Bats are increasingly studied for their ability to coexist with diverse viruses of human health importance. While this focus has yielded insights into host–pathogen dynamics, baseline physiological data from healthy bats remain limited, constraining comparative and mechanistic understanding. Serum proteomics offers a direct window into circulating proteins that underpin immune regulation, cellular maintenance, and metabolism. Here, we characterize the serum proteome of clinically healthy, captive Egyptian rousette bats (Rousettus aegyptiacus), the only known natural reservoir host species of Marburg virus. Using untargeted proteomic profiling, we identified and ranked over 400 proteins across major functional categories. Prominent findings included extensive representation of complement components spanning all activation pathways, high levels of interferon-responsive proteins, and abundant proteasome subunits, including immunoproteasome components. The dataset further revealed a robust profile of oxidoreductases and antioxidant enzymes, consistent with mechanisms of redox balance and iron regulation, alongside an apolipoprotein profile suggestive of dietary specialization. An unexpected finding was the unusually high abundance of type XX collagen, potentially linked to tissue remodeling demands of flight. Exploratory sex-based analyses suggested trends in stress response and immune-related proteins, although sample size limited statistical resolution. This work provides the first-look of the Egyptian rousette bat serum proteome, providing a reference point for cross-species comparisons and future studies of bat immunity, metabolism, and longevity. By identifying constitutive molecular features in healthy individuals, these findings expand the use of proteomics for understanding non-traditional model organisms and set the stage for future targeted functional investigations.

Environmental air sampling holds significant potential as a tool for viral surveillance. Its use in agricultural and indoor settings has demonstrated its feasibility and effectiveness but despite this, it has rarely been used in wildlife settings. To enable future applications, we optimized key parameters in air sampling methodology using a cave-roosting bat assemblage as a model system. We systematically investigated the impact of sampling conditions (flow rate, sampling duration, and sampling location/deployment time) and post-sampling treatments (DNA/RNA Shield ratios and secondary filtration) on three viral metrics – total mammalian virus abundance, mammalian RNA virus abundance, and Shannon diversity index – generated from next-generation sequencing data. We first showed that air sampling can recover broad viral diversity, including alphacoronaviruses and betacoronaviruses. The sampling conditions for maximizing viral metrics were larger air sample volumes (≥24,000 liters) and sampling inside the cave while the bats were roosting, as opposed to at the cave entrance during emergence. Post-sampling treatments had limited impact on viral metrics, but their application may vary depending on the objectives of the study. This work provides a proof-of-concept for applying air sampling for wildlife viral surveillance in a cave-roosting bat assemblage and identifies key sampling parameters.

ABSTRACT Forecasting zoonotic risk requires identifying which host species are biologically susceptible to infection, yet susceptibility is rarely predicted using frameworks that integrate molecular mechanisms with macroecology. Filoviruses, a diverse group of bat-associated viruses that include Ebola and Marburg viruses, illustrate this challenge: viral entry depends on interactions between viral glycoproteins and the host receptor NPC1, and host ecology and distribution determine opportunity of viral entry. Additionally, receptor sequence data used for informing viral entry are available for only a small fraction of bat species. Here, we extend virus-specific susceptibility prediction across the global diversity of bats by integrating experimentally measured and physicochemically inferred virus–receptor binding strengths with phylogenetic, ecological, and environmental data. Using boosted regression models trained on binding assay labels, we generate predictions of NPC1-mediated binding strength for more than 1,300 bat species. Predicted susceptibility is strongly structured by evolutionary relationships, with high binding concentrated in particular bat lineages, but is further differentiated within clades by morphology, life-history strategy, and environmental context. Strikingly, macroevolutionary structure alone recovers interaction patterns originally derived from amino acid–level physicochemistry, indicating that information about receptor-mediated compatibility is recoverable from host evolutionary history and ecological traits. Predicted high binding strength extends well beyond historically recognized outbreak regions, suggesting that the fundamental host range of filoviruses may be substantially broader than their currently realized distribution. By scaling receptor biology to global host diversity, this multi-scale framework expands mechanistic susceptibility forecasting beyond species with available molecular data and provides a generalizable approach for integrating molecular and ecological information in zoonotic prediction.

