Objective To summarize and analyze the epidemiological characteristics and field investigation of the first case of human infection with avian influenza A(H10N3) virus in northern China and to provide reference for the investigation and management of human infection with animal-derived influenza in the future.
Methods Case epidemiological investigation, identification and medical observation of co-exposed people and close contacts, and tracing investigation and analysis of infection source were carried out. Samples were collected from the case, co-exposed persons, close contacts, poultry, and the external environment. Real-time fluorescent quantitative RT-PCR was used to detect influenza A virus. The positive samples were subjected to metagenomic sequencing and compared.
Results This is the first case of human infection with the avian influenza A(H10N3) virus in northern China, and a third-party laboratory performed the detection. The patient became ill on April 13, 2025, with no history of contact with similar cases prior to symptom onset but with a history of exposure to poultry. The macrogene test of bronchoalveolar lavage fluid was positive for avian influenza A(H10N3) virus on April 28, 2025. A total of 168 samples were collected from co-exposed individuals, close contacts, poultry, and the external environment, and all were negative for avian influenza A(H10N3) virus. Metagenomic sequencing analysis showed that the sequence had high homology with the human infection case of avian influenza A(H10N3) virus reported in Guangxi Zhuang Autonomous Region in December 2024. After taking emergency measures such as medical observation of close contacts, harmless treatment of poultry in the sick home, and disinfection of suspected exposure places, no secondary cases occurred. The case was cured and discharged on May 14.
Conclusions The source of the first human case of avian influenza A(H10N3) infection in northern China remains unclear, but no human-to-human transmission has been found. It is important to improve the sensitivity of surveillance for new subtypes of animal-derived influenza viruses, such as avian influenza A(H10N3), and to strengthen joint prevention and control between health and animal husbandry departments to support scientific approaches to preventing and controlling human infection with these viruses.

China: Eight human cases of avian influenza A(H9N2) reported Chongqing Municipality, Guizhou, Hunan, Yunnan Provinces. One human case of avian influenza A(H10N3) reported in Shaanxi Province

Fulltext of case report in Chinese: http://www.flu.org.cn/scn/article-25419.html