Viral zoonotic risk is homogenous among taxonomic orders of mammalian and avian reservoir hosts

Emerging patterns in rodent-borne zoonotic diseases

Rodents are ubiquitous and typically unwelcome dwellers in human habitats worldwide, infesting homes, farm fields, and agricultural stores and potentially shedding disease-causing microbes into the most human-occupied of spaces. Of the vertebrate animal taxa that share pathogens with us, rodents are the most abundant and diverse, with hundreds of species of confirmed zoonotic hosts, some of which have nearly global distributions. However, only 12% of rodent species are known to be sources of pathogens that also infect people, and those rodents that do are now recognized as tending to share a suite of predictable traits. Here, we characterize those traits and explore them in the context of three emerging or reemerging rodent-borne zoonotic diseases of people: Lassa fever, Lyme disease, and plague.

Disease tolerance as immune defense strategy in bats: One size fits all?

Bats are natural reservoirs for zoonotic pathogens, yet the determinants of microbial persistence as well as the specific functionality of their immune system remain largely enigmatic. Their propensity to harbor viruses lethal to humans and/or livestock, mostly in absence of clinical disease, makes bats stand out among mammals. Defending against pathogens relies on avoidance, resistance, and/or tolerance strategies. In bats, disease tolerance has recently gained increasing attention as a prevailing host defense paradigm. We here summarize the current knowledge on immune responses in bats in the context of infection with zoonotic agents and discuss concepts related to disease tolerance. Acknowledging the wide diversity of bats, the broad spectrum of bat-associated microbial species, and immune-related knowledge gaps, we identify research priorities necessary to provide evidence-based proofs for disease tolerance in bats. Since disease tolerance relies on networks of biological processes, we emphasize that investigations beyond the immune system, using novel technologies and computational biology, could jointly advance our knowledge about mechanisms conferring bats reservoir abilities. Although disease tolerance may not be the "one fit all" defense strategy, deciphering disease tolerance in bats could translate into novel therapies and inform prevention of spillover infections to humans and livestock.

Genetic diversity and cross-species transmissibility of bat-associated picornaviruses from Spain

BACKGROUND

Emerging zoonotic diseases arise from cross-species transmission events between wild or domesticated animals and humans, with bats being one of the major reservoirs of zoonotic viruses. Viral metagenomics has led to the discovery of many viruses, but efforts have mainly been focused on some areas of the world and on certain viral families.

METHODS

We set out to describe full-length genomes of new picorna-like viruses by collecting feces from hundreds of bats captured in different regions of Spain. Viral sequences were obtained by high-throughput Illumina sequencing and analyzed phylogenetically to classify them in the context of known viruses. Linear discriminant analysis (LDA) was performed to infer likely hosts based on genome composition.

RESULTS

We found five complete or nearly complete genomes belonging to the family Picornaviridae, including a new species of the subfamily Ensavirinae. LDA suggested that these were true vertebrate viruses, rather than viruses from the bat diet. Some of these viruses were related to picornaviruses previously found in other bat species from distant geographical regions. We also found a calhevirus genome that most likely belongs to a proposed new family within the order Picornavirales, and for which genome composition analysis suggested a plant host.

CONCLUSIONS

Our findings describe new picorna-like viral species and variants circulating in the Iberian Peninsula, illustrate the wide geographical distribution and interspecies transmissibility of picornaviruses, and suggest new hosts for calheviruses.

Integrative RNA-seq and ChIP-seq analysis unveils metabolic regulation as a conserved antiviral mechanism of chicken p53

The tumor suppressor p53, primarily functioning as a transcription factor, has exhibited antiviral capabilities against various viruses in chickens, including infectious bursal disease virus (IBDV), avian leukosis virus subgroup J (ALV-J), and avian infectious laryngotracheitis virus (ILTV). Nevertheless, the existence of a universal antiviral mechanism employed by chicken p53 (chp53) against these viruses remains uncertain. This study conducted a comprehensive comparison of molecular networks involved in chp53's antiviral function against IBDV, ALV-J, and ILTV. This was achieved through an integrated analysis of ChIP-seq data, examining chp53's genome-wide chromatin occupancy, and RNA-seq data from chicken cells infected with these viruses. The consistent observation of chp53 target gene enrichment in metabolic pathways, confirmed via ChIP-qPCR, suggests a ubiquitous regulation of host cellular metabolism by chp53 across different viruses. Further genome binding motif conservation analysis and transcriptional co-factor prediction suggest conserved transcriptional regulation mechanism by which chp53 regulates host cellular metabolism during viral infection. These findings offer novel insights into the antiviral role of chp53 and propose that targeting the virus-host metabolic interaction through regulating p53 could serve as a universal strategy for antiviral therapies in chickens.IMPORTANCEThe current study conducted a comprehensive analysis, comparing molecular networks underlying chp53's antiviral role against infectious bursal disease virus (IBDV), avian leukosis virus subgroup J (ALV-J), and avian infectious laryngotracheitis virus (ILTV). This was achieved through a combined assessment of ChIP-seq and RNA-seq data obtained from infected chicken cells. Notably, enrichment of chp53 target genes in metabolic pathways was consistently observed across viral infections, indicating a universal role of chp53 in regulating cellular metabolism during diverse viral infections. These findings offer novel insights into the antiviral capabilities of chicken p53, laying a foundation for the potential development of broad-spectrum antiviral therapies in chickens.

Reemergence of a Big Brown Bat Lyssavirus rabies Variant in Striped Skunks in Flagstaff, Arizona, USA, 2021-2023

Background: Throughout the Americas, Lyssavirus rabies (RV) perpetuates as multiple variants among bat and mesocarnivore species. Interspecific RV spillover occurs on occasion, but clusters and viral host shifts are rare. The spillover and host shift of a big brown bat (Eptesicus fuscus) RV variant Ef-W1 into mesocarnivores was reported previously on several occasions during 2001-2009 in Flagstaff, Arizona, USA, and controlled through rabies vaccination of target wildlife. During autumn 2021, a new cluster of Ef-W1 RV cases infecting striped skunks (Mephitis mephitis) was detected from United States Department of Agriculture enhanced rabies surveillance in Flagstaff. The number of Ef-W1 RV spillover cases within a short timeframe suggested the potential for transmission between skunks and an emerging host shift. Materials and Methods: Whole and partial RV genomic sequencing was performed to evaluate the phylogenetic relationships of the 2021-2023 Ef-W1 cases infecting striped skunks with earlier outbreaks. Additionally, real-time reverse-transcriptase PCR (rtRT-PCR) was used to opportunistically compare viral RNA loads in brain and salivary gland tissues of naturally infected skunks. Results: Genomic RV sequencing revealed that the origin of the 2021-2023 epizootic of Ef-W1 RV was distinct from the multiple outbreaks detected from 2001-2009. Naturally infected skunks with the Ef-W1 RV showed greater viral RNA loads in the brain, but equivalent viral RNA loads in the mandibular salivary glands, compared to an opportunistic sample of skunks naturally infected with a South-Central skunk RV from northern Colorado, USA. Conclusion: Considering a high risk for onward transmission and spread of the Ef-W1 RV in Flagstaff, public outreach, enhanced rabies surveillance, and control efforts, focused on education, sample characterization, and vaccination, have been ongoing since 2021 to mitigate and prevent the spread and establishment of Ef-W1 RV in mesocarnivores.

