A case of human infection by H3N8 influenza virus

Here, we report a human case of infection with a novel, reassorted avian influenza A virus, H3N8. The patient was a 5-year-old child with no significant medical history who developed fever and cough on May 9, 2022. On May 10, he was admitted to the hospital into the fever department of the First Hospital of Changsha, presenting with a fever of 40°C, chills, sore throat, fatigue, and a runny nose. A swab was collected on the same day of admission, and a novel coronavirus nucleic acid test returned a negative result. After two days of self-medication, his condition and respiratory symptoms improved significantly. However, on May 13, the swab that was collected on May 10 was found to be positive for influenza A N8 by real-time PCR (RT–PCR) through routine influenza surveillance. On May 15, the RT–PCR re-examination tested positive for influenza A N8 again, and the influenza A (H3N8) full genome sequence was obtained from the initial swab collected on May 10.