#Outdoor roaming of owned #cats elevates #risk of zoonotic #pathogen #exposure: A global synthesis

 

Abstract

Domestic animals play a central role in pathogen transmission at the human–wildlife interface. Domestic cats, in particular, are uniquely consequential in disease spillover dynamics due to their global distribution, large, human-subsidized free-roaming populations, and high contact rate with humans, domestic animals, and wildlife. However, the extent to which human ownership and management mitigate this spillover risk remains a key knowledge gap. To address this gap, we conducted a global systematic review and quantitative synthesis of the prevalence and diversity of zoonotic pathogens in indoor-only, outdoor-owned (roaming unsupervised), and unowned (feral or stray) cats. Our dataset comprised 174,064 individuals from 88 countries, representing 124 pathogen species, 97 of which are zoonotic. Using generalized linear models within a Bayesian framework and rarefaction analyses, we show that ownership provides limited protection against zoonoses when owned cats have unsupervised outdoor access. Outdoor-owned cats were 3–5 times more likely to carry zoonotic pathogens than indoor-only cats, and, notably, had infection odds statistically equivalent to those of feral cats, despite receiving presumed veterinary care and feeding. Feral cats carried the highest pathogen diversity, however, outdoor-owned cats still harbour 1.5 times the helminth richness of indoor cats, highlighting their potential as effective bridges for pathogen spillover. With approximately 62% of owned cats roaming freely worldwide, and rates exceeding 90% in some regions, these findings reveal a major yet overlooked route of zoonotic risk. Public health and One Health frameworks have traditionally focused on feral cats; however, our results highlight the need to explicitly incorporate owned outdoor cats into zoonotic disease prevention strategies by restricting unsupervised roaming and promoting responsible ownership practices. Without such integration, current frameworks risk overlooking a pervasive and preventable pathway for pathogen transmission at the human–wildlife–domestic animal interface.

Source: 

Link: https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1014160

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ONWARD: a #OneHealth, pan - #European multidisciplinary #network advancing #surveillance, #research, clinical management and control of zoonotic #hepeviruses

 

Highlight

• HEV remains the leading cause of acute viral hepatitis in Europe

• Surveillance and diagnostics for HEV are heterogeneous across EU/EEA

• Zoonotic HEV circulates widely in pigs, wildlife and food chains

• Rat HEV expands the zoonotic spectrum and clinical burden in Europe

• ONWARD integrates One Health surveillance, research and capacity building

Abstract

Zoonotic hepeviruses, particularly hepatitis E virus (HEV, species Paslahepevirus balayani) represent a major yet underestimated public health challenge in Europe. Despite being the leading cause of acute viral hepatitis, surveillance, diagnostic practices and prevention strategies remain heterogeneous across EU/EEA countries, limiting comparability and hindering accurate burden estimates. Underdiagnosis is further compounded by extrahepatic manifestations and the growing impact of chronic HEV infection in immunocompromised patients. At the human–animal–environment interface, zoonotic HEV circulates widely in domestic pigs, wildlife and food products, while coordinated surveillance and control measures remain inconsistently implemented. The recent recognition of ratHEV (species Rocahepevirus ratti) as a cause of acute and chronic hepatitis in Europe further expands the spectrum of zoonotic hepevirus infections and underscores the need for integrated One Health approaches. To address these challenges, the One Health Zoonotic Hepevirus Network (ONWARD; COST Action CA24140) was launched in 2025 as a pan-European, multidisciplinary collaboration uniting experts across human, veterinary, food safety and environmental health sectors. ONWARD aims to harmonise diagnostic tools, strengthen clinical research, integrate multisectoral surveillance, promote capacity building and support evidence-based policy development. By fostering coordination with European stakeholders ONWARD provides a structured framework to strengthen preparedness, surveillance and response to zoonotic hepevirus threats across Europe.

Source: 

Link: https://www.sciencedirect.com/science/article/pii/S1386653226000338?dgcid=rss_sd_all

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Mapping #global emergence of #pathogens with #epidemic and #pandemic #potential to inform and accelerate pandemic #prevention, #preparedness, readiness and response

 

Abstract

Introduction 

Increasing occurrence of epidemics and pandemics and concurrent emergence of different pathogens calls for multi-sectoral, multi-pathogen preparedness actions. Data on various factors that drive emergence of diverse pathogens can inform evidence-based preparedness by identifying geographies at-risk. When leveraging evidence within a One Health approach, multiple pathogens can be addressed simultaneously, thereby strengthening countries pandemic preparedness efforts. 

