Epidemiological and Genetic Characteristics of the H3 Subtype Avian Influenza Viruses in China

Avian influenza viruses(AIVs)are naturally preserved in waterfowls and sometimes spill over to infect humans and mammalian animals.The H3 subtype is one of the most prevalent influenza virus subtypes in waterfowls.Since 2000,H3 subtype AIVs have been continuously isolated from poultry and wild birds in the mainland of China,which implied a dynamic spread in large-scale geography and multiple species.Combinations of H3 with N1–N8 subtypes were reported,among which H3N2 and H3N8 subtypes predominated.