A One Health framework for exploring zoonotic interactions demonstrated through a case study

The eco-epidemiology of zoonoses is often oversimplified to host-pathogen interactions while findings derived from global datasets are rarely directly transferable to smaller-scale contexts. Through a systematic literature search, we compiled a dataset of naturally occurring zoonotic interactions in Austria, spanning 1975-2022. We introduce the concept of zoonotic web to describe the complex relationships between zoonotic agents, their hosts, vectors, food, and environmental sources. The zoonotic web was explored through network analysis. After controlling for research effort, we demonstrate that, within the projected unipartite source-source network of zoonotic agent sharing, the most influential zoonotic sources are human, cattle, chicken, and some meat products. Analysis of the One Health 3-cliques (triangular sets of nodes representing human, animal, and environment) confirms the increased probability of zoonotic spillover at human-cattle and human-food interfaces. We characterise six communities of zoonotic agent sharing, which assembly patterns are likely driven by highly connected infectious agents in the zoonotic web, proximity to human, and anthropogenic activities. Additionally, we report a frequency of emerging zoonotic diseases in Austria of one every six years. Here, we present a flexible network-based approach that offers insights into zoonotic transmission chains, facilitating the development of locally-relevant One Health strategies against zoonoses.

Identifying life-history patterns along the fast-slow continuum of mammalian viral carriers

Life-history traits have been identified as major indicators of mammals' susceptibility and exposure to viruses due to evolutionary constraints that link life-history speed with species' ecology and immunity. Nonetheless, it is unclear where along the fast-slow continuum of mammalian life-history lies the greatest diversity of host species. Consequently, life-history patterns that govern host-virus associations remain largely unknown. Here we analyse the virome of 1350 wild mammals and detect the characteristics that drive species' compatibility with different groups of viruses. We highlight that mammals with larger body size and either very rapid or very slow life histories are more likely to carry different groups of viruses, particularly zoonotic ones. While some common life-history patterns emerge across carriers, eco-evolutionary characteristics of viral groups appear to determine association with certain carrier species. Our findings underline the importance of incorporating both mammals' life-history information and viruses' ecological diversity into surveillance strategies to identify potential zoonotic carriers in wildlife.

Inhibition of Pim kinases triggers a broad antiviral activity by affecting innate immunity and via the PI3K-Akt-mTOR axis the endolysosomal system

Zoonoses such as ZIKV and SARS-CoV-2 pose a severe risk to global health. There is urgent need for broad antiviral strategies based on host-targets filling gaps between pathogen emergence and availability of therapeutic or preventive strategies. Significant reduction of pathogen titers decreases spread of infections and thereby ensures health systems not being overloaded and public life to continue. Based on previously observed interference with FGFR1/2-signaling dependent impact on interferon stimulated gene (ISG)-expression, we identified Pim kinases as promising druggable cellular target. We therefore focused on analyzing the potential of pan-Pim kinase inhibition to trigger a broad antiviral response. The pan-Pim kinase inhibitor AZD1208 exerted an extraordinarily high antiviral effect against various ZIKV isolates, SARS-CoV-2 and HBV. This was reflected by strong reduction in viral RNA, proteins and released infectious particles. Especially in case of SARS-CoV-2, AZD1208 led to a complete removal of viral traces in cells. Kinome-analysis revealed vast changes in kinase landscape upon AZD1208 treatment, especially for inflammation and the PI3K/Akt-pathway. For ZIKV, a clear correlation between antiviral effect and increase in ISG-expression was observed. Based on a cell culture model with impaired ISG-induction, activation of the PI3K-Akt-mTOR axis, leading to major changes in the endolysosomal equilibrium, was identified as second pillar of the antiviral effect triggered by AZD1208-dependent Pim kinase inhibition, also against HBV. We identified Pim-kinases as cellular target for a broad antiviral activity. The antiviral effect exerted by inhibition of Pim kinases is based on at least two pillars: innate immunity and modulation of the endolysosomal system.

Early-stage loss of ecological integrity drives the risk of zoonotic disease emergence

Anthropogenic pressures have increasingly disrupted the integrity of ecosystems worldwide, jeopardizing their capacity to provide essential contributions to human well-being. Recently, the role of natural ecosystems in reducing disease emergence risk has gained prominence in decision-making processes, as scientific evidence indicates that human-driven pressure, such as habitat destruction and deforestation, can trigger the emergence of zoonotic infectious diseases. However, the intricate relationship between biodiversity and emerging infectious diseases (EIDs) remains only partially understood. Here, we updated the most comprehensive zoonotic EID event database with the latest reported events to analyse the relationship between EIDs of wildlife origin (zoonoses) and various facets of ecological integrity. We found EID risk was strongly predicted by structural integrity metrics such as human footprint and ecoregion intactness, in addition to environmental variables such as tropical rainforest density and mammal species richness. EID events were more likely to occur in areas with intermediate levels of compositional and structural integrity, underscoring the risk posed by human encroachment into pristine, undisturbed lands. Our study highlights the need to identify novel indicators and targets that can effectively address EID risk alongside other pressing global challenges in sustainable development, ultimately informing strategies for preserving both human and environmental health.

Prediction of viral spillover risk based on the mass action principle

Infectious zoonotic disease emergence, through spillover events, is of global concern and has the potential to cause significant harm to society, as recently demonstrated by COVID-19. More than 70% of the 400 infectious diseases that emerged in the past five decades have a zoonotic origin, including all recent pandemics. There have been several approaches used to predict the risk of spillover through some of the known or suspected infectious disease emergence drivers, largely using correlative approaches. Here, we predict the spatial distribution of spillover risk by approximating general transmission through animal and human interactions. These mass action interactions are approximated through the multiplication of the spatial distribution of zoonotic virus diversity and human population density. Although our results indicate higher risk in regions along the equator and in Southeast Asia where both virus diversity and human population density are high, it should be noted that this is primarily a conceptual exercise. We compared our spillover risk map to key factors, including the model inputs of zoonotic virus diversity estimate map, human population density map, and the spatial distribution of species richness. Despite the limitations of this approach, this viral spillover map is a step towards developing a more comprehensive spillover risk prediction system to inform global monitoring.

Emergence failure of early epidemics: A mathematical modeling approach

Epidemic or pathogen emergence is the phenomenon by which a poorly transmissible pathogen finds its evolutionary pathway to become a mutant that can cause an epidemic. Many mathematical models of pathogen emergence rely on branching processes. Here, we discuss pathogen emergence using Markov chains, for a more tractable analysis, generalizing previous work by Kendall and Bartlett about disease invasion. We discuss the probability of emergence failure for early epidemics, when the number of infected individuals is small and the number of the susceptible individuals is virtually unlimited. Our formalism addresses both directly transmitted and vector-borne diseases, in the cases where the original pathogen is 1) one step-mutation away from the epidemic strain, and 2) undergoing a long chain of neutral mutations that do not change the epidemiology. We obtain analytic results for the probabilities of emergence failure and two features transcending the transmission mechanism. First, the reproduction number of the original pathogen is determinant for the probability of pathogen emergence, more important than the mutation rate or the transmissibility of the emerged pathogen. Second, the probability of mutation within infected individuals must be sufficiently high for the pathogen undergoing neutral mutations to start an epidemic, the mutation threshold depending again on the basic reproduction number of the original pathogen. Finally, we discuss the parameterization of models of pathogen emergence, using SARS-CoV1 as an example of zoonotic emergence and HIV as an example for the emergence of drug resistance. We also discuss assumptions of our models and implications for epidemiology.

The diverse liver viromes of Australian geckos and skinks are dominated by hepaciviruses and picornaviruses and reflect host taxonomy and habitat

Lizards have diverse ecologies and evolutionary histories, and represent a promising group to explore how hosts shape virome structure and virus evolution. Yet, little is known about the viromes of these animals. In Australia, squamates (lizards and snakes) comprise the most diverse order of vertebrates, and Australia hosts the highest diversity of lizards globally, with the greatest breadth of habitat use. We used meta-transcriptomic sequencing to determine the virome of nine co-distributed, tropical lizard species from three taxonomic families in Australia and analyzed these data to identify host traits associated with viral abundance and diversity. We show that lizards carry a large diversity of viruses, identifying more than thirty novel, highly divergent vertebrate-associated viruses. These viruses were from nine viral families, including several that contain well known pathogens, such as the Flaviviridae, Picornaviridae, Bornaviridae, Iridoviridae, and Rhabdoviridae. Members of the Flaviviridae were particularly abundant across species sampled here, largely belonging to the genus Hepacivirus: fourteen novel hepaciviruses were identified, broadening the known diversity of this group and better defining its evolution by uncovering new reptilian clades. The evolutionary histories of the viruses studied here frequently aligned with the biogeographic and phylogenetic histories of the hosts, indicating that exogenous viruses may help infer host evolutionary history if sampling is strategic and sampling density high enough. Notably, analysis of alpha and beta diversity revealed that virome composition and richness in the animals sampled here was shaped by host taxonomy and habitat. In sum, we identified a diverse range of reptile viruses that broadly contributes to our understanding of virus-host ecology and evolution.

