15.12.2023

Between September 2 and December 1, 2023, there were documented outbreaks of highly pathogenic avian influenza (HPAI) A(H5) in domestic (88) and wild (175) birds across 23 European countries. Notably, the increase in HPAI virus detections in waterfowl was delayed compared to previous years, potentially linked to a later onset of autumn migration for various wild bird species. The reporting period highlighted common cranes as the most frequently affected species, experiencing mortality events in several European countries, notably Hungary, Italy, and Spain; Between 20,000 and 30,000 cranes have died in Hungary.
Of the eleven genotypes of HPAI virus identified in Europe, seven were newly identified.
On the mammalian front, a serological survey of all fur farms in Finland uncovered 29 additional serologically positive farms during this reporting period. Wild mammals primarily faced challenges in the Americas, with a noteworthy extension of the virus into wild birds and mammals in the Antarctic region being reported for the first time.
As of December 1, 2023, Cambodia reported three fatal and one severe human A(H5N1) infection with clade 2.3.2.1c viruses, while China reported one A(H9N2) infection. No human infections related to avian influenza detections in Finnish fur farms were reported, emphasizing that human infections with avian influenza remain a rare occurrence.