Methods 

For seventeen priority pathogens (avian influenza viruses, zoonotic coronaviruses including COVID-19, hemorrhagic fever viruses including Ebola, Henipaviruses, and arboviruses including yellow fever and Zika), we identified global evidence on animal reservoirs, vectors, environmental suitability, and reported human cases. We discriminated geospatially recorded pathogen detections from a background sample and constructed maps using these datasets to generate an evidence-based assessment of emergence risk globally. 

Results 

Seventeen pathogen-specific assessments were combined into a global composite map. Sub-Saharan Africa and South Asia have evidence supporting emergence risk for the greatest number of pathogens (included areas at-risk of all pathogens) and scored highest when strength-of-evidence weightings were factored. The Americas had the lowest tally of considered pathogens. Environmental suitability analyses received the highest weights, reservoir ranges the lowest. 

Discussion 

Preparedness and readiness must consider the range of global biological threats. Our methodology is capable of incorporating changing evidence on emergence potential for multiple pathogens to identify geographies at higher risk with different pathogen combinations. Our maps can contribute to existing decision-support structures, guiding shared interventions and strategic allocation of resources for spillover prevention and pandemic preparedness, thereby enhancing local response capacities applying a multidisciplinary approach.

Competing Interest Statement

The authors have declared no competing interest.

Funding Statement

This work was concluded in 2024 and supported by the United States Agency for International Development (USAID) before January 22, 2025, the Germany Agency for International Cooperation (GIZ) and the Government of France.

Source: 

Link: https://www.medrxiv.org/content/10.64898/2026.03.20.26347940v1

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Efficient #replication of #influenza D virus in the #human #airway underscores zoonotic potential

 

Abstract

Influenza D virus (IDV), primarily found in livestock species, has demonstrated cross-species transmission potential, yet its threat to humans remains poorly understood. Here, we curated a panel of IDV isolates collected during field surveillance from 2011 to 2020 from swine and cattle to assess their ability to infect human airway cells as a proxy for zoonotic threat assessment. Using lung epithelial cell lines, primary well-differentiated airway epithelial cultures, and precision-cut lung slices, we demonstrated that IDV efficiently propagates in cells and tissues from the human respiratory tract, reaching titers comparable to human influenza A virus (IAV). Infection kinetics in primary porcine airway cultures and respiratory tissues mirrored those from human, suggesting similar infectivity across species. To define host responses to IDV infection, we evaluated innate immune sensing and downstream interferon signaling in human respiratory cells. IDV infection resulted in markedly reduced activation of interferon regulatory factor (IRF) signaling and diminished induction of interferon lambda 1 and interferon-stimulated genes compared to IAV, indicating inefficient activation of innate immune sensing pathways. However, IDV replication was potently restricted in interferon-pretreated cells, demonstrating sensitivity to interferon-mediated antiviral effector mechanisms once an antiviral state was established. Together, these findings show that IDV can efficiently infect the human airway while limiting innate immune sensing, a feature that may facilitate zoonotic spillover. Our study highlights the need for enhanced surveillance of IDV at the animal-human interface and provides a foundation for further investigation into its biology and potential for causing human infection and disease.

Competing Interest Statement

The author E.M.K. is currently employed by AbbVie Inc. The author was not affiliated with AbbVie Inc at the time of experiment design, data acquisition, or analysis.

Funder Information Declared

United States Department of Agriculture (USDA) National Institute of Food and Agriculture (NIFA), 2025-39601-44639

The Enterprise for Research, Innovation, and Knowledge at The Ohio State University

Centers of Excellence for Influenza Research and Response, National Institute of Allergy and Infectious Diseases, National Institutes of Health (NIH), Department of Health and Human Services, HHSN272201400006C, 75N93021C00016

National Institutes of Health, T35 5T35OD010977

National Institutes of Health, P30 CA016058

Source: 

Link: https://www.biorxiv.org/content/10.64898/2026.02.07.704474v1

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From #pandemic #influenza to novel #coronaviruses: emerging infectious diseases of the 21st century

 

Highlights

• Global mobility, climate pressures, and ecological change drive emerging infections.