A chromosome-level genome assembly of an avivorous bat species (Nyctalus aviator)

Currently, three carnivorous bat species, namely Ia io, Nyctalus lasiopterus, and Nyctalus aviator, are known to actively prey on seasonal migratory birds (hereinafter referred to as "avivorous bats"). However, the absence of reference genomes impedes a thorough comprehension of the molecular adaptations of avivorous bat species. Herein, we present the high-quality chromosome-scale reference genome of N. aviator based on PacBio subreads, DNBSEQ short-reads and Hi-C sequencing data. The genome assembly size of N. aviator is 1.77 Gb, with a scaffold N50 of 102 Mb, of which 99.8% assembly was anchored into 21 pseudo-chromosomes. After masking 635.1 Mb repetitive sequences, a total of 19,412 protein-coding genes were identified, of which 99.3% were functionally annotated. The genome assembly and gene prediction reached 96.1% and 96.1% completeness of Benchmarking Universal Single-Copy Orthologs (BUSCO), respectively. This chromosome-level reference genome of N. aviator fills a gap in the existing information on the genomes of carnivorous bats, especially avivorous ones, and will be valuable for mechanism of adaptations to dietary niche expansion in bat species.

IRF7 from the black flying fox induces a STAT1-independent ISG response in unstimulated cell lines that protects against diverse RNA viruses

Bats are considered unique in their ability to harbor large numbers of viruses and serve as reservoirs for zoonotic viruses that have the potential to spill over into humans. However, these animals appear relatively resistant to the pathogenic effects of many viruses. Mounting evidence suggests that bats may tolerate viral infections due to unique immune features. These include evolutionary innovations in inflammatory pathways and in the molecules involved in viral sensing, interferon induction, and downstream interferon-induced antiviral effectors. We sought to determine whether interferon-stimulated genes (ISGs) from the black flying fox ( Pteropus alecto ) encoded proteins with unique antiviral activity relative to their human orthologs. Accordingly, we compared the antiviral activity of over 50 ISG human-bat ortholog pairs to identify differences in individual effector functions. We identified IRF7 from Pteropus alecto (Pa.IRF7) as a potent and broad-acting antiviral molecule that provides robust antiviral protection without prior activation. We show that Pa.IRF7 uniquely induces a subset of protective ISGs independent of canonical IFN signaling, which leads to protection from alphaviruses, a flavivirus, a rhabdovirus, and a paramyxovirus. In uninfected cells, Pa.IRF7 partially localizes to the nucleus and can directly bind interferon-sensitive regulatory elements (ISREs). Compared to human IRF7, Pa.IRF7 also has additional serines in its C terminal domain that contribute to antiviral activity and may serve as unique phosphorylation hubs for activation. These properties constitute major differences between bat and human IRF7 that offer additional insight into the potential uniqueness of the black flying fox immune system.

Genomic characterization of a novel Hepatovirus identified in Maranhão state, Brazil

Bats are efficient reservoirs of a number of viruses with zoonotic potential, and are involved directly in the transmission cycle of many zoonoses. In the present study, which is part of a larger project that is documenting the viromes of the bat species found in the Mid-North states of Maranhão and Piauí, we analyzed 16 pooled samples obtained from four species of bat of the genus Artibeus-Artibeus obscurus, Artibeus cinereus, Artibeus lituratus and Artibeus planirostris. We describe and identify a Hepatovirus, denominated Hepatovirus H isolate sotense, which was found in a pool of internal organs (liver and lungs) extracted from a specimen of A. planirostris, a frugivorous bat, collected in the Cerrado biome of Maranhão state. This material was analyzed using new generation sequencing, which produced a contig of 7390 nucleotides and presented a degree of identity with a number of existing Hepatovirus sequences available for bats (amino acid identity of 61.5% with Bat hepatovirus C of Miniopterus cf. manavi, 66.6% with Bat hepatovirus G of Coleura afra, 67.4% with Hepatovirus G2 of Rhinolophus landeri, and 75.3% with Hepatovirus H2 of Rhinolophus landeri). The analysis of the functional domains of this contig confirmed a pattern consistent with the characteristics of the genus Hepatovirus (Picornaviridae). In the phylogenetic tree with several other Hepatovirus species, this genome also grouped in a monophyletic clade with Hepatovirus H (HepV-H1; HepV-H2, and HepV-H3) albeit on an external branch, which suggests that it may be a distinct genotype within this species. This is the first isolate of Hepatovirus H identified in bats from South America, and represents an important discovery, given that most studies of viruses associated with bats in the state of Maranhão have focused on the family Rhabdoviridae.

Bat species assemblage predicts coronavirus prevalence

Anthropogenic disturbances and the subsequent loss of biodiversity are altering species abundances and communities. Since species vary in their pathogen competence, spatio-temporal changes in host assemblages may lead to changes in disease dynamics. We explore how longitudinal changes in bat species assemblages affect the disease dynamics of coronaviruses (CoVs) in more than 2300 cave-dwelling bats captured over two years from five caves in Ghana. This reveals uneven CoV infection patterns between closely related species, with the alpha-CoV 229E-like and SARS-related beta-CoV 2b emerging as multi-host pathogens. Prevalence and infection likelihood for both phylogenetically distinct CoVs is influenced by the abundance of competent species and naïve subadults. Broadly, bat species vary in CoV competence, and highly competent species are more common in less diverse communities, leading to increased CoV prevalence in less diverse bat assemblages. In line with the One Health framework, our work supports the notion that biodiversity conservation may be the most proactive measure to prevent the spread of pathogens with zoonotic potential.

Building a pathway to One Health surveillance and response in Asian countries

To detect and respond to emerging diseases more effectively, an integrated surveillance strategy needs to be applied to both human and animal health. Current programs in Asian countries operate separately for the two sectors and are principally concerned with detection of events that represent a short-term disease threat. It is not realistic to either invest only in efforts to detect emerging diseases, or to rely solely on event-based surveillance. A comprehensive strategy is needed, concurrently investigating and managing endemic zoonoses, studying evolving diseases which change their character and importance due to influences such as demographic and climatic change, and enhancing understanding of factors which are likely to influence the emergence of new pathogens. This requires utilisation of additional investigation tools that have become available in recent years but are not yet being used to full effect. As yet there is no fully formed blueprint that can be applied in Asian countries. Hence a three-step pathway is proposed to move towards the goal of comprehensive One Health disease surveillance and response.

Potential zoonotic spillover at the human-animal interface: A mini-review

Wildlife markets and wet wildlife markets, a type of human-animal interface, are commonly trading centers for wild-caught and captive-exotic animals as well as their products. These markets provide an ideal environment for spillovers of zoonotic and emerging infectious diseases (EIDs). These conditions may raise serious concerns, particularly in relation to wildlife species that frequently interact with humans and domestic animals. EIDs pose a significant risk to humans, ecosystems, and public health, as demonstrated by the current COVID-19 pandemic, and other previous outbreaks, including the highly pathogenic avian influenza H5N1. Even though it seems appears impossible to eliminate EIDs, we may still be able to minimalize the risks and take several measures to prevent new EIDs originated from animals. The aim of this study was to review several types of human-animal interfaces with a high risk of zoonotic spillover, infectious agents, and animal hosts or reservoirs. Identifying those factors will support the development of interventions and effective disease control in human-animal interface settings.

