Objective To detect global infectious disease events occurring outside China in March 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 March 2025, 14 infectious diseases were detected to form events or outbreaks in 37 countries worldwide. In terms of importation risk to China, there are 15 medium-risk events; in terms of international travel risk, there are 17 high-risk events and 26 medium-risk events.

Conclusion It is recommended to pay general attention to diphtheria in South Africa, pertussis in the United States, dengue fever in Russia, Philippines, the United States, Indonesia, and Bangladesh, mpox and poliomyelitis in Pakistan, cholera in Ethiopia and Myanmar, chikungunya in Brazil, Germany, France, and India, and measles in the United States and Vietnam, which may pose import risks. In terms of overseas travel risks, it is recommended that international travelers pay close attention to the diphtheria in South Africa and Nigeria; dengue fever in Paraguay, Brazil, Philippines, Uruguay, Peru, Bangladesh, Mexico, Tonga, India, and Indonesia; and cholera in Mozambique, Zimbabwe, South Sudan, Angola, and Haiti. Compared to February 2025, general attention should be paid to Ebola virus disease in Uganda, dengue fever in Argentina, monkeypox in Tanzania, Zambia, and Pakistan, yellow fever in Peru, chikungunya in Brazil, France, and India, poliomyelitis in Pakistan, Djibouti, Chad, and Nigeria, and measles in Morocco, Yemen, Angola, Argentina, Brazil, Mongolia, Kyrgyzstan, Mexico, and Vietnam in March 2025.