Search Results (313)

Poxviruses are large double-stranded DNA (dsDNA) viruses that cause important human and animal diseases, including smallpox and mpox. Poxviruses have also been identified in diverse bat populations; however, their potential for zoonotic transmission and adaptation to other mammalian hosts remains poorly understood. Poxviruses encode numerous immunomodulatory proteins that contribute to virulence, immune evasion, and host range. In this study, we performed a comparative genomic analysis of two bat-associated poxviruses belonging to the genus Vespertilionpoxvirus: hypsugopox virus (HYPV) and eptesipox virus (EPTV). Our analyses revealed 24 novel putative ORFs in HYPV and three in EPTV, thereby substantially expanding the inferred coding capacity of these viruses. Comparative analyses further revealed gene duplication and fragmentation events affecting several virulence and host range factors, as well as other unusual genomic features, including the presence of two divergent E3L homologs in EPTV. Together, our findings provide new insights into the genome evolution and potential host adaptation of bat-associated poxviruses and establish a foundation for future functional studies of Vespertilionpoxvirus biology, host–virus interactions, and zoonotic potential. Full article

In Cambodia, livestock production plays an important role in the national economy and food security, yet tick-borne diseases remain an underrecognized constraint on animal health and productivity. Domestic animals may also serve as reservoirs of zoonotic pathogens in this predominantly rural setting. To address the lack of baseline molecular data on tick-borne pathogens in Cambodia, we conducted a cross-sectional study of ticks collected from November 2022 to April 2023 across 24 provinces. Ticks were collected from various hosts and environments, including cats, cattle, dogs, goats, pangolins, pythons, wild pigs, and bat cave floors, representing urban, rural, farm, wildlife rescue center, and forest fringe habitats. A total of 1526 ticks belonging to nine species were pooled into 352 samples and screened using conventional PCR (cPCR) targeting Anaplasma, Ehrlichia, Babesia, and Coxiella. Additionally, a subset of Rhipicephalus microplus ticks was analyzed using metatranscriptomic next-generation sequencing (NGS). Rhipicephalus microplus ticks collected from cattle tested positive for Anaplasma marginale (1.1% of pools) and Ehrlichia minasensis (0.9% of pools), whereas Rhipicephalus linnaei ticks collected from dogs were positive for Anaplasma platys (0.3% of pools) and Babesia canis (2.0% of pools). A high prevalence of Coxiella-like endosymbionts (15.6% of pools) was found in R. microplus from both cattle and goats. Metatranscriptomic analysis also identified six tick-associated viruses in R. microplus from cattle; with Guangdong tick manly virus being the most dominant (32.5% of samples); followed by Zhangzhou Totiv tick virus 1 (15.0%), Jingmen tick virus (5.0%), and Mogiana tick virus; Rhipicephalus-associated rhabdo-like virus; and Rhipicephalus-associated flavi-like virus; each at 2.5%. These findings provide the first molecular evidence of numerous bacterial, protozoal, and viral pathogens circulating in R. microplus and R. linnaei in Cambodia. The study highlights the need for integrated One Health surveillance to better understand, prevent, and control tick-borne diseases in the region. Full article

Arthropod-borne viruses (arboviruses) cause a wide range of acute and chronic diseases and represent a growing global health burden. Although some vaccines exist, antiviral therapies remain limited. Identifying host restriction factors may enable new therapeutic strategies. We previously showed that bacterial effector proteins can serve as tools to uncover innate immune defenses. Here, we used a bacterial effector screen in bat cells to identify host factors restricting the arboviruses Sindbis virus (SINV) and O’nyong’nyong virus (ONNV). Several effectors enhanced infection by both viruses. However, we found the Shigella flexneri-encoded E3 ubiquitin ligase IpaH2 to selectively promote SINV replication. IpaH2 enhanced SINV infection across multiple mammalian cell lines, suggesting that it targets a conserved antiviral mechanism, and this effect required IpaH2 E3 ubiquitin ligase activity. Screening of putative IpaH2 host targets identified via ubiquitin-activated interaction trap (UBAIT) assays revealed the host factors ATP-binding cassette sub-family F member 3 (ABCF3) and Plakophilin-2 (PKP2) to play roles in restricting SINV infection. While ABCF3 broadly restricted multiple viruses, PKP2 specifically limited SINV replication, indicating a virus-specific restriction factor. These findings demonstrate that bacterial effector screening can identify both broadly acting and virus-specific host defenses, providing insight into antiviral mechanisms and potential therapeutic targets. Full article