Virome of Australia's most endangered parrot in captivity evidenced of harboring hitherto unknown viruses

IMPORTANCE

The impact of circulating viruses on the critically endangered, orange-bellied parrot (OBP) population can be devastating. The OBP already faces numerous threats to its survival in the wild, including habitat loss, predation, and small population impacts. Conservation of the wild OBP population is heavily reliant on supplementation using OBPs from a managed captive breeding program. These birds may act as a source for introduction of a novel disease agent to the wild population that may affect survival and reproduction. It is, therefore, essential to monitor and assess the health of OBPs and take appropriate measures to prevent and control the spread of viral infections. This requires knowledge of the existing virome to identify novel and emerging viruses and support development of appropriate measures to manage associated risk. By monitoring and protecting these animals from emerging viral diseases, we can help ensure their ongoing survival and preserve the biodiversity of our planet.

A protocol and a data-based prediction to investigate virus spillover at the wildlife interface in human-dominated and protected habitats in Thailand: The Spillover Interface project

The Spillover Interface Project aims at assessing the encounter of wildlife, domestic animals, and humans along a landscape gradient from a protected area to a residential community, through areas of reforestation and agricultural land. Here, we present the protocols of the project that combine virus screening in humans, bats, rodents and dogs with camera trapping, land-use characterization, and network analyses. The project is taking place in the sub-district of Saen Thong (Nan Province, Thailand) in collaboration with local communities, the District Public Health Office, and Nanthaburi National Park. To formulate a predictive hypothesis for the Spillover Interface Project, we assess the wildlife diversity and their viral diversity that could be observed in Saen Thong through a data science analysis approach. Potential mammalian species are estimated using data from the International Union for Conservation of Nature (IUCN) and their associated viral diversity from a published open database. A network analysis approach is used to represent and quantify the transmission of the potential viruses hosted by the mammals present in Saen Thong, according to the IUCN. A total of 57 viruses are expected to be found and shared between 43 host species, including the domestic dog and the human species. By following the protocols presented here, the Spillover Interface Project will collect the data and samples needed to test this data-driven prediction.

Genomic and biological variation in bat IFNs: An antiviral treatment approach

Bat-borne viruses have attracted considerable research, especially in relation to the Covid-19 pandemic. Although bats can carry multiple zoonotic viruses that are lethal to many mammalian species, they appear to be asymptomatic to viral infection despite the high viral loads contained in their bodies. There are several differences between bats and other mammals. One of the major differences between bats and other mammals is the bats' ability to fly, which is believed to have induced evolutionary changes. It may have also favoured them as suitable hosts for viruses. This is related to their tolerance to viral infection. Innate immunity is the first line of defence against viral infection, but bats have metamorphosed the type of responses induced by innate immunity factors such as interferons. The expression patterns of interferons differ, as do those of interferon-related genes such as interferon regulatory factors and interferon-stimulated genes that contribute to the antiviral response of infected cells. In addition, the signalling pathways related to viral infection and immune responses have been subject to evolutionary changes, including mutations compared to their homologues in other mammals and gene selection. This article discusses the differences in the interferon-mediated antiviral response in bats compared to that of other mammals and how these differences are correlated to viral tolerance in bats. The effect of bat interferons related genes on human antiviral response against bat-borne viruses is also discussed.

Climate match is key to predict range expansion of the world's worst invasive terrestrial vertebrates

Understanding the determinants of the range expansion of invasive alien species is crucial for developing effective prevention and control strategies. Nevertheless, we still lack a global picture of the potential factors influencing the invaded range expansion across taxonomic groups, especially for the world's worst invaders with high ecological and economic impacts. Here, by extensively collecting data on 363 distributional ranges of 19 of world's worst invasive terrestrial vertebrates across 135 invaded administrative jurisdictions, we observed remarkable variations in the range expansion across species and taxonomic groups. After controlling for taxonomic and geographic pseudoreplicates, model averaging analyses based on generalized additive mixed-effect models showed that species in invaded regions having climates more similar to those of their native ranges tended to undergo a larger range expansion. In addition, as proxies of propagule pressure and human-assisted transportation, the number of introduction events and the road network density were also important predictors facilitating the range expansion. Further variance partitioning analyses validated the predominant role of climate match in explaining the range expansion. Our study demonstrated that regions with similar climates to their native ranges could still be prioritized to prevent the spread of invasive species under the sustained global change.

Evolutionary Analysis of a Parrot Bornavirus 2 Detected in a Sulphur-Crested Cockatoo (Cacatua galerita) Suggests a South American Ancestor

Parrot bornavirus (PaBV) is an RNA virus that causes Proventricular Dilatation Disease (PDD), neurological disorders, and death in Psittaciformes. Its diversity in South America is poorly known. We examined a Cacatua galerita presenting neuropathies, PDD, and oculopathies as the main signs. We detected PaBV through reverse transcription polymerase chain reaction (RT-PCR) and partial sequencing of the nucleoprotein (N) and matrix (M) genes. Maximum likelihood and Bayesian phylogenetic inferences classified it as PaBV-2. The nucleotide identity of the sequenced strain ranged from 88.3% to 90.3% against genotype PaBV-2 and from 80.2% to 84.4% against other genotypes. Selective pressure analysis detected signs of episodic diversifying selection in both the N and M genes. No recombination events were detected. Phylodynamic analysis estimated the time to the most recent common ancestor (TMRCA) as the year 1758 for genotype PaBV-2 and the year 1049 for the Orthobornavirus alphapsittaciforme species. Substitution rates were estimated at 2.73 × 10-4 and 4.08 × 10-4 substitutions per year per site for N and M, respectively. The analysis of population dynamics showed a progressive decline in the effective population size during the last century. Timescale phylogeographic analysis revealed a potential South American ancestor as the origin of genotypes 1, 2, and 8. These results contribute to our knowledge of the evolutionary origin, diversity, and dynamics of PaBVs in South America and the world. Additionally, it highlights the importance of further studies in captive Psittaciformes and the potential impact on endangered wild birds.

The coevolutionary mosaic of bat betacoronavirus emergence risk

Pathogen evolution is one of the least predictable components of disease emergence, particularly in nature. Here, building on principles established by the geographic mosaic theory of coevolution, we develop a quantitative, spatially explicit framework for mapping the evolutionary risk of viral emergence. Driven by interest in diseases like Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS), and Coronavirus disease 2019 (COVID-19), we examine the global biogeography of bat-origin betacoronaviruses, and find that coevolutionary principles suggest geographies of risk that are distinct from the hotspots and coldspots of host richness. Further, our framework helps explain patterns like a unique pool of merbecoviruses in the Neotropics, a recently discovered lineage of divergent nobecoviruses in Madagascar, and-most importantly-hotspots of diversification in southeast Asia, sub-Saharan Africa, and the Middle East that correspond to the site of previous zoonotic emergence events. Our framework may help identify hotspots of future risk that have also been previously overlooked, like West Africa and the Indian subcontinent, and may more broadly help researchers understand how host ecology shapes the evolution and diversity of pandemic threats.

Bat-associated microbes: Opportunities and perils, an overview

The potential biotechnological uses of bat-associated bacteria are discussed briefly, indicating avenues for biotechnological applications of bat-associated microbes. The uniqueness of bats in terms of their lifestyle, genomes and molecular immunology may predispose bats to act as disease reservoirs. Molecular phylogenetic analysis has shown several instances of bats harbouring the ancestral lineages of bacterial (Bartonella), protozoal (Plasmodium, Trypanosoma cruzi) and viral (SARS-CoV2) pathogens infecting humans. Along with the transmission of viruses from bats, we also discuss the potential roles of bat-associated bacteria, fungi, and protozoan parasites in emerging diseases. Current evidence suggests that environmental changes and interactions between wildlife, livestock, and humans contribute to the spill-over of infectious agents from bats to other hosts. Domestic animals including livestock may act as intermediate amplifying hosts for bat-origin pathogens to transmit to humans. An increasing number of studies investigating bat pathogen diversity and infection dynamics have been published. However, whether or how these infectious agents are transmitted both within bat populations and to other hosts, including humans, often remains unknown. Metagenomic approaches are uncovering the dynamics and distribution of potential pathogens in bat microbiomes, which might improve the understanding of disease emergence and transmission. Here, we summarize the current knowledge on bat zoonoses of public health concern and flag the gaps in the knowledge to enable further research and allocation of resources for tackling future outbreaks.