• Highly pathogenic influenza strains, including H5N1, pose ongoing spillover risks and pandemic potential.

• SARS, MERS, and COVID-19 illustrate the pandemic potential of novel coronaviruses.

• Nipah, Ebola, Pteropine orthoreovirus and Zika remain high-impact threats for global health security.

• Mass gatherings can amplify transmission risks of emerging high-consequence viruses.

• Strengthened surveillance, diagnostics, and One Health strategies are essential for pandemic preparedness.

Abstract

Emerging infectious diseases have risen significantly in the twenty-first century as ecological disruption, climate change, expanding human–animal interfaces, and global mobility intensify opportunities for pathogen transmission. This review synthesizes historical and contemporary evidence across viral, bacterial, fungal, and parasitic threats to characterize how diverse pathogens emerge and spread. Foundational events such as the 1918 influenza pandemic, mid-century influenza pandemics, the emergence of HIV/AIDS, and the eradication of smallpox provide context for understanding modern disease dynamics. In recent decades, coronaviruses including SARS, MERS, and SARS-CoV-2, pandemic H1N1, avian influenza subtypes, and major arboviruses such as dengue, chikungunya, Zika, West Nile virus, and yellow fever have demonstrated the rapidity with which zoonotic pathogens can disseminate globally. Viral hemorrhagic fevers including Ebola, Marburg, Lassa, and Crimean–Congo hemorrhagic fever remain critical threats, especially in regions with limited health-care capacity. Concurrently, antimicrobial resistance, the emergence of Candida auris, and the climate-driven expansion of endemic mycoses involving Histoplasma, Coccidioides, and Blastomyces highlight the increasing importance of fungal pathogens. Parasitic diseases such as artemisinin-resistant malaria, zoonotic trypanosomiasis, and expanding Leishmania transmission reflect shifting ecological conditions. These patterns are shaped by intersecting drivers including deforestation, wildlife trade, agricultural intensification, urban crowding, conflict, and rapid microbial evolution that enable spillover and sustained transmission. Although advances in genomic surveillance, metagenomic diagnostics, mRNA vaccines, monoclonal antibodies, and broad-spectrum antivirals have strengthened global response capacity, substantial gaps persist in equity, surveillance, and access to countermeasures. Strengthening One Health systems and resilient public health infrastructures is essential to anticipate and mitigate emerging infectious threats.

Source: 

Link: https://www.sciencedirect.com/science/article/abs/pii/S0732889326000271?via%3Dihub

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Phylogenetic Characteristics and High Prevalence of a #Merbecovirus in #Hedgehogs from Greenspace of a Metropolis, #China

 

Abstract

SARS-CoV, MERS-CoV, and SARS-CoV-2 have posed tremendous threats to human health, highlighting the necessity of monitoring cross-species transmission of animal coronaviruses to humans. Hedgehogs infected with coronaviruses have been reported in several countries across Europe and Asia, raising concerns about the potential transmission of coronaviruses from hedgehogs to humans. In this study, we investigated coronavirus infections in hedgehogs inhabiting greenspaces in metropolitan Beijing and identified a Merbecovirus subgenus coronavirus with a prevalence rate of 30% (95% CI: 25–35%) among 317 hedgehogs. Phylogenetic analysis of 23 complete viral genome sequences revealed a monophyletic origin, showing close relatedness to Erinaceus hedgehog coronavirus HKU31 (Ea-HedCoV HKU31) with genome-wide nucleotide identities of 93.24–96.42%, and evidence of recombination with Tylonycteris bat coronavirus HKU4. These findings suggest that the increase in wildlife populations associated with urban greenspace development may pose a potential threat to human health that should not be overlooked.

