City and Haidong City as the principal high-high cluster areas encompassing eight counties. Standard deviational ellipse analysis revealed a primary clustering region centered around Xining and Haidong with a dominant northeast-southwest spatial axis. The incidence centroid remained consistently concentrated in the eastern area south of Xining city, exhibiting a three-phase migration pattern of stable fluctuation, significant southwestward shift, and gradual return to the core area over the study period. Conclusions The incidence of OID in Qinghai Province has markedly risen, exhibiting distinct spatial clustering and demographic variations. These ecological findings suggest priority regions (Xining, Haidong) and populations (children under five, the older adults) for targeted public health interventions and warrant further investigation into environmental and healthcare-related determinants.