The December 24th edition of EGG-NEWS, documented an outbreak of H5N1 highly pathogenic avian influenza (HPAI) near St. Johns on the Avalon Peninsula of the Province of Newfoundland and Labrador. The affected flock comprised 409 mixed species including geese, ducks, bantams, and turkeys held for exhibition. Subsequent to the outbreak, genome sequencing was performed on nine identical isolates that determined that all eight gene segments were of Eurasian origin. The virus was characterized as an H5N1 strain of the clade 2.3.4.4 b, related to the goose/guangdong G1/96-lineage This virus is currently circulating in wild birds and poultry in Europe and is the first identification of this clade in the Americas. An H5N1 virus was last identified in North America during 2014 and was ultimately responsible for the epornitic of 2015. This virus was introduced from Asia across the Bering Strait, initially affecting poultry in the Frasier Valley of British Columbia and then appearing during December in northern California.
The virus in the latest outbreak in Canada is however distinct from the 2014 introduction into British Columbia and California. It is evident that wild bird movement was responsible for transatlantic carriage possibly through serial contact among diverse species moving westward through Iceland and Greenland. The fact that there are few commercial and backyard domestic flocks in the northern Maritime provinces suggests that the virus may be widespread in migratory birds but unrecognized without appropriate surveys which have been initiated.
The introduction of an Eurasian strain of HPAI, responsible for outbreaks in Europe is cause for concern and should result in intensified biosecurity in more the populated Maritime provinces and the entire Northeastern seaboard of the U.S.