Influenza in China: Alarming Emergence of a New H6N2 Reassorted Avian Virus

A study reports the identification and characterization of a new reassortant H6N2 virus isolated from poultry in eastern China.   In December 2025, 362 samples were collected from live poultry sold at markets in eastern China. Eight isolates of the H6N2 avian influenza virus were isolated and identified in the sampled chickens. Comprehensive phylogenetic analyses were conducted to better understand the genetic structure and reassortment patterns of this new H6N2 variant. Genetic analyses revealed that this virus possesses a hemagglutinin (HA) gene derived from H6N6 viruses circulating in waterfowl, a neuraminidase (NA) gene derived from the H9N2 virus with endemicity in poultry, and, most notably, six internal genes derived exclusively from the H9N2 lineage—a genetic configuration known to promote interspecies infections and pathogenicity in mammals. This is the first natural detection of an H6N2 virus possessing a constellation of internal gene segments consisting of a gene cassette derived exclusively from H9N2. This virus is already circulating widely among poultry populations in eastern China (Jiangsu, Shandong, and Zhejiang provinces), indicating successful establishment. The emergence of this new H6N2 virus underscores the persistent and evolving threat posed by the co-circulation of multiple avian influenza virus subtypes in China. Given that its molecular genetic profile indicates a high potential for interspecies transmission, the authors recommend the immediate implementation of enhanced and targeted surveillance, as well as control measures in poultry and wild birds, to contain viral spread before human infections occur. Widespread globally among wild birds, avian influenza viruses of the H6Ny subtype have a limited direct impact on animal health but play an important role in genetic transmission within natural reservoirs, promoting reassortment and increasing the diversity of influenza viruses. H6Ny viruses can engage in cross-species transmission and infect mammals, including humans, as confirmed by a human case of H6N1 influenza in Taiwan in 2013 and a human-derived H6N6 strain in Vietnam in 2023. Thus, the circulation and reassortment of H6Ny viruses are likely to generate strains adapted to mammals. The question is not whether this will happen, but when and under what conditions…