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ABSTRACT The high-altitude ecosystems of Qinghai Province, China, harbor unique viral communities shaped by extreme environmental conditions and host adaptations. This study presents a comprehensive genetic characterization of the marmot gut virome , revealing novel viral strains with zoonotic potential . Using viral metagenomics, we analyzed intestinal contents from 70 marmots collected from Chengduo and Maqin counties. Sequencing on the Illumina NovaSeq 6000 platform identified 19 viral genomes belonging to four major families : Adenoviridae, Astroviridae, Parvoviridae, and Picornaviridae , along with four novel circular Rep-encoding single-stranded DNA (CRESS DNA) viruses. Phylogenetic analyses demonstrated close relationships between marmot-derived strains and viruses from humans, bats, and other mammals , highlighting potential cross-species transmission risks . Notably, bat-associated adenoviruses showed closer phylogenetic proximity to human strains, while novel parvoviruses for...

Abstract Avian influenza viruses undergo frequent genetic reassortment, which can coincide with phenotypic changes in transmission, pathogenicity, and host species niche . Since 2020, clade 2.3.4.4b H5 high pathogenicity avian influenza viruses (HPAIVs) have driven a global panzootic , causing mass mortality in wild birds, poultry , and, for the first time, repeated spillover infections in a variety of mammalian species . This resurgence of H5 HPAIV has coincided with a dramatic increase in the number of circulating reassortant strains ; however, the scale, impact and drivers of these reassortants remain unknown. Here, we combined statistical and phylodynamic modelling to reconstruct the global evolutionary dynamics of H5Nx viruses across four epizootic seasons (2020-2024). We identified 209 genetically distinct reassortants , stratified into three transmission categories based on their phylogenetic and epidemiological profiles. Accounting for sampling depth and HPAIV incidence, we est...

Abstract Introduction :  In 2023 and 2024, mass mortalities of swans occurred on the Caspian coast of Kazakhstan , which affected more than seven hundred birds of a local population of 10–15 thousand. It is widely known that viral infections significantly affect the microbiome content of various organisms , but the influence of H5N1 infection in the gut microbiota of wild birds remains little studied. Almost no information is available on postmortem microbial changes after the devastating impact of H5N1 influenza. Methods :  In addition to standard routine virological studies , we were interested in investigating the microbiological changes resulting from infection with the highly pathogenic H5N1 using 16S rRNA gene sequencing. Results :  Virological studies of samples taken from the dead swans identified the highly pathogenic influenza virus H5N1 subtype as the primary cause of mortality. 16S analysis of samples from freshly dead swans revealed patterns of microbial dysb...

{Excerpt} To the Editor : The article “Henipavirus in northern short-tailed shrew, Alabama, USA,” (1), describing the discovery of Camp Hill virus (family Paramyxoviridae ) in the northern short-tailed shrew (Blarina brevicauda), sparked major media attention and raised concerns about zoonotic transmission and potential pandemic risk. However, it would be advisable to reevaluate this virus discovery within the broader context of related viruses. The increase in identified henipa-like viruses in various shrew species (2–4) led the International Committee on Taxonomy of Viruses to classify these henipa-like viruses into a distinct genus, Parahenipavirus (5), acknowledging their genetic difference from the highly pathogenic Hendra and Nipah virus. (...) Source: US Centers for Disease Control and Prevention,  https://wwwnc.cdc.gov/eid/article/31/8/25-0401_article ____

Abstract Sampling of mammal communities across the United States during 2022–2023 detected evidence of SARS-CoV-2 antibodies in 3 new species and 2 previously described species and evidence of influenza A antibodies in 2 previously described species . Our analysis provides surveillance and sampling guidance for detection of rare exposure events. Source: US Centers for Disease Control and Prevention,  https://wwwnc.cdc.gov/eid/article/31/8/24-1671_article ____

ABSTRACT In recent years, high pathogenicity avian influenza viruses (HPAIVs) have spread among wild, captive, and domestic birds, as well as mammals . Beyond the resulting economic and ecological losses , spillover into mammals has raised concerns about a potential pandemic . Viral tropism refers to the spectrum of host species, organs, and cells susceptible and permissive to viral infection . It is a potent driver of infection dynamics and shedding patterns, which presents important variations both between and within hosts: in poultry, HPAIV leads to systemic endothelial infection in domestic chickens , whereas neurological and selective epithelial infections are observed in domestic ducks . In mammals , infection can result in respiratory and neurological disease , but the recent outbreaks in domestic dairy cows highlighted a unique and remarkable adaptation to the mammary gland prone to viral shedding in milk. The present review explores viral tropism of HPAIV across recent spillov...