Source: 

Link: https://www.mdpi.com/2076-2607/14/1/83

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A #Market-Based #Sentinel #Surveillance for an Early #Detection of Viral #Outbreaks

 

Abstract

Mexico has experienced recurrent viral epidemics of substantial intensity, including hyperendemic dengue, COVID-19, and recent reports of avian influenza A (H5N1) infections in birds, which pose an ongoing risk of zoonotic transmission. Mexico was also the location for the earliest detection of the pdmH1N1 virus during the 2009 influenza A pandemic. Under a One Health framework, markets represent a unique opportunity for low-cost virus monitoring at the human-animal interface. Under the hypothesis that these represent sentinel sites for an early virus detection, we implemented a pilot surveillance program at the central market of Merida city, Yucatan, Mexico, considered a regional hotspot for multiple and recent viral outbreaks. Longitudinal sampling was carried out over 11 months at 1-to-6-week intervals from April 2022 to February 2023. We used multi-type surveillance in mosquitoes, live poultry, and wastewater. All samples were screened using RT-qPCR. Positive samples for DENV, SARS-CoV-2 and avian influenza A were further sequenced and analysed under a phylogenetic and epidemiological approach. Through our entomological surveillance, we report the earliest detection of DENV-3 III-B3.2 (genotype III American II lineage, considered a major public health concern in Latin America) in Mexico, overlapping with the resurgence of DENV-3 as the predominant serotype driving the 2023 national epidemic, which showed an increased severity. Through wastewater surveillance, we consistently detect SARS-CoV-2 RNA in wastewater samples, coinciding with the two infection waves officially recorded at a city and state level. Finally, cloacal swabs taken from two juvenile birds at the market suggest that avian influenza A viruses circulated in live poultry sold at the market. These findings show that our market-based surveillance framework is effective for an early detection and monitoring of pathogenic viruses in urban settings, and could complement official epidemiological surveillance in low- and middle-income countries to strengthen early-outbreak warning systems.

Competing Interest Statement

The authors have declared no competing interest.

Funding Statement

This study was supported by the John Fell OUP Research Grant ATD00390 (M.E.Z and M.U.G.K), the Wellcome Infectious Disease Award ?317324/Z/24/Z (M.G.K, H.P.G and M.E.Z), the Secretaria de Ciencia, Humanidades, Tecnología e Inovación award (SECIHTI, Mexico) through the PRONACES Health grant (PRONAII project number 303002, G.S) and the Ciencia Básica y de Frontera programme (CBF2023-2024-3184, M.G.K), and the UKRI Innovation BSRC/EPSRC/NIHR 971557 grant (A.R.S). M.G.K is funded through a Sanger International Fellowship award. M.E.Z is funded by a UCL Rosetrees Excellence Fellowship UCL2024\2. P.M.D was funded through the doctoral program at ‘Posgrado en Ciencias de la Produccion y de la Salud Animal-UNAM’ through the SECIHTI doctoral scholarship. M.U.G.K. acknowledges funding from The Rockefeller Foundation (PC-2022-POP-005), Health AI Programme from Google.org, the Oxford Martin School Programmes in Pandemic Genomics & Digital Pandemic Preparedness, European Union's Horizon Europe programme projects MOOD (#874850) and E4Warning (#101086640), Wellcome Trust grants 303666/Z/23/Z, 226052/Z/22/Z & 228186/Z/23/Z, the United Kingdom Research and Innovation (#APP8583), the Medical Research Foundation (MRF- RG-ICCH-2022-100069), UK International Development (301542-403), the Bill & Melinda Gates Foundation (INV-063472) and Novo Nordisk Foundation (NNF24OC0094346). B.G is further funded by Wellcome Trust grants 303666/Z/23/Z, 226052/Z/22/Z & 228186/Z/23/Z. The contents of this publication are the sole responsibility of the authors and do not necessarily reflect the views of the European Commission or the other funders. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Source: 

Link: https://www.medrxiv.org/content/10.64898/2025.12.22.25342882v1

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#Mammalian #adaptation and zoonotic #risk of #influenza A viruses in companion #animals

 

Abstract

Importance

Since the early 2000s, companion animals emerged as unexpected players in influenza A virus ecology. Canine influenza viruses and the increasing detection of highly pathogenic avian influenza viruses in cats have raised concerns about their potential role as intermediate hosts for pandemic emergence. Their unique position at human-animal interface creates unprecedented opportunities for viral evolution and bidirectional transmission between humans and animals.

