Genesis, Evolution and Host Species Distribution of influenza A (H10N3) Virus in China

A recent article by Wang in the Journal of Infection ( 1 ) confirmed the first case of human infection with H10N3 avian influenza virus (AIV) in Zhenjiang, Jiangsu Province, China, in April 2021. Transmission of H10 subtype AIVs from birds to humans is uncommon but has occurred in history. The first reported human infections with an H10 subtype influenza virus occurred in Egypt in 2004 ( 2 ). In subsequent surveillance, cross-species transmission of subtype H10 influenza virus has been detected occasionally. The most important of these events were three patients infected with the H10N8 subtype influenza virus and two died in China in 2013 ( 3 ). Wang also analyzed the whole genome of the first human-origin H10N3 isolate, indicating that this virus is an avian-origin reassortant strain with the hemagglutinin (HA) and neuraminidase (NA) genes from H10N3 viruses and six internal genes from H9N2 viruses ( 1 ). WHO considered this human case was a sporadic transmission of H10 from avian hosts to humans. However, up to now, there were no same genotype avian-origin H10N3 viruses having been reported.