Abstract The November 2021 introduction of highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b into North America triggered a devastating outbreak , affecting more than 180 million domestic birds and spreading to more than 80 wildlife species across Canada and the US . From this outbreak, we have sequenced 2955 complete A( H5N1 ) viral genomes from samples collected in Canada and, in conjunction with previously published data, performed multifaceted phylodynamic analyses. These analyses reveal extensive diversification of A(H5N1) viruses via reassortment with low-pathogenic avian influenza viruses. We find evidence of repeated ancestral strain replacement by direct descendants, indicative of compounding viral fitness increases . Spatiotemporal modeling identified critical geographic areas facilitating transcontinental spread and demonstrated genotype-specific host dynamics, offering essential data for ongoing control and prevention strategies. Source: Science Advances,  https:...

Summary The recent emergence of highly pathogenic H5N1 avian influenza virus infections in dairy cows and humans in the U.S. has raised alarms regarding the potential for a pandemic . Over 995 dairy cow herds and at least 70 humans have been affected, including cases of severe disease and the first reported H5N1-related death in the U.S . Sporadic human infections with no known contact with infected animals highlight the possibility of viral adaptation for efficient human-to-human transmission. Concurrently, the virus continues to circulate in wild birds, backyard flocks, and hunted migratory species , further amplifying the risk to humans and domestic animals. This article provides an overview of the current outbreak status , emphasizes the importance of robust surveillance systems to detect emerging strains with pandemic potential, and highlights risks to the U.S. dairy and poultry industries. Recommendations for risk mitigation include enhanced biosecurity measures, improved surveil...

Abstract Despite identification of Highly Pathogenic Avian Influenza viruses nearly 75 years ago, the transmission pathways among wild animals remain incompletely described. We propose the use of social networks , to complement phylodynamic modeling , for better surveillance, prediction, and prioritization of HPAI. Source: PLoS Pathogens,  https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1013233 ____

Abstract Zoonotic diseases pose global public health threats, prompting various interventions to limit their emergence and spread . One increasingly common response by governments has been to ban wildlife hunting , trade and consumption. However, there is limited evidence of the effectiveness of wildlife trade bans . Here we assess compliance with Nigeria’s wildlife trade ban—enacted to curb the spread of mpox (formerly monkeypox)—by analysing approximately 4.5 years of wild meat sales data from 19 vendors in southeast Nigeria (988 vendor-months) alongside interviews with vendors and law enforcement officials. After matching the sales data by time of year, we found no significant differences before and after the ban in the number of vendors selling wild meat per week, the weekly mass of wild meat sold, or the weekly price per kilogram of wild meat; however, the total weekly sales price was higher post-ban. These findings, supported by interview insights, indicate widespread non-complia...

Abstract The Highly Pathogenic Avian Influenza Virus (HPAIV) H5 clade 2.3.4.4b has caused severe outbreaks in domestic and wild birds worldwide since its emergence in 2014, and especially since 2020, with outbreaks in Europe and North America . The introduction of the virus into South America was reported for the first time in Colombia in October 2022, followed by outbreaks in other South American countries affecting poultry, wild birds, mammals , and humans . In this study, a phylogenetic and mutation analysis of the hemagglutinin (HA) gene of HPAIV H5N1 2.3.4.4b viruses isolated in South America was performed to analyze its evolution and its transmission and zoonotic potential . The analysis shows an increase in the viral effective population size between April and June 2022, which was followed by multiple outbreaks of HPAIV H5N1 clade 2.3.4.4b in South America . Moreover, the virus variants evolved from a recent common ancestor estimated to have existed in June 2017. The mean rate o...

