The Statens Serum Institute in Denmark (equivalent to the CDC) has reported on isolation of avian influenza virus, strain H5N8, presumably responsible for mortality in harbor seals (Phoca vitulina).  Concurrently with the cases diagnosed on September 21st 2021, HPAI was prevalent in poultry flocks with 16 cases reported on commercial farms and 300 wild bird isolates were identified during the migratory season.  During the current late Winter period infection with HPAI H5 Clade 2.3.4.4b is prevalent in migratory waterfowl and other bird species and is responsible for mortality in poultry flocks.

Veterinary laboratories in northern Europe have identified H5 avian influenza in wild foxes demonstrating neurologic signs and in farmed mink with involvement of the respiratory tract.  Infection of mammals represents the potential for mutation with the possibility of infection of humans.