Biologists are increasingly interested in the ecological and evolutionary factors that influence microbial communities. Yet compared to bacterial communities, our understanding of viral community ecology remains limited. Here, we investigated the factors influencing viral community composition and structure among wild rhesus macaques (Macaca mulatta) in human-modified environments in Bangladesh, focusing on assemblages of picobirnaviruses (PbVs) as a model system. We found that anthropogenic factors-particularly human and livestock densities-were the strongest predictors of viral community composition. Host social organisation played a secondary role, shaping viral communities at the group and site levels. Virus-virus associations influenced co-occurrence patterns primarily within individual hosts, but their effect became less evident at broader scales. In contrast, individual host traits (age, sex and physiological stress) and viral phylogenetic relationships had minimal effects on viral co-occurrence. Notably, anthropogenic factors had opposing effects on different PbV taxa: While some viruses were more prevalent in areas with higher human and livestock densities, others were less common, possibly due to their association with wildlife or natural environments. This suggests that macaques may acquire certain PbVs from anthropogenic sources while experiencing reduced exposure to others in human-modified landscapes. Together, these findings reveal the dominant role of environmental and social factors in shaping viral communities and highlight the hierarchical nature of virus community assembly-with different ecological processes operating at individual, group and site scales.

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Coronaviruses (CoVs) continue to pose a global health threat as they spill over from animal hosts to humans. The Coalition for Epidemic Preparedness Innovations (CEPI) is a global partnership focused on vaccine research and development. CEPI's CoV Vaccine Library initiative aims to generate knowledge and tools to accelerate vaccine development against emergent CoVs, prioritizing those with the highest assessed risk of spillover, vaccine feasibility, and phylogenetic coverage. Based on expert consultations and published data, we developed a prioritized list of 26 CoVs to serve as a foundation for building a knowledge base to support future vaccine efforts. As a first step, in silico designs will be used to develop stabilized spike antigens for select targets. These antigens will be tested for pre-clinical immunogenicity and breadth using different vaccine modalities. Assays, tools, and data generated will nucleate an open-access library and serve as a starting point for emergent CoV vaccine development.

In the United States (US), biosafety and biosecurity oversight of research on viruses is being reappraised. Safety in virology research is paramount and oversight frameworks should be reviewed periodically. Changes should be made with care, however, to avoid impeding science that is essential for rapidly reducing and responding to pandemic threats as well as addressing more common challenges caused by infectious diseases. Decades of research uniquely positioned the US to be able to respond to the COVID-19 crisis with astounding speed, delivering life-saving vaccines within a year of identifying the virus. We should embolden and empower this strength, which is a vital part of protecting the health, economy, and security of US citizens. Herein, we offer our perspectives on priorities for revised rules governing virology research in the US.

Public health concerns about recent viral epidemics have motivated researchers to seek novel ways to understand pathogen infection in native, wildlife hosts. With its deep history of tools and perspectives for understanding the abundance and distribution of organisms, ecology can shed new light on viral infection dynamics. However, datasets allowing deep explorations of viral communities from an ecological perspective are lacking. We sampled 1,086 bats from two, adjacent Puerto Rican caves and tested them for infection by herpesviruses, resulting in 3,131 short, viral sequences. Using percent identity of nucleotides and a machine learning algorithm (affinity propagation), we categorized herpesviruses into 43 operational taxonomic units (OTUs), to be used in place of species in subsequent ecological analyses. Herpesvirus metacommunities demonstrated long-tailed rank frequency distributions at all analyzed levels of host organization (i.e., individual, population, and community). Although 13 herpesvirus OTUs were detected in more than one host species, OTUs generally exhibited host specificity by infecting a single core host species at a significantly higher prevalence than in all satellite species combined. We describes the natural history of herpesvirus metacommunities in Puerto Rican bats and suggest that viruses follow the general law that communities comprise few common and many rare species. To guide future efforts in the field of viral ecology, hypotheses are presented regarding mechanisms that contribute to these patterns.

Coronavirus genomes have evolutionary histories shaped extensively by recombination. Yet, how often recombination occurs at a cellular level, or the factors that regulate recombination rates, are poorly understood. Utilizing experimental co-infections with pairs of genetically distinct coronaviruses, we found that recombination is both frequent and rare during coinfection. Recombination occurred in every instance of co-infection yet resulted in relatively few recombinant RNAs. By integrating a discrete-time Susceptible-Infected-Removed (SIR) model, we found that rates of recombination are determined primarily by rates of cellular co-infection, rather than other possible barriers such as RNA compartmentalization. By staggering the order and timing of infection with each virus we also found that rates of co-infection are themselves heavily influenced by genetic and ecological mechanisms, including superinfection exclusion and the relative fitness of competing viruses. Our study highlights recombination as a potent yet regulated force: frequent enough to ensure a steady influx of genetic variation but also infrequent enough to maintain genomic integrity. As recombination is thought to be an important driver of host-switching and disease emergence, our study provides new insights into the factors that regulate coronavirus recombination and evolution more broadly.

