#18,900
The above map, showing reported outbreaks or spillovers of HPAI viruses around the world since October of 2024, illustrates how much of the world simply isn't looking for, or willing (or able) to report, avian flu.
Vast areas of Canada, South America, Africa, and Eurasia are shown blank, although there is little doubt that avian flu is circulating in those regions (the exception being Oceania, where the virus has not been detected . . . yet).
Many of these regions are remote or sparsely populated, some are in countries with suboptimal surveillance and testing capabilities, and a few represent nations that - for economic or political reasons - have no desire to share the data.
But even here in the United States, surveillance is largely passive - and while the USDA's wild HPAI bird dashboard shows > 15,000 detections in wild birds - in large die offs (100s or 1000s of birds), only a small number may be tested and reported.
Spillovers into mammals - once relatively rare - have become both commonplace and constant as well; many exhibiting devastating neurological manifestations.The actually toll on wild birds is incalculable, but likely runs into the hundreds or millions, perhaps billions.
While concerns over a potential pandemic threat to humans are understandable, this virus is already a deadly epizootic in hundreds of avian and mammalian species. And its host range continues to expand (see ISIRV: Update on H5N1 Panzootic: Infected Mammal Species Increase by Almost 50% in Just Over a Year).
Previously, we've looked at concerning reports of endangered avian species being ravaged by the inexorable spread of HPAI (see USFWS Update: 21 Condor Deaths Attributed To HPAI H5 and EID Journal: HPAI A(H5N1) Outbreak in Endangered Cranes, Izumi Plain, Japan, 2022–23).
letter| October 06 2025Abstract
Highly Pathogenic Avian Influenza (HPAI) Detected in 41 Species at Risk in Canada
Damien O. Joly Corresponding Author; Yohannes Berhane; Jeff Bowman; Jolene A. Giacinti; Dayna Goldsmith; Nathan Hentze; Megan E.B. Jones; Claire M. Jardine; Stéphane Lair; Erin K. Leonard; Ariane Massé; Samira Mubareka; Cynthia Pekarik; Julie Paré; Neil Pople; Margo J. Pybus; Brian Stevens; Trevor Thompson; Amie Enns; Maeve Winchester
J Wildl Dis (2025) https://doi.org/10.7589/JWD-D-25-00048
Highly pathogenic avian influenza (HPAI) H5Nx virus clade 2.3.4.4b has impacted wild birds and mammals in Canada since late 2021, including species at risk. We compared detections and conservation status to highlight the need to integrate disease surveillance with conservation planning when assessing risks and to guide management.
(SNIP)
During the period November 2021 to November 2024, HPAI H5Nx was detected in at least 1 individual of 41 SAR across all 10 Canadian provinces, including 20 species on the Red List as Endangered or Threatened (Table 1). No SAR were found with HPAI in the three Canadian Territories (Northwest Territories, Nunavut and Yukon). All 41 species were birds from the following Orders: Accipitriformes (9 species), Anseriformes (11 species), Cathartiformes (1 species), Charadriiformes (8 species), Falconiformes (2 species), Passeriformes (1 species), Pelecaniformes (2 species), Podicipediformes (2 species), Strigiformes (4 species), and Suliformes (1 species), and represented 41% of all species detected with HPAI in this period (n¼100) and 44% of bird species (n¼93).
Although HPAI was detected in eight mammal species, none of these species met the criteria for SAR.Four of the bird species in which HPAI was detected were also assessed as at risk nationally by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC): Barn Owl (Tyto furcata), Horned Grebe (Podiceps auritus), Snowy Owl (Bubo scandiacus), and Western Grebe (Aechmophorus occidentalis).
This study highlights HPAI as a potential additional conservation threat to species already at risk.However, there are several limitations to this study. First, HPAI surveillance relies on reporting to wildlife authorities, so suffers from the usual limitations of scanning surveillance programs (e.g., Giacinti et al. 2023) and probably underestimates the number of individuals and species affected by HPAI.
Specifically, smaller and/or more cryptic species are probably underrepresented, as well as those with habitats away from human occupation.
Furthermore, although an informal review of available Canadian Wildlife Health Cooperative data indicated that a majority of HPAI-positive birds had clinical signs indicative of HPAI-associated mortality, detection of HPAI in an individual does not necessarily mean that the individual died of HPAI; more research is necessary to determine species specific vulnerability to HPAI
A little over 2 years ago, in Avian Flu's New Normal: When the Extraordinary Becomes Ordinary, I wrote about the numbing effect that comes with the constant barrage of HPAI H5 reports from around the world.
Events that were nearly unthinkable two or three years ago (e.g. Repeated trans-Atlantic introduction of avian flu from Europe, the spread of HPAI H5 across the length of South America, numerous spillovers of H5 into mammalian species, and the arrival of HPAI H5 to Antarctica) have now become `the new normal'.
While we may have become inured to these happenings, that doesn't make them any less impactful to our shared global ecosystem. What future challenges may arise from these continued viral insults to non-human species is difficult to predict.
But given our largely passive response to avian flu, we appear on track to find out.
