Background: Since the first human case of H10N3 Avian Influenza in Jiangsu, China (April 2021), three cases have been reported globally. However, clinical and treatment data remain limited. Therefore, we describe the fourth patient´s epidemiology, clinical manifestations, diagnostics, treatment.

Case presentation: A 23-year-old woman, previously well, presented on 12 Dec 2024 with fever, dry cough and breathlessness after pig and chicken contact. CT showed bilateral pneumonia. Despite high-flow oxygen and broad-spectrum antibiotics she deteriorated, requiring intubation, lung-protective ventilation and VV-ECMO. Bronchoalveolar lavage isolated H10N3 influenza virus. Treatment with oseltamivir and baloxavir plus prone-position ventilation led to clinical improvement.

Conclusion: Due to its nonspecific early symptoms, H10N3 is difficult to diagnose promptly, increasing the risk. Early recognition, antiviral therapy, and aggressive support are essential in managing severe infections.