RNA virus diversity in rodents

Many zoonotic disease emergencies are associated with RNA viruses in rodents that substantially impact public health. With the widespread application of meta-genomics and meta-transcriptomics for virus discovery over the last decade, viral sequences deposited in public databases have expanded rapidly, and the number of novel viruses discovered in rodents has increased. As important reservoirs of zoonotic viruses, rodents have attracted increasing attention for the risk of potential spillover of rodent-borne viruses. However, knowledge of rodent viral diversity and the major factors contributing to the risk of zoonotic epidemic outbreaks remains limited. Therefore, this study analyzes the diversity and composition of rodent RNA viruses using virus records from the Database of Rodent-associated Viruses (DRodVir/ZOVER), which covers the published literatures and records in GenBank database, reviews the main rodent RNA virus-induced human infectious diseases, and discusses potential challenges in this field.

Oxidative damage varies in response to bacterial, fungal and viral antigen challenges in bats

The immune system plays an important role in defending against pathogens and regulating physiological homeostasis, but the strength of the immune responses depends on the type of pathogen. The immune system of bats shows a high variability in responsiveness towards various pathogens; they can safely harbor certain pathogens that are highly lethal to other mammals. Oxidative stress may act as a pathophysiological cellular mechanism mediating the immunological function of bats because of its potentially detrimental effects on physiological homeostasis, fertility and longevity. By experimentally exposing greater mouse-eared bats (Myotis myotis) to three antigens, it was previously shown that animals reacted immunologically most strongly to bacterial and viral antigens, but not to fungal ones. As a follow up, in this study we observed that both bacterial and fungal antigens induced a significant increase of plasma oxidative damage, whereas viral antigens did not cause any increase of plasma oxidative damage at all albeit the mild immune response. Thus, experimental bats were able to avoid oxidative stress only in the face of a viral antigen, possibly by dampening inflammatory signalling. Bats may be able to handle viral infections and live well beyond expectations by reducing the detrimental effects of molecular oxidation.

A new multiplexed magnetic capture-Droplet digital PCR tool for monitoring wildlife population health and pathogen surveillance

Anthropogenic stressors are exacerbating the emergence and spread of pathogens worldwide. In regions like the Arctic, where ecosystems are particularly susceptible, marked changes are predicted in regional diversity, intensity, and patterns of infectious diseases. To understand such rapidly changing host-pathogen dynamics and mitigate the impacts of novel pathogens, we need sensitive disease surveillance tools. We developed and validated a novel multiplexed, magnetic capture, and ddPCR tool for the surveillance of multiple pathogens in polar bears, a sentinel species that is considered susceptible to climate change and other stressors with a pan-Arctic distribution. Through sequence-specific magnetic capture, we concentrated five target template sequences from three zoonotic bacteria (Erysipelothrix rhusiopathiae, Francisella tularensis, and Mycobacterium tuberculosis complex) and two parasitic (Toxoplasma gondii and Trichinella spp.) pathogens from large quantities (<100 g) of host tissue. We then designed and validated two multiplexed probe-based ddPCR assays for the amplification and detection of the low-concentration target DNA. Validations used 48 polar bear tissues (muscle and liver). We detected 14, 1, 3, 4, and 22 tissue positives for E. rhusiopathiae, F. tularensis, M. tuberculosis complex, T. gondii, and Trichinella spp., respectively. These multiplexed assays offer a rapid, specific tool for quantifying and monitoring the changing geographical and host distributions of pathogens relevant to human and animal health.

Selective, broad-spectrum antiviral photodynamic disinfection with dicationic imidazolyl chlorin photosensitizers

The COVID-19 pandemic exposes our vulnerability to viruses that acquire the ability to infect our cells. Classical disinfection methods are limited by toxicity. Existing medicines performed poorly against SARS-CoV-2 because of their specificity to targets in different organisms. We address the challenge of mitigating known and prospective viral infections with a new photosensitizer for antimicrobial photodynamic therapy (aPDT). Photodynamic inactivation is based on local oxidative stress, which is particularly damaging to enveloped viruses. We synthesized a cationic imidazolyl chlorin that reduced by > 99.999% of the percentage inhibition of amplification of SARS-CoV-2 collected from patients at 0.2 µM concentration and 4 J cm-2. Similar results were obtained in the prevention of infection of human ACE2-expressing HEK293T cells by a pseudotyped lentiviral vector exhibiting the S protein of SARS-CoV-2 at its surface. No toxicity to human epidermal keratinocytes (HaCaT) cells was found under similar conditions. aPDT with this chlorin offers fast and safe broad-spectrum photodisinfection and can be repeated with low risk of resistance.

Viral genomic features predict orthopoxvirus reservoir hosts

Orthopoxviruses (OPVs), including the causative agents of smallpox and mpox have led to devastating outbreaks in human populations worldwide. However, the discontinuation of smallpox vaccination, which also provides cross-protection against related OPVs, has diminished global immunity to OPVs more broadly. We apply machine learning models incorporating both host ecological and viral genomic features to predict likely reservoirs of OPVs. We demonstrate that incorporating viral genomic features in addition to host ecological traits enhanced the accuracy of potential OPV host predictions, highlighting the importance of host-virus molecular interactions in predicting potential host species. We identify hotspots for geographic regions rich with potential OPV hosts in parts of southeast Asia, equatorial Africa, and the Amazon, revealing high overlap between regions predicted to have a high number of potential OPV host species and those with the lowest smallpox vaccination coverage, indicating a heightened risk for the emergence or establishment of zoonotic OPVs. Our findings can be used to target wildlife surveillance, particularly related to concerns about mpox establishment beyond its historical range.

Host traits shape virome composition and virus transmission in wild small mammals

Bats, rodents, and shrews are the most important animal sources of human infectious diseases. However, the evolution and transmission of viruses among them remain largely unexplored. Through the meta-transcriptomic sequencing of internal organ and fecal samples from 2,443 wild bats, rodents, and shrews sampled from four Chinese habitats, we identified 669 viruses, including 534 novel viruses, thereby greatly expanding the mammalian virome. Our analysis revealed high levels of phylogenetic diversity, identified cross-species virus transmission events, elucidated virus origins, and identified cases of invertebrate viruses in mammalian hosts. Host order and sample size were the most important factors impacting virome composition and patterns of virus spillover. Shrews harbored a high richness of viruses, including many invertebrate-associated viruses with multi-organ distributions, whereas rodents carried viruses with a greater capacity for host jumping. These data highlight the remarkable diversity of mammalian viruses in local habitats and their ability to emerge in new hosts.

Gammaretroviruses, novel viruses and pathogenic bacteria in Australian bats with neurological signs, pneumonia and skin lesions

More than 70 bat species are found in mainland Australia. While most studies of bat viromes focus on sampling seemingly healthy individuals, little is known about the viruses and bacteria associated with diseased bats. We performed traditional diagnostic techniques and metatranscriptomic sequencing on tissue samples from 43 Australian bats, comprising three flying fox (Pteropodidae) and two microbat species experiencing a range of disease syndromes, including mass mortality, neurological signs, pneumonia and skin lesions. Of note, we identified the recently discovered Hervey pteropid gammaretrovirus in a bat with lymphoid leukemia, with evidence of replication consistent with an exogenous virus. The possible association of Hervey pteropid gammaretrovirus with lymphoid leukemia clearly merits additional investigation. One novel picornavirus and at least three new astroviruses and bat pegiviruses were also identified in a variety of tissue types, as well as a number of likely bacterial pathogens or opportunistic infections, most notably Pseudomonas aeruginosa.