Observations

This review examined the transmission pathways and molecular adaptations of influenza A virus in companion animals. Cats primarily acquire infections through alimentary routes, including consumption of raw poultry and unpasteurized milk, as well as environmental exposure through hunting. Dogs transmit influenza viruses via respiratory droplets in high-density settings such as shelters and kennels. Canine influenza viruses demonstrate successful mammalian adaptation through accumulated mutations across multiple viral proteins, particularly in polymerase and hemagglutinin genes, enabling sustained dog-to-dog transmission. Feline isolates consistently exhibit mammalian adaptive mutations across geographically disparate outbreaks. Several molecular changes appear convergently in both species, suggesting shared evolutionary pressures at companion animal-human interface.

Conclusions and Relevance

Despite molecular evidence of active viral evolution, companion animals currently pose a limited pandemic risk owing to no sustained zoonotic transmission chains. Critical knowledge gaps remain regarding subclinical infection frequency, natural transmission efficiency, and host genetic factors that influence susceptibility. Surveillance should prioritize high-risk interfaces, including raw pet food supply chains and veterinary facilities, while maintaining the perspective of actual versus theoretical risks. Understanding companion animal influenza virus dynamics is essential for comprehensive pandemic preparedness strategies.

Source: 

Link: https://vetsci.org/DOIx.php?id=10.4142/jvs.25153

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Monitoring #zoonoses to prevent future #outbreaks and #pandemics

 

Abstract

Most emerging human infectious diseases are derived from animals, and monitoring such zoonoses is imperative to help prevent future outbreaks. In this Forum, we discuss the knowledge gaps in our current understanding of viral ecology, global disparities in virus discovery, and the applications of artificial intelligence in infectious disease monitoring.

Source: Cell Host & Microbe, https://www.cell.com/cell-host-microbe/abstract/S1931-3128(25)00429-9?rss=yes

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#Genetic characterization of the #marmot gut #virome in high-altitude #Qinghai Province and identification of novel #viruses with zoonotic potential

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 formed a distinct clade within the Dependoparvovirus genus. The discovery of a novel astrovirus with low sequence similarity to known genera underscores the need for taxonomic reclassification. Additionally, a novel picornavirus related to Sapelovirus and four divergent CRESS DNA viruses were identified, expanding our understanding of viral diversity in high-altitude rodents. These findings emphasize the role of marmots as viral reservoirs and highlight the importance of high-altitude ecosystems as hotspots for zoonotic pathogen emergence. This study provides critical insights into viral evolution, host adaptation, and zoonotic risks, advocating for integrated surveillance strategies to mitigate future spillover events.

IMPORTANCE

Viruses are the most abundant and diverse biological entities on Earth, yet their presence in wildlife from extreme environments remains poorly understood. High-altitude ecosystems, shaped by harsh conditions like intense UV radiation and low oxygen levels, create unique settings for virus evolution. This study is the first to comprehensively profile the gut virome of marmots in Qinghai Province, uncovering novel viral strains and highlighting how extreme environments drive viral diversity. Marmots, as key species in these regions, can act as bridges for virus transmission among wildlife, livestock, and humans, posing zoonotic risks. Understanding these viral communities is essential for predicting and preventing future outbreaks. Our findings emphasize the urgent need for integrated, One Health-based surveillance strategies to safeguard both public health and biodiversity in fragile high-altitude ecosystems.

Source: mSphere, https://journals.asm.org/doi/full/10.1128/msphere.00297-25?af=R

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Weak #compliance with #Nigeria’s #wildlife #trade ban imposed to curb #mpox #spillovers

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-compliance by vendors, questioning the ban’s effectiveness. We propose that successful regulations require clear enforcement mechanisms, active public engagement and economic incentives to improve compliance. This study provides valuable insights for designing effective interventions to mitigate zoonotic spillovers.