Centrosome amplification is a feature of cancer cells associated with chromosome instability and invasiveness. Enhancing chromosome instability and subsequent cancer cell death via centrosome unclustering and multipolar divisions is an aimed-for therapeutic approach. Here, we show that centrosome amplification potentiates responses to conventional chemotherapy in addition to its effect on multipolar divisions and chromosome instability. We perform single-cell live imaging of chemotherapy responses in epithelial ovarian cancer cell lines and observe increased cell death when centrosome amplification is induced. By correlating cell fate with mitotic behaviors, we show that enhanced cell death can occur independently of chromosome instability. We identify that cells with centrosome amplification are primed for apoptosis. We show they are dependent on the apoptotic inhibitor BCL-XL and that this is not a consequence of mitotic stresses associated with centrosome amplification. Given the multiple mechanisms that promote chemotherapy responses in cells with centrosome amplification, we assess such a relationship in an epithelial ovarian cancer patient cohort. We show that high centrosome numbers associate with improved treatment responses and longer overall survival. Our work identifies apoptotic priming as a clinically relevant consequence of centrosome amplification, expanding our understanding of this pleiotropic cancer cell feature.

APOBEC3, an enzyme subfamily that plays a role in virus restriction by generating mutations at particular DNA motifs or mutational "hotspots," can drive viral mutagenesis with host-specific preferential hotspot mutations contributing to pathogen variation. While previous analysis of viral genomes from the 2022 Mpox (formerly Monkeypox) disease outbreak has shown a high frequency of C>T mutations at T C motifs, suggesting recent mutations are human APOBEC3-mediated, how emerging monkeypox virus (MPXV) strains will evolve as a consequence of APOBEC3-mediated mutations remains unknown. By measuring hotspot under-representation, depletion at synonymous sites, and a combination of the two, we analyzed APOBEC3-driven evolution in human poxvirus genomes, finding varying hotspot under-representation patterns. While the native poxvirus molluscum contagiosum exhibits a signature consistent with extensive coevolution with human APOBEC3, including depletion of T C hotspots, variola virus shows an intermediate effect consistent with ongoing evolution at the time of eradication. MPXV, likely the result of recent zoonosis, showed many genes with more T C hotspots than expected by chance (over-representation) and fewer G C hotspots than expected (under-representation). These results suggest the MPXV genome: 1) may have evolved in a host with a particular APOBEC G C hotspot preference, 2) has inverted terminal repeat (ITR) regions -which may be exposed to APOBEC3 for longer during viral replication- and longer genes likely to evolve faster, and therefore 3) has a heightened potential for future human APOBEC3-meditated evolution as the virus spreads in the human population. Our predictions of MPXV mutational potential can both help guide future vaccine development and identification of putative drug targets and add urgency to the task of containing human Mpox disease transmission and uncovering the ecology of the virus in its reservoir host.

ABSTRACT Centrosome amplification is a feature of cancer cells associated with chromosome instability and invasiveness. Enhancing chromosome instability and subsequent cancer cell death via centrosome unclustering and multipolar divisions is an aimed-for therapeutic approach. Here we show that centrosome amplification favors responses to conventional chemotherapy independently of multipolar divisions and chromosome instability. We perform single-cell live imaging of chemotherapy responses in epithelial ovarian cancer cell lines and observe increased cell death when centrosome amplification is induced. By correlating cell fate with mitotic behaviors, we show that enhanced cell death occurs independently of chromosome instability. We identify that cells with centrosome amplification are primed for apoptosis. We show they are dependent on the apoptotic inhibitor BCL-XL, and that this is not a consequence of mitotic stresses associated with centrosome amplification. Given the multiple mechanisms that promote chemotherapy responses in cells with centrosome amplification, we assess such a relationship in an epithelial ovarian cancer patient cohort. We show that high centrosome numbers associate with improved chemotherapy responses and longer overall survival. Our work identifies apoptotic priming as a clinically relevant consequence of centrosome amplification, expanding our understanding of this pleiotropic cancer cell feature.