Genes, inflammatory response, tolerance, and resistance to virus infections in migratory birds, bats, and rodents

Normally, the host immunological response to viral infection is coordinated to restore homeostasis and protect the individual from possible tissue damage. The two major approaches are adopted by the host to deal with the pathogen: resistance or tolerance. The nature of the responses often differs between species and between individuals of the same species. Resistance includes innate and adaptive immune responses to control virus replication. Disease tolerance relies on the immune response allowing the coexistence of infections in the host with minimal or no clinical signs, while maintaining sufficient viral replication for transmission. Here, we compared the virome of bats, rodents and migratory birds and the molecular mechanisms underlying symptomatic and asymptomatic disease progression. We also explore the influence of the host physiology and environmental influences on RNA virus expression and how it impacts on the whole brain transcriptome of seemingly healthy semipalmated sandpiper (Calidris pusilla) and spotted sandpiper (Actitis macularius). Three time points throughout the year were selected to understand the importance of longitudinal surveys in the characterization of the virome. We finally revisited evidence that upstream and downstream regulation of the inflammatory response is, respectively, associated with resistance and tolerance to viral infections.

Comparison of antiviral responses in two bat species reveals conserved and divergent innate immune pathways

Bats host a range of disease-causing viruses without displaying clinical symptoms. The mechanisms behind this are a continuous source of interest. Here, we studied the antiviral response in the Egyptian fruit bat and Kuhl's pipistrelle, representing two subordinal clades. We profiled the antiviral response in fibroblasts using RNA sequencing and compared bat with primate and rodent responses. Both bats upregulate similar genes; however, a subset of these genes is transcriptionally divergent between them. These divergent genes also evolve rapidly in sequence, have specific promoter architectures, and are associated with programs underlying tolerance and resistance. Finally, we characterized antiviral genes that expanded in bats, with duplicates diverging in sequence and expression. Our study reveals a largely conserved antiviral program across bats and points to a set of genes that rapidly evolve through multiple mechanisms. These can contribute to bat adaptation to viral infection and provide directions to understanding the mechanisms behind it.

Investigating and combatting the key drivers of viral zoonoses in Africa: an analysis of eight epidemics

Investigating the interplay of factors that result in a viral zoonotic outbreak is difficult, though it is increasingly important. As anthropogenic influences shift the delicate balance of ecosystems, new zoonoses emerge in humans. Sub-Saharan Africa is a notable hotspot for zoonotic disease due to abundant competent mammalian reservoir hosts. Furthermore, poverty, corruption, and an overreliance on natural resources play considerable roles in depleting biological resources, exacerbating the population's susceptibility. Unsurprisingly, viral zoonoses have emerged in Africa, including HIV/AIDS, Ebola, Avian influenza, Lassa fever, Zika, and Monkeypox. These diseases are among the principal causes of death in endemic areas. Though typically distinct in their manifestations, viral zoonoses are connected by underlying, definitive factors. This review summarises vital findings on viral zoonoses in Africa using nine notable case studies as a benchmark for future studies. We discuss the importance of ecological recuperation and protection as a central strategy to control zoonotic diseases. Emphasis was made on moderating key drivers of zoonotic diseases to forestall future pandemics. This is in conjunction with attempts to redirect efforts from reactive to pre-emptive through a multidisciplinary "one health" approach.

Variations in small-scale movements of, Rousettus aegyptiacus, a Marburg virus reservoir across a seasonal gradient

BACKGROUND

Bats are increasingly being recognized as important hosts for viruses, some of which are zoonotic and carry the potential for spillover within human and livestock populations. Biosurveillance studies focused on assessing the risk of pathogen transmission, however, have largely focused on the virological component and have not always considered the ecological implications of different species as viral hosts. The movements of known viral hosts are an important component for disease risk assessments as they can potentially identify regions of higher risk of contact and spillover. As such, this study aimed to synthesize data from both virological and ecological fields to provide a more holistic assessment of the risk of pathogen transmission from bats to people.

RESULTS

Using radiotelemetry, we tracked the small-scale movements of Rousettus aegyptiacus, a species of bat known to host Marburg virus and other viruses with zoonotic potential, in a rural settlement in Limpopo Province, South Africa. The tracked bats exhibited seasonal variations in their movement patterns including variable usage of residential areas which could translate to contact between bats and humans and may facilitate spillover. We identified a trend for increased usage of residential areas during the winter months with July specifically experiencing the highest levels of bat activity within residential areas. July has previously been identified as a key period for increased spillover risk for viruses associated with R. aegyptiacus from this colony and paired with the increased activity levels, illustrates the risk for spillover to human populations.

CONCLUSION

This study emphasizes the importance of incorporating ecological data such as movement patterns with virological data to provide a better understanding of the risk of pathogen spillover and transmission.

Co-circulation and co-infection of hantaviruses and Wenzhou mammarenavirus in small mammals and humans in Jiangxi, China

Both Orthohantaviruses (HV) and Whenzhou Mammarenaviruses (WENV) are rodents borne viruses, allowing them to spread simultaneously in the same area and infect humans. To explore the potential threat of HV and WENV to public health safety, an environmental and laboratory investigation was conducted in 2020-2021, in Jiangxi province, China. A total of 461 small mammals of 7 species and paired sera from 43 suspected HFRS cases were collected from Jiangxi Province, China. Viral genomic RNA and specific antibodies against HV and WENV were detected to evaluate the epidemic situation of the two viruses. Hantaan virus (HTNV), seoul virus (SEOV) and WENV RNA were detected in the lungs of the captured mammals, which resulted 4.1% and 7.4% of HV and WENV RNA positive respectively. Co-infections of WENV and SEOV were detected from Rattus norvegicus, Mus musculus and Rattus flavipectus with an overall co-infection rate of 0.65%. The detection rates of antibodies in the blood against HV and WENV were 11.9% (55/461), and 13.2% (61/461) respectively. The prevalence of viral infection and viral genetic characters varied among the selected areas. In the paired sera of 43 suspected HFRS cases, 38 were with HV infection, 11 were with WENV IgG, and 7 with a 4-fold or more of WENV IgG titer elevation. These results revealed the fact of the co-circulating and coinfection of HV and WENV in the same area at the same time, which might impact on public health safety.

Individual bat virome analysis reveals co-infection and spillover among bats and virus zoonotic potential

Bats are reservoir hosts for many zoonotic viruses. Despite this, relatively little is known about the diversity and abundance of viruses within individual bats, and hence the frequency of virus co-infection and spillover among them. We characterize the mammal-associated viruses in 149 individual bats sampled from Yunnan province, China, using an unbiased meta-transcriptomics approach. This reveals a high frequency of virus co-infection (simultaneous infection of bat individuals by multiple viral species) and spillover among the animals studied, which may in turn facilitate virus recombination and reassortment. Of note, we identify five viral species that are likely to be pathogenic to humans or livestock, based on phylogenetic relatedness to known pathogens or in vitro receptor binding assays. This includes a novel recombinant SARS-like coronavirus that is closely related to both SARS-CoV and SARS-CoV-2. In vitro assays indicate that this recombinant virus can utilize the human ACE2 receptor such that it is likely to be of increased emergence risk. Our study highlights the common occurrence of co-infection and spillover of bat viruses and their implications for virus emergence.

The structure of songbird MHC class I reveals antigen binding that is flexible at the N-terminus and static at the C-terminus

Long-distance migratory animals such as birds and bats have evolved to withstand selection imposed by pathogens across the globe, and pathogen richness is known to be particularly high in tropical regions. Immune genes, so-called Major Histocompatibility Complex (MHC) genes, are highly duplicated in songbirds compared to other vertebrates, and this high MHC diversity has been hypothesised to result in a unique adaptive immunity. To understand the rationale behind the evolution of the high MHC genetic diversity in songbirds, we determined the structural properties of an MHC class I protein, Acar3, from a long-distance migratory songbird, the great reed warbler Acrocephalus arundinaceus (in short: Acar). The structure of Acar3 was studied in complex with pathogen-derived antigens and shows an overall antigen presentation similar to human MHC class I. However, the peptides bound to Acar3 display an unusual conformation: Whereas the N-terminal ends of the peptides display enhanced flexibility, the conformation of their C-terminal halves is rather static. This uncommon peptide-binding mode in Acar3 is facilitated by a central Arg residue within the peptide-binding groove that fixes the backbone of the peptide at its central position, and potentially permits successful interactions between MHC class I and innate immune receptors. Our study highlights the importance of investigating the immune system of wild animals, such as birds and bats, to uncover unique immune mechanisms which may neither exist in humans nor in model organisms.

