Objective To detect global infectious disease events occurring outside mainland China in October 2025 and assess the importation risk to China and international travel risk.

Methods Utilizing open-source intelligence on the internet, this study conducts event-based surveillance of priority infectious diseases and adopts the risk matrix methodology to build an indicator system by integrating disease-, country- and event-specific indicators in terms of transmission likelihood and severity of consequences in order to assess the risk of the importation and the risk of international travel.

Results In October 2025, 18 infectious diseases were detected to form events or outbreaks in 38 countries worldwide. In terms of importation risk to China, there are 0 high-risk events and 16 medium-risk events; in terms of international travel risk, there are 6 high-risk events and 30 medium-risk events.

Conclusion Regarding overseas travel risks, it is advised that travelers pay close attention to dengue fever in Colombia, Bangladesh, Kiribati, and Samoa, and chikungunya fever in Brazil and Bangladesh. Compared to September, in October, special attention should continue to be paid to dengue fever in Colombia, Bangladesh, Kiribati, and Samoa, as well as chikungunya fever in Brazil and Bangladesh. General attention should also be paid to diphtheria in Mauritania, Mali, and South Africa; pertussis in New Zealand; dengue fever in Sri Lanka, Pakistan, and Mexico; SFTS(Severe fever with thrombocytopenia syndrome) in Japan; mpox in Malawi, Ghana, and Côte d'Ivoire; cholera in India, Kenya, Nigeria, Angola, Sudan, the Democratic Republic of the Congo, and South Sudan; chikungunya fever in the United States and India; poliomyelitis in India, Angola, Laos, Nigeria, and Papua New Guinea; West Nile virus disease in Italy.