A case of H10N3 avian influenza in a young woman.

Background: Avian influenza viruses, frequently identified in wild waterfowl and poultry, have occasionally been transmitted to humans, causing severe respiratory diseases. This report covers the fourth case of a human contracting the H10N3 subtype of avian influenza virus.

Methods: A case of novel avian influenza virus subtype H10N3 was detected in a female patient hospitalized in Nanning, China, in December 2024. Blood, feces, urine, and bronchoalveolar lavage fluid were collected from the patient for medical analysis during the hospitalization.

Findings: A case of novel avian influenza virus subtype H10N3 was detected in a female patient hospitalized in Nanning, China, in December 2024. She also had a history of exposure to live poultry. This case represents the fourth documented instance of H10N3 infection in humans. She was treated with a combination of baloxavir marboxil and oseltamivir. She exhibited extensive lung lesions. Additionally, she presented complicating factors, including secondary infection, pneumothorax, and numbness in her feet. She recovered and was discharged on March 27, 2025, amid comprehensive supportive care, which included therapy with baloxavir marboxil, oseltamivir, fluconazole, tigecycline, amikacin, extracorporeal membrane oxygenation, and rehabilitation therapy.

Conclusions: The virus was effectively cleared by the combination therapies. The internal genes of the H10N3 virus in this patient were highly homologous to the corresponding genes from the A/Yunnan/2024 virus (GenBank accession numbers, hemagglutinin [HA] [GenBank: PP555669] and PB-2 [GenBank: PP555666]).

Funding: This work was funded by the Fourth People's Hospital of Nanning - Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome (HIV/AIDS) Clinical Treatment Center of Guangxi (Nanning).