Avian Influenza among humans and animals during 2013-2022
A comprehensive review of current global Avian Influenza (AI) virus surveillance data was published by Szablewski et al. in the journal JMIR Public Health and Surveillance.
Between 2013 and 2022, more AI virus outbreaks in animals were reported by WOAH Member Countries than in the previous 8 years, with 26 Member Countries reporting their first animal AI virus outbreak. From January 2013 to June 2022, there were reports of more than 21,000 AI virus outbreaks in animals and 2000 human infections with AI viruses globally. As many as 10 new HPAI virus subtypes (new hemagglutinin/neuraminidase [HA/NA] combinations) were identified in animals, representing an almost 2-fold increase in the number of subtypes identified in the 2013-2022 period compared with the previous 8 years. This likely reflects broadened viral diversity, increased reporting, and enhanced surveillance. Although there were 34 subtypes reported, only 4 accounted for 89.74% (19,068/21,249) of animal outbreaks; all 4 were of the HPAI H5 lineage. During the 2013-2022 period, the predominant subtype causing animal outbreaks changed from H5N1 to H5N8, for all years but 1. However, in 2022, H5N1 reemerged as the predominant subtype. From 2016 to 2022, about 14% of outbreaks each month occurred in a new animal category with wild birds representing the highest percentage (36.9%, 162/439). This finding suggests that in addition to spreading geographically, AI viruses are also moving into more animal categories. Increases in geographic and animal category reporting could be attributed to increased poultry production and commercial trade, increased exposure to wild birds through repeated annual migrations of infected birds, changes in migration patterns because of climate change or land conversion to agricultural production, viral genetic evolution, and improved AI virus awareness and surveillance capacity.
