The Hong Kong Center for Health Protection announced on January 17^th that a 59-year-old woman from the Sichuan Province of China was hospitalized with H5N6 strain avian influenza.  As with previous cases, there is a history of having visited a live poultry market shortly before onset of symptoms.  This is the 8^th H5N6 case of 2023 and the 89^th in the PRC since the infection was first diagnosed in 2014.

According to the WHO, a total of 90 laboratory-confirmed cases of H5N6 have been diagnosed with 35 fatalities since 2014.

Whole genome sequencing has confirmed that HPAI viruses isolated from human cases belong to the HA clade 2.3.4.4b.  Sequencing of the virus from 11 cases confirmed avian virus lineage.  Amino acid sequences were associated with adaptation in two of the viruses involving PB2 genes and one with an HA1 substitution associated with binding to human cell-receptors.  Since the molecular markers have not been identified in poultry-derived viruses, the substitutions occurred sporadically following infection of the individual human cases.