Weathering the Storm of High Pathogenicity Avian Influenza in Waterbirds

Abstract. The ongoing panzootic of bird flu caused by high pathogenicity avian influenza (HPAI) virus is unprecedented in scale, with mass mortality events causing population level effects for several waterbird species. While the panzootic commenced in 2021, a number of key events have occurred over the past decades leading to the emergence of this viral lineage. Since 2021, tens of thousands of outbreaks have occurred affecting at least 320 species belonging to 21 orders, of which the vast majority are waterbirds. In this report we provide examples from across the globe associated with population level declines. Only Australia and Antarctica are unaffected, although this could change rapidly. Despite the carnage caused by mass mortality events, there are strategies to better protect waterbirds in both the short and long term. These include prevention of further spillover events from poultry, designing improved surveillance systems to both inform virus epidemiology and to benefit of all wild birds rather than only poultry (and humans), and respond appropriately to outbreaks in wildlife with necessary detail and resources. The loss of waterbirds at the current scale will not only be a conservation disaster, but also an ecological disaster, and therefore response to outbreaks in waterbirds must be prioritized.