Source: Proceedings of the Royal Society, Biological Sciences, https://royalsocietypublishing.org/doi/full/10.1098/rspb.2025.0471

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Discovery of a Novel #Parahenipavirus, Parahenipavirus_GH, in #Shrews in South #Korea, 2022

Abstract

Highly pathogenic henipaviruses (Nipah and Hendra viruses) and parahenipaviruses (Langya virus) have demonstrated significant zoonotic potential. We aimed to identify Henipavirus or Parahenipavirus species in rodents and shrews in South Korea to underline the potential zoonotic transmission risk. Kidney and lung tissues from 285 rodents and shrews were screened for Henipavirus and Parahenipavirus using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) targeting the Gamak virus and Daeryong virus (DARV) sequences. Based on the qRT-PCR results, 75 out of the 285 individuals tested positive, with the highest viral loads in the kidneys of Apodemus agrarius, Crocidura lasiura, and Crocidura shantungensis. A kidney sample from C. shantungensis that exhibited the lowest Ct value was further analyzed using PCR, Sanger sequencing, and metagenomic analysis, yielding a near-complete genome of a novel Parahenipavirus, designated Parahenipavirus_GH (PHNV-GH), which is phylogenetically related to DARV and Jingmen virus but exhibits distinct genomic features. Ixodes granulatus ticks were also identified on the host shrew. The identification of PHNV-GH in southern South Korea expands the known geographical distribution range of parahenipaviruses and highlights the ongoing risk of zoonotic transmission. Given the uncertain transmission dynamics and pathogenic potential of parahenipaviruses, comprehensive environmental surveillance and characterization of emerging parahenipaviruses are essential for preventing future outbreaks.

Source: Viruses, https://www.mdpi.com/1999-4915/17/6/867

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#Pigeons exhibit low susceptibility and poor #transmission capacity for #H5N1 clade 2.3.4.4b high pathogenicity avian #influenza virus

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 develop clinical signs, and only those inoculated with the highest dose shed viral RNA or seroconverted to H5N1-AB, revealing a MID50 of 10^5 EID50. Even in the high dose group, only low-level shedding and environmental contamination was observed, and low-level viral RNA were present in the tissues of directly inoculated pigeons, with no distinct pathological lesions. Pigeons did not transmit the virus to naive pigeons or chickens placed in direct contact. Overall, these findings suggest that pigeons have a low susceptibility to clade 2.3.4.4b H5N1 HPAIV and are less likely to significantly contribute to disease ecology, incursions into poultry, or pose a significant zoonotic threat.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.05.02.651910v1

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Modelling a potential #zoonotic #spillover event of #H5N1 #influenza

Abstract

Highly Pathogenic Avian Influenza (HPAI) is a prominent candidate for a future human pandemic arising from a zoonotic spillover event. Its best-known strain is H5N1, with South- or South-East Asia a likely location for an initial outbreak. Such an outbreak would be initiated through a primary event of bird-to-human infection, followed by sustained human-to-human transmission. Early interventions would require the extraction, integration and interpretation of epidemiological information from the limited and noisy case data available at outbreak onset. We studied the implications of a potential zoonotic spillover of H5N1 influenza into humans. Our simulations used BharatSim, an agent-based model framework designed primarily for the population of India, but which can be tuned easily for others. We considered a synthetic population representing farm-workers (primary contacts) in a farm with infected birds. These primary contacts transfer infections to secondary (household) contacts, from where the infection spreads further. We simulate outbreak scenarios in such a setting, accounting for the network structure of human contacts and the stochasticity of the infection process. We further simulated multiple interventions, including bird-culling, quarantines, and vaccinations. We show how limited, noisy data for primary and secondary infections can be used to estimate epidemiological transmission parameters, such as the basic reproductive ratio R0, in realistic settings. We describe the impact of early interventions (bird-culling, quarantines, and vaccination), taken together or separately, in slowing or terminating the outbreak. An individual-based model allows for the most granular description of the bird-human spillover and subsequent human-to-human transmission for the case of H5N1. Such models can be contextualised to individual communities across varied geographies, given representative contact networks. We show how such models allow for the systematic real-time exploration of policy measures that could constrain disease-spread, as well as guide a better understanding of disease epidemiology.

