Characterization of a novel reassortant H7N3 highly pathogenic avian influenza virus isolated from a poultry meat product taken on a passenger flight to Japan.

A new reassortant H7N3 avian influenza virus (AIV) was isolated from a duck meat product that was illegally taken on board a passenger flight from China to Japan in March 2018. Sequencing analysis revealed that the H7N3 isolate, A/duck/Japan/AQ-HE30-1/2018 (Dk/HE30-1) (H7N3), was a reassortant highly pathogenic avian influenza virus (HPAIV) that contained the haemagglutinin (HA) gene of Chinese H7N9 HPAIV. Dk/HE30-1 (H7N3) possessed a novel polybasic sequence motif PEVPKRRRTAR/GLF at the HA cleavage site that has never previously been reported in H7 HPAIVs. The HA antigenicity of Dk/HE30-1 (H7N3) slightly differed from that of H7N9 HPAIVs previously reported. These findings will help further our knowledge of the circulation and genetic evolution of emerging AIVs in endemic areas.