Morbilliviruses are among the most contagious viral pathogens of mammals. Although previous metagenomic surveys have identified morbillivirus sequences in bats, full-length morbilliviruses from bats are limited. Here we characterize the myotis bat morbillivirus (MBaMV) from a bat surveillance programme in Brazil, whose full genome was recently published. We demonstrate that the fusion and receptor binding protein of MBaMV utilize bat CD150 and not human CD150, as an entry receptor in a mammalian cell line. Using reverse genetics, we produced a clone of MBaMV that infected Vero cells expressing bat CD150. Electron microscopy of MBaMV-infected cells revealed budding of pleomorphic virions, a characteristic morbillivirus feature. MBaMV replication reached 103–105 plaque-forming units ml−1 in human epithelial cell lines and was dependent on nectin-4. Infection of human macrophages also occurred, albeit 2–10-fold less efficiently than measles virus. Importantly, MBaMV is restricted by cross-neutralizing human sera elicited by measles, mumps and rubella vaccination and is inhibited by orally bioavailable polymerase inhibitors in vitro. MBaMV-encoded P/V genes did not antagonize human interferon induction. Finally, we show that MBaMV does not cause disease in Jamaican fruit bats. We conclude that, while zoonotic spillover into humans may theoretically be plausible, MBaMV replication would probably be controlled by the human immune system. Characterization of the myotis bat morbillivirus shows that infection in human cells is restricted by innate immune responses in vitro and cross-neutralization by sera from measles, mumps and rubella vaccinees.

Recombination is thought to be a mechanism that facilitates cross-species transmission in coronaviruses, thus acting as a driver of coronavirus spillover and emergence. Despite its significance, the mechanism of recombination is poorly understood, limiting our potential to estimate the risk of novel recombinant coronaviruses emerging in the future. As a tool for understanding recombination, here, we outline a framework of the recombination pathway for coronaviruses. We review existing literature on coronavirus recombination, including comparisons of naturally observed recombinant genomes as well as in vitro experiments, and place the findings into the recombination pathway framework. We highlight gaps in our understanding of coronavirus recombination illustrated by the framework and outline how further experimental research is critical for disentangling the molecular mechanism of recombination from external environmental pressures. Finally, we describe how an increased understanding of the mechanism of recombination can inform pandemic predictive intelligence, with a retrospective emphasis on SARS-CoV-2.

Bats are important hosts of zoonotic viruses with pandemic potential, including filoviruses, MERS-Coronavirus (CoV), SARS-CoV -1, and likely SARS-CoV-2. Viral infection and transmission among wildlife are dependent on a combination of factors that include host ecology and immunology, life history traits, roosting habitats, biogeography, and external stressors. Between 2016 and 2018, four species of insectivorous bats from a readily accessed roadside cave and buildings in Ethiopia were sampled and tested for viruses using consensus PCR assays for five viral families/genera. Previously identified and novel coronaviruses and paramyxoviruses were identified in 99 of the 589 sampled bats. Bats sampled from the cave site were more likely to test positive for a CoV than bats sampled from buildings; viral shedding was more common in the wet season; and rectal swabs were the most common sample type to test positive. A previously undescribed alphacoronavirus was detected in two bat species from different taxonomic families, sampling interfaces, geographic locations, and years. These findings expand knowledge of the range and diversity of coronaviruses and paramyxoviruses in insectivorous bats in Ethiopia and reinforce that an improved understanding of viral diversity and species-specific shedding dynamics is important for designing informed zoonotic disease surveillance and spillover risk reduction efforts.

Host-virus associations have co-evolved under ecological and evolutionary selection pressures that shape cross-species transmission and spillover to humans. Observed virus-host associations provide relevant context for newly discovered wildlife viruses to assess knowledge gaps in host-range and estimate pathways for potential human infection. Using models to predict virus-host networks, we predicted the likelihood of humans as hosts for 513 newly discovered viruses detected by large-scale wildlife surveillance at high-risk animal-human interfaces in Africa, Asia, and Latin America. Predictions indicated that novel coronaviruses are likely to infect a greater number of host species than viruses from other families. Our models further characterize novel viruses through prioritization scores and directly inform surveillance targets to identify host ranges for newly discovered viruses.