In March 2024 and April 2025, Dongxing customs under Nanning customs carried out infectious disease monitoring according to the regulations at Dongxing port, and two Vietnamese border residents were found to have positive influenza a nucleic acid test results after rapid detection at the port. Nanning customs carried out risk assessment according to the situation of human infection with H5N1 avian influenza in surrounding countries. The positive samples were sent to the laboratory of Guangxi International Travel Health Care Center for further testing. The virus typing test results confirmed that human infection with H5N1 avian influenza nucleic acid was positive. The above two cases were detected for the first time in China in 2024 and 2025.

After receiving the notification of the test results, as the positive cases have returned to Vietnam, Nanning customs immediately launched the Sino Vietnam "two countries and four parties" border health and quarantine cooperation mechanism, informed the health and quarantine departments of Vietnam´s adjacent ports, and requested to provide case information, carry out remote flow survey and follow-up tracking, and notify the local health and disease control departments of the relevant situation, and do a good job in the follow-up investigation and disposal of local risks.

Nanning customs successfully handled two cases of human infection with H5N1 avian influenza, without causing adverse effects such as the domestic spread of major infectious diseases and the infection of internal staff. This fully reflects the customs´ contribution to strengthening the frontier health quarantine work, preventing the cross-border spread of infectious diseases, and ensuring the safety and health of the public. It is an effective measure for the customs to effectively build a national biosafety barrier, and also a vivid embodiment of the customs´ "guarding the country and promoting development".