Simple Summary The present commentary deals with the pandemic risk brought about by the highly pathogenic avian influenza (HPAI) A(H5N1) virus . Such a pandemic alarm is justified, among others, by the progressively and rapidly expanding range of virus-susceptible hosts , including humans alongside a significant number of domestic and wild avian and mammalian species , several of which appear to be geographically and phylogenetically distant from each other. Despite its well-established zoonotic potential , no clear-cut evidence of a sustained and efficient HPAI A(H5N1) virus interhuman transmission has thus far been reported. Should this happen in a more or less near future, it could pave the way for a new pandemic. Based upon the above, a “ One Health, One Earth, One Ocean ”-focused, holistic approach would be the necessary prerequisite to deal in an appropriate way with the HPAI A(H5N1) virus-associated zoonotic and pandemic risk. Abstract The focus of this commentary is represented...

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 Free-ranging white-tailed deer (WTD) are highly susceptible to the SARS-CoV-2 virus . Through an opportunistic sampling of WTD in northeast Ohio, USA , during January–March 2023 , we identified 6 SARS-CoV-2 lineages from 36 sequences using the pangolin lineages tool, including the B.1.1.7 lineage (Alpha variant) and BQ.1.1, BQ.1.1.63, BQ.1.1.67, BQ.1.23, and XBB.1.5.35 lineages ( Omicron variant ). The Alpha variant, introduced by a single human-to-deer transmission event , was detected in 5 WTD in January 2023, more than 1 year after the most recent detection of the Alpha variant in humans in Ohio (August 2021). A genetically similar B.1.1.7 lineage virus from WTD in a nearby county in Pennsylvania was positioned with our Ohio deer transmission cluster, suggesting deer-to-deer transmission . The persistence of the Alpha variant in WTD in Ohio warrants continued surveillance to monitor if WTD can become a reservoir for displaced SARS-CoV-2 variants. Source: US Centers for Dise...

Abstract Avian influenza viruses (AIVs) pose a growing global health threat , particularly in low- and middle-income countries (LMICs), where limited surveillance capacity and under-resourced healthcare systems hinder timely detection and response. Migratory birds play a significant role in the transboundary spread of AIVs, yet data from key regions along migratory flyways remain sparse. To address these surveillance gaps, we conducted a study between December 2021 and February 2023 using fresh bird guano collected across 10 countries in the Global South . Here, we show that remote, uninhabited regions in previously unsampled areas harbor a high diversity of AIV strains , with H5N1 emerging as the most prevalent . Some of these H5N1 samples also carry mutations that may make them less responsive to the antiviral drug oseltamivir . Our findings documented the presence of AIVs in several underrepresented regions and highlighted critical transmission hotspots where viral evolution may be ...

Abstract In this work, we performed the genetic characterization of a new variant of orthohantavirus associated with a fatal case of hantavirus pulmonary syndrome , outside the known endemic region, in northwestern Argentina . We first confirmed an orthohantavirus infection by ELISA , testing for the detection of IgM and IgG antibodies. Then, we extracted RNA from 100 microliters of serum, the only sample available, followed by RT-PCR. The amplicons were sequenced using Sanger and next-generation sequencing technology. We obtained partial sequences of 1253 bp, 799 bp and 1675 bp from the S-, M- and L-segments, respectively, showing low sequence identities with all the previously characterized hantaviruses (10.9%, 13.5% and 15.1% of the divergence, respectively). The phylogenetic analysis showed that this virus belongs to the Orthohantavirus andesense species (ANDV), and among the ANDV-like variants, it is more closely related to the Lechiguanas clade . Similar percentages of divergence...

 Two wild servals in Dhaka Region. Source: WOAH,  https://wahis.woah.org/#/in-review/6453 ____

 A Red Fox in Tromso Region. Source: WOAH,  https://wahis.woah.org/#/in-review/6450 ____

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 Background In 2021, the H5N1 clade 2.3.4.4b Avian Influenza Viruses (AIVs) emerged on the American continent. At the same time, a further global spread took place. Infections have been reported in avian species as well as in over 50 mammalian species in 26 countries , and often result in severe disease with notable neurological pathology . Outbreaks in dairy cattle in the United States in 2024 illustrate viral transmission at a non-traditional interface and cross-species transmission. This development raises significant global concern regarding the virus's potential for wider spread. Given that H5N1 infections in birds reached record-high levels in Germany by late 2022, it is important to investigate whether Influenza A Virus (IAV) infections were also occurring in mammals sharing habitats with wild birds. Methods and Results Selected wild and domestic mammal populations were monitored over a two-year period (from January 2022 to December 2023), which coincided with a majo...