Avian influenza virus strain H5N5 expressing Eurasian genes has been isolated from wild birds in Europe since late 2020.  Five neuraminidase subtypes of H5 have been recovered from avian species including N1, N3, N4, N5 and N8 all belonging to clade 2.3.4.4b. The incident cases in Europe were from marine birds and some captive poultry.  The impact of H5Nx viruses is well documented although recently overshadowed by the panornitic of H5N1, Highly Pathogenic Avian Influenza.

Recent reports from Canada have confirmed H5N5 in marine birds presumably following the same migratory pattern across the northern Atlantic as occurred with H5N1 during 2021.  The presence of H5N5 was first detected in January 2023.  Of concern are recent reports of raccoons dying of H5N5 avian influenza, presumably contracted from scavenging dead birds.

It is questioned whether the emergence of H5N5 presages an epornitic or whether the identification of this subtype of H5 virus is a reflection of increased surveillance and intensity of laboratory serotyping.

Mortality in raccoons was recorded near Charlottetown, the capital of Prince Edward Island. The current disease situation in mammals and free-living birds is subject to surveillance by Canadian animal health authorities with reference to the World Organization for Animal Health.

The USDA-APHIS has reported 191 confirmed isolations of H5N1 from mammals in eight states with all affected species known to consume dead birds.  Surveillance will obviously be intensified in the Maritime Provinces of Canada and along the Atlantic Flyway extending over northeastern U. S. states. The prevalence in migratory birds during the fall and the pathogenicity of the virus to domestic poultry will be ascertained in order to plan for any required programs of prevention and control.