Source: MedRxIV, https://www.medrxiv.org/content/10.1101/2025.04.28.25326570v1

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A #Wildlife #Health #Outbreak #Response Table-top Exercise for #Pandemic Preparedness #Planning

Abstract

Zoonotic diseases have received significantly more attention over the last few decades, emerging with increasing frequency and causing the majority of notable disease outbreaks in this century, including the COVID-19 pandemic. As human activities and shifting climate patterns induce changes in the environment that alter habitat and range of reservoir species, the potential for human and animal interactions will increase and enhance the opportunity for spillover. Thus, any emergency response preparedness planning must take into account the function and coordination of agencies across the sectors of human, animal and environmental health. Within the Commonwealth of Pennsylvania a table-top exercise was performed to evaluate a multi-agency response during a hypothetical zoonotic disease investigation. The exercise was evaluated by the participants to gain feedback on the overall process and lessons learned. Here, we describe the tabletop exercise scenario and the insights gained. We found that differences in operational structure create challenges for interdepartmental communication and in the ability to resource a coordinated response, highlighting opportunities to develop infrastructure that will facilitate future actions. A set of recommendations are outlined that may enhance cross-agency activities and promote more effective and efficient emergency response.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.04.01.646690v1

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Post-pandemic #changes in #population #immunity have reduced the likelihood of emergence of #zoonotic #coronaviruses

Abstract

Infections caused by endemic viruses, and the vaccines used to control them, often provide cross-protection against related viruses. This cross-protection has the potential to alter the transmission dynamics and likelihood of emergence of novel zoonotic viruses with pandemic potential. Here, we investigate how changes in population immunity after the COVID-19 pandemic have impacted the likelihood of emergence of a novel sarbecovirus, termed SARS-CoV-X. We show that sera from patients with different COVID-19 immunological histories possess cross-neutralising antibodies against the spike (S) protein of multiple zoonotic sarbecoviruses. Mathematical simulations using these viruses show a significant reduction in their likelihood of emergence in populations with current levels of SARS-CoV-2 natural and vaccine-derived immunity, with the outcome determined by the extent of cross-protection and the R_0 of the novel virus. We also show that preventative vaccination programs against SARS-CoV-X using currently available COVID-19 vaccines can help resist emergence even in the presence of co-circulating SARS-CoV-2. However, it was possible for a theoretical vaccine with very high specificity to SARS-CoV-2 (i.e., one which elicits very low cross-protection against SARS-CoV-X) to increase the likelihood of SARS-CoV-X emergence, due to its effects on SARS-CoV-2 prevalence and, by extension, the levels of naturally-derived cross-protection in the human population. Overall, our findings show that SARS-CoV-2 circulation and COVID-19 vaccination have generated widespread population immunity against antigenically related sarbecoviruses, and this new immunological barrier is likely to be a strong determinant of the ability of novel sarbecoviruses to emerge in humans.

Source: MedRxIV, https://www.medrxiv.org/content/10.1101/2025.03.17.25323820v1

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Dynamics of natural #selection preceding #human viral #epidemics and #pandemics.

Abstract

Using a phylogenetic framework to characterize natural selection, we investigate the hypothesis that zoonotic viruses require adaptation prior to zoonosis to sustain human-to-human transmission. Examining the zoonotic emergence of Ebola virus, Marburg virus, influenza A virus, SARS-CoV, and SARS-CoV-2, we find no evidence of a change in the intensity of natural selection immediately prior to a host switch, compared with typical selection within reservoir hosts. We conclude that extensive pre-zoonotic adaptation is not necessary for human-to-human transmission of zoonotic viruses. In contrast, the reemergence of H1N1 influenza A virus in 1977 showed a change in selection, consistent with the hypothesis of passage in a laboratory setting prior to its reintroduction into the human population, purportedly during a vaccine trial. Holistic phylogenetic analysis of selection regimes can be used to detect evolutionary signals of host switching or laboratory passage, providing insight into the circumstances of past and future viral emergence.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.02.26.640439v1

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Novel #human #coronavirus in an #infant #patient with #pneumonia, Republic of #Korea

