Abstract
OBJECTIVE: To determine the current and future suitable areas of Rickettsia japonica, and to provide a reference for preventing its outbreak and spread. METHODS: Based on the geographic distribution of R. japonica and Haemaphysalis longicornis overlapping data points and information on 56 climatic factors, we utilized the Maxent model to estimate suitable areas for R. japonica in Asian adjacent Regions and China. Model parameter adjustments and the construction of receiver operating characteristic curves were conducted using R 4.3.0 software. RESULTS: Average precipitation in June (prec6, 28.2%), Temperature Seasonality (bio4, 9.8%) and the minimum temperature in August (tmin8, 9.2%) contributed most to the distribution of R. japonica. The performance metrics for the Maxent model in predicting the distribution of R. japonica are as follows: the Area Under the Curve (AUC) is 0.990, the True Skill Statistic (TSS) is 0.857, and the Kappa statistic is 0.763. Under current climatic conditions, the Asian and adjacent space medium and highly suitable areas for R. japonica are estimated to be 176.78 × 10(4) km(2) and 95.13 × 10(4) km(2), respectively. The highly suitable areas for R. japonica were mainly distributed in east and south Asia. In China, the high suitability areas are mainly distributed in the southeast coastal areas and the Qinling Mountains and Huai River cities. Under future climatic conditions, the Asian and adjacent regions maximum area change rate of R. japonica increased by 118.65%, and that of China increased by 50.42%. Meanwhile, the suitable areas of R. japonica gradually expanding northward in China. CONCLUSION: Under global climate change, the suitable area of R. japonica is generally increasing, with a northward shift observed in China. Governments should strengthen monitoring, risk assessment, and response strategies in highly suitable regions, while also preventing the invasion of R. japonica from external source.