ETIDIOH - NEW

  Abstract Biodiversity loss is one of the greatest challenges facing Earth today. The most direct information on species losses comes from recent extinctions . However, our understanding of these recent, human-related extinctions is incomplete across life, especially their causes and their rates and patterns among clades, across habitats and over time. Furthermore, prominent studies have extrapolated from these extinctions to suggest a current mass extinction event . Such extrapolations assume that recent extinctions predict current extinction risk and are homogeneous among groups, over time and among environments. Here, we analyse rates and patterns of recent extinctions (last 500 years). Surprisingly, past extinctions did not strongly predict current risk among groups. Extinctions varied strongly among groups , and were most frequent among molluscs and some tetrapods , and relatively rare in plants and arthropods . Extinction rates have increased over the last five centuries , b...

  Abstract Mosquito-borne diseases are deeply embedded within ecological communities, with environmental changes—particularly climate change—shaping their dynamics . Increasingly intense droughts across the globe have profound implications for the transmission of these diseases , as drought conditions can alter mosquito breeding habitats , host-seeking behaviours and mosquito–host contact rates . To quantify the effect of drought on disease transmission, we use West Nile virus as a model system and leverage a robust mosquito and virus dataset consisting of over 500 000 trap nights collected from 2010 to 2023, spanning a historic drought period followed by atmospheric rivers. We pair this surveillance dataset with a novel modelling approach that incorporates monthly changes in bird host community competence , along with drought conditions , to estimate the effect of drought severity on West Nile virus risk using panel regression models. Our results show that while drought decreases ...

  Significance Highly pathogenic avian influenza virus (HPAIV) threatens wildlife, agriculture, and humans. Along the East Asian–Australasian Flyway , a major waterfowl migration corridor and HPAIV hot spot, landscape changes are altering migratory bird distributions and increasing opportunities for wild–poultry interactions . By integrating empirical data into an individual-based model, we show that landscape change between 2000 and 2015 reshaped waterfowl migration , substantially increased wild-poultry spillover , and avian influenza virus (AIV) reassortment in poultry , our proxy for potential AIV diversification and emergence of novel subtypes. Risk regions expanded across southeastern China, the Yellow River basin, and northeastern China . These findings highlight the importance of landscape changes in potentially elevating AIV diversification and emergence, and the landscape dynamics should be integrated into future studies. Abstract Highly pathogenic avian influenza viruses...

Abstract Highly pathogenic avian influenza (HPAI) has become a critical threat to wildlife, shifting from a seasonal epizootic to a persistent, year-round panzootic with global consequences . Here, we summarize the origin, evolutionary mechanisms, and expanding host range of the current H5N1 virus (clade 2.3.4.4b) and assess its impact on wildlife . Over the past five years, HPAI has caused the deaths of millions of wild birds , causing dramatic population declines in several seabird species . However, comprehensive quantitative mortality data remain scarce, as existing records are often anecdotal, focus on localized mass die-offs, and thus represent only a fraction of the true magnitude of mortality. This gap in data limits the ability to predict outbreak dynamics and mitigate long-term consequences. Using the Northwestern European Sandwich Tern (Thalasseus sandvicensis) population as a case study, we demonstrate the value of integrating mortality data with ecological, serological and...

Abstract The ongoing panzootic of H5N1 high pathogenicity avian influenza virus (HPAIV) has caused the deaths of over half a billion wild birds and poultry , and has led to spillover events in both wild and domestic mammals , alongside sporadic human infections . A key driver of this panzootic is the apparent high viral fitness across diverse avian species, which facilitates an increased interface between wild and domestic species. Columbiformes (pigeons and doves) are commonly found on poultry premises and are highly connected to humans in urban settlements, yet relatively little is known about their potential role in contemporary HPAIV disease ecology. Here we investigated the epidemiological role of pigeons (Columba livia) by determining their susceptibility using decreasing doses of clade 2.3.4.4b H5N1 HPAIV (genotype AB). We investigated infection outcomes and transmission potential between pigeons and to chickens for each dose. Following direct inoculation, pigeons did not develo...

Abstract Highly pathogenic avian influenza (HPAI) represents a threat to animal and human health , with the ongoing H5N1 outbreak within the H5 2.3.4.4b clade being the largest on record. However, it remains unclear what factors have contributed to its intercontinental spread . We use Bayesian additive regression trees, a machine learning method designed for probabilistic modelling of complex nonlinear phenomena, to construct species distribution models (SDMs) for HPAI clade 2.3.4.4b presence. We identify factors driving geospatial patterns of infection and project risk distributions across Europe . Our models are time-stratified to capture both seasonal changes in risk and shifts in epidemiology associated with the succession of H5N6/H5N8 by H5N1 within the clade . While previous studies aimed to model HPAI presence from physical geography, we explicitly consider wild bird ecology by including estimates of bird species richness, abundance of specific taxa, and "abundance indices...

Abstract H5Nx clade 2.3.4.4b high-pathogenicity avian influenza viruses (HPAIVs) have decimated wild bird and poultry populations globally since the autumn of 2020. In the United Kingdom (UK) and in continental Europe , the H5N8 subtype predominated during the first epizootic wave of 2020/21, with few detections of H5N1 . However, during the second (2021/22) and third (2022/23) epizootic waves , H5N1 was the dominant subtype. The rapid shift in dominance from H5N8 to H5N1 was likely driven by a combination of virological, immunological, and/or host-related factors . In this study, we compared viral fitness and immunological responses in ducks , a key reservoir species, using dominant genotypes of H5N1 (genotype AB) and H5N8 (genotype A) from the second wave. While viral shedding dynamics were similar for both viruses, H5N8 was more pathogenic . Antigenic analysis of post-infection duck sera revealed that the haemagglutinin (HA) protein was antigenically similar across clade 2.3.4.4b H5...

Abstract The avian influenza virus (AIV) primarily affects birds and poses an increasing concern due to its growing adaptability to other hosts , heightening zoonotic risks . The adaptability is a key factor in AIV to infect multiple non-avian species, including humans , companion animals , aquatic mammals , carnivores , and other mammals. The virus is evolving through genetic mutations and reassortments , leading to the emergence of AIV strains with enhanced virulence and adaptability in mammals. This highlights the critical need to understand the genetic factors of AIV, including mutations in polymerase proteins , surface antigens , and other regulatory proteins, as well as the dynamics of AIV- host interactions and environmental factors such as temperature, humidity, water salinity, and pH that govern the cross-species adaptability of the virus. This review provides comprehensive insights into the molecular/genetic changes AIV undergoes to adapt in mammalian hosts including bovines,...

Abstract Pigeons (Columba livia) are usually kept as free-ranging or racing birds, and they have direct contact with livestock, poultry, and humans . Therefore, they may have an important role in the ecology of influenza virus among various species. In the present study, we bring together all available sequence data of pigeon avian influenza virus (AIV) from public databases to address the current understanding of the genomic characteristics and emergence of each subtype of AIV in pigeons. Collectively, we identified 658 pigeon AIV strains in 21 countries across the world, which were mainly distributed in Europe, Asia, and North America. H1 (2), H2 (1), H3 (8), H5 (71), H6 (16), H7 (16), H9 (543), and H11 (1) AIV subtypes have been identified in pigeons. In addition, we interrogate features of the H5, H6, H7, and H9 subtypes of pigeon AIV, which are relatively common in pigeons. It is particularly noteworthy that the H5 AIV strains identified in pigeons are all classified as HPAIV. For...