Foraging and mating behaviors of Hypsignathus monstrosus at the bat-human interface in a central African rainforest

Studying wildlife space use in human-modified environments contributes to characterize wildlife-human interactions to assess potential risks of zoonotic-pathogens transmission, and to pinpoint conservation issues. In central African rainforests with human dwelling and activities, we conducted a telemetry study on a group of males of Hypsignathus monstrosus, a lek-mating fruit bat identified as a potential maintenance host for Ebola virus. During a lekking season in 2020, we investigated the foraging-habitat selection and the individual nighttime space use during both mating and foraging activities close to villages and their surrounding agricultural landscape. At night, marked individuals strongly selected agricultural lands and more generally areas near watercourses to forage, where they spent more time compared to forest ones. Furthermore, the probability and duration of the presence of bats in the lek during nighttime decreased with the distance to their roost site but remained relatively high within a 10 km radius. Individuals adjusted foraging behaviors according to mating activity by reducing both the overall time spent in foraging areas and the number of forest areas used to forage when they spent more time in the lek. Finally, the probability of a bat revisiting a foraging area in the following 48 hours increased with the previous time spent in that foraging area. These behaviors occurring close to or in human-modified habitats can trigger direct and indirect bat-human contacts, which could thus facilitate pathogen transmission such as Ebola virus.

Temporal Variations in the Gut Microbiota of the Globally Endangered Sichuan Partridge (Arborophila rufipectus): Implications for Adaptation to Seasonal Dietary Change and Conservation

Host-associated microbiotas are known to influence host health by aiding digestion, metabolism, nutrition, physiology, immune function, and pathogen resistance. Although an increasing number of studies have investigated the avian microbiome, there is a lack of research on the gut microbiotas of wild birds, especially endangered pheasants. Owing to the difficulty of characterizing the dynamics of dietary composition, especially in omnivores, how the gut microbiotas of birds respond to seasonal dietary changes remains poorly understood. The Sichuan partridge (Arborophila rufipectus) is an endangered pheasant species with a small population endemic to the mountains of southwest China. Here, 16S rRNA sequencing and Tax4Fun were used to characterize and compare community structure and functions of the gut microbiota in the Sichuan partridges across three critical periods of their annual life cycle (breeding, postbreeding wandering, and overwintering). We found that the microbial communities were dominated by Firmicutes, Proteobacteria, Actinobacteria, and Cyanobacteria throughout the year. Diversity of the gut microbiotas was highest during postbreeding wandering and lowest during the overwintering periods. Seasonal dietary changes and reassembly of the gut microbial community occurred consistently. Composition, diversity, and functions of the gut microbiota exhibited diet-associated variations, which might facilitate host adaptation to diverse diets in response to environmental shifts. Moreover, 28 potential pathogenic genera were detected, and their composition differed significantly between the three periods. Investigation of the wild bird gut microbiota dynamics has enhanced our understanding of diet-microbiota associations over the annual life cycle of birds, aiding in the integrative conservation of this endangered bird. IMPORTANCE Characterizing the gut microbiotas of wild birds across seasons will shed light on their annual life cycle. Due to sampling difficulties and the lack of detailed dietary information, studies on how the gut microbiota adapts to seasonal dietary changes of wild birds are scarce. Based on more detailed dietary composition, we found a seasonal reshaping pattern of the gut microbiota of Sichuan partridges corresponding to their seasonal dietary changes. The variation in diet and gut microbiota potentially facilitated the diversity of dietary niches of this endangered pheasant, revealing a seasonal diet-microbiota association across the three periods of the annual cycle. In addition, identifying a variety of potentially pathogenic bacterial genera aids in managing the health and improving survival of Sichuan partridges. Incorporation of microbiome research in the conservation of endangered species contributes to our comprehensive understanding the diet-host-microbiota relationship in wild birds and refinement of conservation practices.

Higher convergence of human-great ape enteric eukaryotic viromes in central African forest than in a European zoo: a One Health analysis

Human-animal pathogenic transmissions threaten both human and animal health, and the processes catalyzing zoonotic spillover and spillback are complex. Prior field studies offer partial insight into these processes but overlook animal ecologies and human perceptions and practices facilitating human-animal contact. Conducted in Cameroon and a European zoo, this integrative study elucidates these processes, incorporating metagenomic, historical, anthropological and great ape ecological analyses, and real-time evaluation of human-great ape contact types and frequencies. We find more enteric eukaryotic virome sharing between Cameroonian humans and great apes than in the zoo, virome convergence between Cameroonian humans and gorillas, and adenovirus and enterovirus taxa as most frequently shared between Cameroonian humans and great apes. Together with physical contact from hunting, meat handling and fecal exposure, overlapping human cultivation and gorilla pillaging in forest gardens help explain these findings. Our multidisciplinary study identifies environmental co-use as a complementary mechanism for viral sharing.

Surveillance, Isolation, and Genetic Characterization of Bat Herpesviruses in Zambia

Bats are of significant interest as reservoirs for various zoonotic viruses with high diversity. During the past two decades, many herpesviruses have been identified in various bats worldwide by genetic approaches, whereas there have been few reports on the isolation of infectious herpesviruses. Herein, we report the prevalence of herpesvirus infection of bats captured in Zambia and genetic characterization of novel gammaherpesviruses isolated from striped leaf-nosed bats (Macronycteris vittatus). By our PCR screening, herpesvirus DNA polymerase (DPOL) genes were detected in 29.2% (7/24) of Egyptian fruit bats (Rousettus aegyptiacus), 78.1% (82/105) of Macronycteris vittatus, and one Sundevall's roundleaf bat (Hipposideros caffer) in Zambia. Phylogenetic analyses of the detected partial DPOL genes revealed that the Zambian bat herpesviruses were divided into seven betaherpesvirus groups and five gammaherpesvirus groups. Two infectious strains of a novel gammaherpesvirus, tentatively named Macronycteris gammaherpesvirus 1 (MaGHV1), were successfully isolated from Macronycteris vittatus bats, and their complete genomes were sequenced. The genome of MaGHV1 encoded 79 open reading frames, and phylogenic analyses of the DNA polymerase and glycoprotein B demonstrated that MaGHV1 formed an independent lineage sharing a common origin with other bat-derived gammaherpesviruses. Our findings provide new information regarding the genetic diversity of herpesviruses maintained in African bats.

Network embedding unveils the hidden interactions in the mammalian virome

Predicting host-virus interactions is fundamentally a network science problem. We develop a method for bipartite network prediction that combines a recommender system (linear filtering) with an imputation algorithm based on low-rank graph embedding. We test this method by applying it to a global database of mammal-virus interactions and thus show that it makes biologically plausible predictions that are robust to data biases. We find that the mammalian virome is under-characterized anywhere in the world. We suggest that future virus discovery efforts could prioritize the Amazon Basin (for its unique coevolutionary assemblages) and sub-Saharan Africa (for its poorly characterized zoonotic reservoirs). Graph embedding of the imputed network improves predictions of human infection from viral genome features, providing a shortlist of priorities for laboratory studies and surveillance. Overall, our study indicates that the global structure of the mammal-virus network contains a large amount of information that is recoverable, and this provides new insights into fundamental biology and disease emergence.