ABSTRACT

Coronaviruses (CoVs) pose a significant threat to public health, causing a wide spectrum of clinical manifestations and outcomes. Beyond precipitating global outbreaks, Human CoVs (HCoVs) are frequently found among patients with respiratory infections. To date, limited attention has been directed towards alphacoronaviruses due to their low prevalence and fatality rates. Nasal swab and serum samples were collected from a paediatric patient, and an epidemiological survey was conducted. Retrospective surveillance investigated the molecular prevalence of CoV in 880 rodents collected in the Republic of Korea (ROK) from 2018 to 2022. Next-generation sequencing (NGS) and phylogenetic analyses characterized the novel HCoV and closely related CoVs harboured by Apodemus spp. On 15 December 2022, a 103-day-old infant was admitted with fever, cough, sputum production, and rhinorrhea, diagnosed with human parainfluenza virus 1 (HPIV-1) and rhinovirus co-infection. Elevated AST/ALT levels indicated transient liver dysfunction on the fourth day of hospitalization. Metagenomic NGS (mNGS) identified a novel HCoV in nasal swab and serum samples. Retrospective rodent surveillance and phylogenetic analyses showed the novel HCoV was closely related to alphacoronaviruses carried by Apodemus spp. in the ROK and China. This case highlights the potential of mNGS to identify emerging pathogens and raises awareness of possible extra-respiratory manifestations, such as transient liver dysfunction, associated with novel HCoVs. While the liver injury in this case may be attributable to the novel HCoV, further research is necessary to elucidate its clinical significance, epidemiological prevalence, and zoonotic origins.

Source: Emerging Microbes and Infections, https://www.tandfonline.com/doi/full/10.1080/22221751.2025.2466705

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Comprehensive #Infectome #Analysis Reveals Diverse Infectious Agents with #Zoonotic #Potential in #Wildlife

Abstract

Understanding wildlife-pathogen interactions is crucial for mitigating zoonotic risk. Through meta-transcriptomic sequencing we profiled the infectomes of 1,922 samples from 67 mammalian species across China, uncovering a remarkable diversity of viral, bacterial, fungal, and parasitic pathogens. Of the 195 pathogens identified, 62 were novel, including a bi- segmented coronavirus in diseased lesser pandas, which we propose represents a new genus – Zetacoronavirus. The orders Carnivora and Rodentia exhibited the highest pathogen diversity and were implicated in numerous host-jumping events. Comparative analysis of diseased versus healthy animals revealed a trend of higher pathogen loads in the former, with possible differences in tissue tropisms. In total, 48 zoonotic and 17 epizootic pathogens were identified, with frequent cross-species transmission, emphasizing the potential for emerging public health threats. This study highlights the urgent need for wildlife pathogen surveillance to inform proactive disease management strategies.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.01.09.632079v1

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Rapid #Surge of #Reassortant A(#H1N1) #Influenza Viruses in Danish #Swine and their #Zoonotic Potential

 Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2024.12.11.627926v1?rss=1 

Abstract

In 2018, a single detection of a novel reassortant swine influenza A virus (swIAV) was made in Denmark. The hemagglutinin (HA) of the virus was from the H1N1 pandemic 2009 (H1N1pdm09) lineage and the neuraminidase (NA) from the H1N1 Eurasian avian-like swine lineage (H1N1av). By 2022, the novel reassortant virus (H1pdm09N1av) constituted 27 % of swIAVs identified through the Danish passive swIAV surveillance program. Sequencing detected two H1pdm09N1av genotypes; Genotype 1 contained an internal gene cassette of H1N1pdm09 origin, Genotype 2 differed by carrying an NS gene segment of H1N1av origin. The internal gene cassette of Genotype 2 became increasingly dominant, not only in the H1pdm09N1av population, but also in other Danish enzootic swIAV subtypes. Phylogenetic analysis of the HA genes from H1pdm09N1av viruses revealed a monophyletic source, a higher substitution rate compared to other H1N1pdm09 viruses and genetic differences with human seasonal and other swine adapted H1N1pdm09 viruses. Correspondingly, H1pdm09N1av viruses were antigenically distinct from human H1N1pdm09 vaccine viruses. Both H1pdm09N1av genotypes transmitted between ferrets by direct contact, but only Genotype 1 was capable of efficient aerosol transmission. The rapid spread of H1pdm09N1av viruses in Danish swine herds is concerning for swine and human health. Their zoonotic threat is highlighted by the limited pre-existing immunity observed in the human population, aerosol transmission in ferrets and the finding that the internal gene cassette of Genotype 2 was present in the first two zoonotic infections ever detected in Denmark.

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