Biology subjects

Seyer, Y.

Publications and source records attributed to Seyer, Y..

3 recordsLinked to original sources

bioRxiv2025

IRIS PIGMENTATION IRREGULARITIES FOLLOWING AN AVIAN INFLUENZA OUTBREAK: IMPLICATIONS FOR DISEASE SURVEILLANCE AND POPULATION MONITORING IN A COLONIAL SEABIRD

Emerging infectious diseases can have catastrophic impacts on wildlife populations, yet identifying individuals that survived exposure, especially when external symptoms are absent, remains challenging. Since 2021, a virulent strain of highly pathogenic avian influenza virus (HPAIV H5N1 clade 2.3.4.4b) has caused unprecedented mortality in wild birds across continents. Northern Gannets (Morus bassanus) are among the species that suffered significant population declines in Europe and North America. At North Americas largest gannet colony (Bonaventure Island) dramatic mortality and reproductive failure occurred in 2022. Following this event, researchers noted a subset of gannets displaying irregular iris pigmentation, raising the possibility that this visible change may indicate a lasting effect of infection. Here, we build on earlier observations linking irregular iris pigmentation to HPAIV exposure in gannets using anti-nucleoprotein (NP) and anti-hemagglutinin (H5) antibodies. This provides the first quantitative test of this relationship using serological data and field-based digital photography. Iris irregularities were strongly associated ({rho} = -0.72) with antibodies to NP, supporting the hypothesis that they can indicate past exposure. The likelihood of NP antibody detection increased with iris pigment irregularity--about 50% likelihood at 40% irregularity, 65% at 50%, 77% at 60%, and over 90% above 77% irregularity. Moderate correlations ({rho} = 0.30) were observed for H5 antibodies. Our findings provide quantitative support for the hypothesis that iris pigmentation irregularities may serve as a visible, non-invasive marker of past HPAIV exposure in gannets. If validated across colonies and years, iris assessment could offer a rapid tool for tracking population health and recovery following HPAIV outbreaks, enhancing conservation monitoring and disease surveillance. Lay SummaryOur research shows clear evidence that irregular iris pigmentation in Northern Gannets is strongly linked to past infection with a deadly bird flu strain. This visible marker could allow scientists to rapidly identify surviving birds and monitor population health after outbreaks, helping conservation efforts across affected colonies. HighlightsO_LIIris pigmentation irregularities reveal past avian influenza exposure. C_LIO_LIExtent of iris pigmentation irregularity correlates with antibody levels. C_LIO_LIExposure likelihood increases with degree of iris pigmentation irregularity. C_LIO_LICould provide a rapid, non-invasive tool for wildlife disease and conservation monitoring. C_LI Graphical abstracts O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=134 SRC="FIGDIR/small/685885v1_ufig1.gif" ALT="Figure 1"> View larger version (60K): org.highwire.dtl.DTLVardef@12fa683org.highwire.dtl.DTLVardef@15d23b1org.highwire.dtl.DTLVardef@1d2425eorg.highwire.dtl.DTLVardef@10367cd_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗

bioRxiv2024

Seabird and sea duck mortalities were lower during the second breeding season in eastern Canada following the introduction of Highly Pathogenic Avian Influenza A H5Nx viruses

H5N1 clade 2.3.4.4b viruses have caused significant mortality events in various wild bird species across Europe, North America, South America, and Africa. In North America, the largest impacts on wild birds have been in eastern Canada, where over 40,391 wild birds were reported to have died from highly pathogenic avian influenza (HPAI) between April and September 2022. In the year following, we applied previously established methods to quantify total reported mortality in eastern Canada for a full year October 2022, to September 2023. In this study, we (i) document the spatial, temporal and taxonomic patterns of wild bird mortality in the 12 months that followed the mass mortality event in the summer of 2022 and (ii) quantify the observed differences in mortality across the breeding season (April to September) of 2022 and 2023. In eastern Canada, there was high uncertainty about whether 2023 would bring another year of devastating HPAI-linked mortalities. Mortalities in the breeding season were 93% lower in 2023 compared to 2022 but encompassed a more taxonomically diverse array of species. We found that mortalities in the fall and winter (non-breeding season) were dominated by waterfowl, while mortalities during the spring and summer (breeding season) were dominated by seabirds. Due to a low prevalence of HPAI among the subset of tested birds, we refrained from broadly attributing reported mortalities in 2023 to HPAI. However, our analysis did identify three notable mortality events linked to HPAI, involving at least 1,646 Greater Snow Geese, 232 Canada Geese, and 212 Northern Gannets. This study emphasizes the ongoing need for H5NX surveillance and mortality assessments as the patterns of mortality in wild populations continue to change.

ecology↗

bioRxiv2024

Wild bird mass mortalities in eastern Canada associated with the Highly Pathogenic Avian Influenza A(H5N1) virus, 2022

In 2022, a severe outbreak of clade 2.3.4.4b Highly Pathogenic Avian Influenza (HPAI) H5N1 virus resulted in unprecedented mortality among wild birds in eastern Canada. Tens of thousands of birds were reported sick or dead, prompting a comprehensive assessment of mortality spanning the breeding season between April 1 and September 30, 2022. Mortality reports were collated from federal, Indigenous, provincial, and municipal agencies, the Canadian Wildlife Health Cooperative, non-governmental organizations, universities, and citizen science platforms. A scenario analysis was conducted to refine mortality estimates, accounting for potential double counts from multiple sources under a range of spatial and temporal overlap. Correcting for double counting, an estimated 40,966 wild birds were reported sick or dead in eastern Canada during the spring and summer of 2022. Seabirds and sea ducks, long-lived species that are slow to recover from perturbations, accounted for 98.7% of reported mortalities. Mortalities were greatest among Northern Gannets (Morus bassanus; 26,193), Common Murres (Uria aalge; 8,133), and American Common Eiders (Somateria mollissima dresseri; 1,945), however, these figures underestimate total mortality as they exclude unreported deaths on land and at sea. In addition to presenting mortality estimates, we compare mortalities with known population sizes and trends and make an initial assessment of whether population-level impacts are possible for the Northern Gannet, a species that has suffered significant global mortality, and two harvested species, Common Murre and American Common Eider, to support management decisions. We hypothesize that population-level impacts in eastern Canada are possible for Northern Gannets and American Common Eiders but are unlikely for Common Murres. This study underscores the urgent need for further research to understand the broader ecological ramifications of the HPAI outbreak on wild bird populations.

zoology↗