Discovery of a novel bat lyssavirus in a Long-fingered bat (Myotis capaccinii) from Slovenia

Lyssaviruses are the causative agents of rabies, a zoonotic, fatal disease that is thought to be ancestral to bats. In the last decade, the detection of bat associated lyssaviruses is increasing also in Europe. Within a retrospective bat associated lyssavirus surveillance study a total of 225 dead bats of 21 bat species were collected in Slovenia between 2012 and 2019 and tested by specific real-time RT-PCR method. The first lyssavirus positive sample in bats in Slovenia was detected using the real-time RT-PCR, the fluorescent antibody test, and next generation sequencing, while the rabies tissue culture inoculation test was unsuccessful due to sample degradation and storage conditions. The nearly complete genome of Divača bat lyssavirus from Slovenia consists of 11,871 nucleotides and reflects the characteristic gene organization known for lyssaviruses, encoding the five viral proteins. Phylogenetic analysis of Divača bat lyssavirus revealed that it belongs to phylogroup I lyssaviruses and is most closely related to Kotalahti bat lyssavirus (KBLV) with 87.20% nucleotide and 99.22% amino acid identity. Together with KBLV, Khujand virus, European bat lyssavirus 2, Bakeloh bat lyssavirus, and Aravan virus, Divača bat lyssavirus was detected in the genus Myotis suggesting its key role in the transmission and maintenance of certain lyssaviruses.

An immediate way to lower pandemic risk: (not) seizing the low-hanging fruit (bat)

What is the least that humanity can do to mitigate the risks of future pandemics, to prevent worldwide surges in human deaths, illness, and suffering-and more waves of multitrillion US dollar impacts on the global economy? The issues around our consumption and trading of wildlife are diverse and complex, with many rural communities being dependent on wild meat for their nutritional needs. But bats might be one taxonomic group that can be successfully eliminated from the human diet and other uses, with minimal costs or inconvenience to the vast majority of the 8 billion people on Earth. The order Chiroptera merits genuine respect given all that these species contribute to human food supplies through pollination services provided by the frugivores and to disease risk mitigation delivered by insectivorous species. The global community missed its chance to stop SARS-CoV and SARS-CoV-2 from emerging-how many more times will humanity allow this cycle to repeat? How long will governments ignore the science that is in front of them? It's past time for humans to do the least that can be done. A global taboo is needed whereby humanity agrees to leave bats alone, not fear them or try to chase them away or cull them, but to let them have the habitats they need and live undisturbed by humans.

A species-level trait dataset of bats in Europe and beyond

Knowledge of species' functional traits is essential for understanding biodiversity patterns, predicting the impacts of global environmental changes, and assessing the efficiency of conservation measures. Bats are major components of mammalian diversity and occupy a variety of ecological niches and geographic distributions. However, an extensive compilation of their functional traits and ecological attributes is still missing. Here we present EuroBaTrait 1.0, the most comprehensive and up-to-date trait dataset covering 47 European bat species. The dataset includes data on 118 traits including genetic composition, physiology, morphology, acoustic signature, climatic associations, foraging habitat, roost type, diet, spatial behaviour, life history, pathogens, phenology, and distribution. We compiled the bat trait data obtained from three main sources: (i) a systematic literature and dataset search, (ii) unpublished data from European bat experts, and (iii) observations from large-scale monitoring programs. EuroBaTrait is designed to provide an important data source for comparative and trait-based analyses at the species or community level. The dataset also exposes knowledge gaps in species, geographic and trait coverage, highlighting priorities for future data collection.

Organophosphorus Poisoning: Acute Respiratory Distress Syndrome (ARDS) and Cardiac Failure as Cause of Death in Hospitalized Patients

Industrial production of food for animals and humans needs increasing amounts of pesticides, especially of organophosphates, which are now easily available worldwide. More than 3 million cases of acute severe poisoning are estimated to occur worldwide every year, and even more cases remain unreported, while 200,000-350,000 incidentally or intentionally poisoned people die every year. Diagnostic and therapeutic procedures in organophosphate poisoning have, however, remained unchanged. In addition to several neurologic symptoms (miosis, fasciculations), hypersecretion of salivary, bronchial, and sweat glands, vomiting, diarrhea, and loss of urine rapidly induce dehydration, hypovolemia, loss of conscience and respiratory distress. Within hours, signs of acidosis due to systemic hypoxia can be observed at first laboratory investigation after hospitalization. While determination of serum-cholinesterase does not have any diagnostic value, it has been established that hypoalbuminemia alone or accompanied by an increase in creatinine, lactate, or C-reactive protein serum levels has negative prognostic value. Increased serum levels of C-reactive protein are a sign of systemic ischemia. Protective mechanical ventilation should be avoided, if possible. In fact, acute respiratory distress syndrome characterized by congestion and increased weight of the lung, accompanied by heart failure, may become the cause of death. As the excess of acetylcholine at the neuronal level can persist for weeks until enough newly, locally synthesized acetylcholinesterase becomes available (the value of oximes in reducing this time is still under debate), after atropine administration, intravenous albumin and fluid infusion should be the first therapeutic interventions to reestablish normal blood volume and normal tissue oxygenation, avoiding death by cardiac arrest.

The pathogenesis of zoonotic viral infections: Lessons learned by studying reservoir hosts

Zoonotic viral infections that cause severe disease or even death in some people may be asymptomatic or mild in reservoir hosts. Comparison of the pathogenesis of these two host categories may potentially explain the difference in disease. However, infections in reservoir hosts are often neglected. Therefore, we compared the pathogenesis of rabies virus, macacine alphaherpesvirus, West Nile virus, Puumala orthohantavirus, monkeypox virus, Lassa mammarenavirus, H5N1 highly pathogenic avian influenza, Marburg virus, Nipah virus, Middle East respiratory syndrome, and simian/human immunodeficiency viruses in both humans and reservoir hosts. We showed that most aspects of the pathogeneses were remarkably similar. The remaining differences lead to the identification of tipping points in the pathogeneses that are important for explaining the disease outcome in severe human cases. Further elucidating these tipping points by studying zoonotic viral infections in their reservoir hosts may teach us how to reduce the severity of zoonotic viral diseases in humans.

Trends in Bacterial Pathogens of Bats: Global Distribution and Knowledge Gaps

Bats have received considerable recent attention for infectious disease research because of their potential to host and transmit viruses, including Ebola, Hendra, Nipah, and multiple coronaviruses. These pathogens are occasionally transmitted from bats to wildlife, livestock, and to humans, directly or through other bridging (intermediate) hosts. Due to their public health relevance, zoonotic viruses are a primary focus of research attention. In contrast, other emerging pathogens of bats, such as bacteria, are vastly understudied despite their ubiquity and diversity. Here, we describe the currently known host ranges and geographic distributional patterns of potentially zoonotic bacterial genera in bats, using published presence-absence data of pathogen occurrence. We identify apparent gaps in our understanding of the distribution of these pathogens on a global scale. The most frequently detected bacterial genera in bats are Bartonella, Leptospira, and Mycoplasma. However, a wide variety of other potentially zoonotic bacterial genera are also occasionally found in bats, such as Anaplasma, Brucella, Borrelia, Coxiella, Ehrlichia, Francisella, Neorickettsia, and Rickettsia. The bat families Phyllostomidae, Vespertilionidae, and Pteropodidae are most frequently reported as hosts of bacterial pathogens; however, the presence of at least one bacterial genus was confirmed in all 15 bat families tested. On a spatial scale, molecular diagnostics of samples from 58 countries and four overseas departments and island states (French Guiana, Mayotte, New Caledonia, and Réunion Island) reported testing for at least one bacterial pathogen in bats. We also identified geographical areas that have been mostly neglected during bacterial pathogen research in bats, such as the Afrotropical region and Southern Asia. Current knowledge on the distribution of potentially zoonotic bacterial genera in bats is strongly biased by research effort towards certain taxonomic groups and geographic regions. Identifying these biases can guide future surveillance efforts, contributing to a better understanding of the ecoepidemiology of zoonotic pathogens in bats.