According to recent ProMED releases, Japan has experienced ten outbreaks of highly pathogenic avian influenza, strain H5N1 in eight Prefectures during November to date.  Cases included: -

• 800,000 laying hens in Niigata Prefecture, 337,000 laying hens in Niigata Prefecture.
• 1,050,000 (presumably laying hens) in Kagawa Prefecture.
• 169,000 birds, (presumably laying hens) in Kagawa Prefecture.
• 21,000 birds (unspecified) in Miyagi Prefecture.
• 120,000 birds (presumably laying hens) in Kagoshima Prefecture located on the southern tip of Kyushu. In this case there are 89 commercial poultry units within a six- mile radius of the index farm

In all cases, the strain responsible was characterized as H5N1 and affected farms were depopulated with appropriate surveillance within a six-mile radius of the affected farms.

Outbreaks in Japan representing the commencement of the fall season were preceded by isolation of H5N1 virus from migratory and domestic free-living birds. If cases continue with the November incidence rate losses could attain the extent of the 2022 epornitic requiring importation of shell eggs and liquid.