Aedes (Ae.) aegypti and Ae. albopictus are important vectors of arboviruses. Yet their blood-feeding pattern remains poorly characterised in Africa, including Cameroon. In this study, we characterised the blood-meal sources in both species collected from vegetation, household surroundings, and animal cages across four urban sites, one rural site, and a zoo-botanical garden where humans and animals in captivity are the main hosts. Overall, Aedes mosquitoes represented about half of 10,054 female mosquitoes collected, with Ae. albopictus strongly dominating Ae. aegypti among 5001 Aedes females, and only 5.95% of females visibly blood-fed. Sequencing a 748 base pairs (bp) fragment of the cytochrome oxidase I gene from 156 blood-fed abdomens yielded 126 high-confidence host assignments, of which 98.25% were humans, indicating a strong anthropophagic pattern in both species. Unpredictably, two Ae. albopictus individuals had fed on a baboon (Papio anubis) and a frugivorous bat (Pteropodidae), as confirmed by bio informatic analyses, highlighting the species’ opportunistic blood-feeding nature and providing preliminary molecular evidence consistent with a potential bridge-vector role in this setting. Despite the extreme anthropophagy of both species observed, results indicate that Ae. albopictus could also serve as a bridge vector enabling spillover of enzootic viruses to humans, including urbanised settings where wild animals are present. These findings emphasise the urgent need for enhanced arbovirus surveillance in Central Africa using a One Health approach. Full article

The recent SARS-CoV-2 pandemic—which had significant worldwide health, economic, and other effects—indicated the need to monitor zoonotic viruses with pandemic potential. The aim of this review is to assess bat-borne viruses as a potential pandemic risk, with a particular focus on Europe. The presence and activity of bats, as well as diseases emerging in humans in various regions of the world, point to their importance in the context of a possible outbreak of future epidemics. The rate of genetic change observed among viruses requires constant scrutiny on all continents, including Europe. Bats are a considerable source of many zoonotic viruses, including coronaviruses, filoviruses and paramyxoviruses. Among viruses associated with bats, RNA viruses are the dominant ones, characterized by high pathogenicity and often leading to interspecies transmission. The majority (about 80%) of RNA viruses were identified in bats from three families: Vespertilionidae, Rhinolophidae and Pteropodidae. Understanding how viruses are transmitted in the environment and the role of reservoir organisms and intermediate hosts is crucial to determining the level of epidemic risk. This review discuses viruses identified in bats globally, with a special focus on Europe, and evaluates their potential to cause epidemics. Full article

Bats are reservoirs for many emerging viruses, yet broad-scale spatial patterns of bat viromes and their ecological determinants remain unclear, limiting spillover risk assessment. To address this, we conducted a standardized survey across central to southern China. During 2022–2023, fecal samples were collected from 527 bats representing 17 species at 21 caves in seven provinces. Using each cave as the analytical unit, samples from all species at a site were pooled to construct 21 fecal RNA virome libraries for metatranscriptomic sequencing; viral-like contigs were annotated, and viral alpha/beta diversity was quantified at the genus level. Sites were grouped by geographic distance and latitude to evaluate spatial differentiation and to relate virome patterns to host community attributes and environmental factors. We annotated 56 viral families, including 19 vertebrate-associated families, with multiple families and genera shared across geographic groupings. Vertebrate-associated viral diversity showed limited evidence of geographic isolation within the study region but suggested gradual turnover with latitude. Host species richness was the strongest correlate of virome diversity, exceeding the effects of evaluated environmental variables (e.g., climate and human activity). These results support prioritization of species-rich bat habitats for surveillance and risk assessment. Full article

The rapid evolution of coronaviruses (CoVs) requires researchers to develop specific yet broad-spectrum detection methods to monitor their constant genomic changes. The goal of the present study was to establish a current pan-coronavirus RT-PCR system capable of detecting a wide variety of CoVs and useful for the investigation of virus diversity and host spectrum. For optimization, one-step and two-step nested RT-PCRs with three RT enzymes were examined, amplifying a ~600 bp long product of the RNA-dependent RNA polymerase. As templates, the in vitro transcribed RNA of ten pathogenic CoVs (SARS-CoV, SARS-CoV-2, NL-63, OC43, feline CoV, porcine epidemic diarrhea virus or PEDV, transmissible gastroenteritis virus or TGEV, canine CoV, bat CoV, and infectious bronchitis virus) were applied instead of the often-used DNA standards. A limit of detection of 5–50 copies/reaction was achieved with a random hexamer-primed two-step RT-PCR and a touchdown cycling profile, representing a lower detection limit and higher specificity compared to previously published primer sets. Swine origin pooled samples (n = 121), collected from apparently healthy herds in Hungary, were tested with the novel RT-PCR system. Sequences of porcine respiratory CoV/TGEV and porcine hemagglutinating encephalomyelitis virus were identified in 24 oral fluid and nasal swab pools, demonstrating the circulation of these viruses in this country, as well as the suitability of the new PCR for their detection. The results highlighted the importance of adequate RT enzyme selection and the use of RNase inhibitors in sample preparation and conservation. Full article

Bats are vital parts of ecosystems but also act as important reservoirs of viruses that can infect humans. Studying bat-borne viruses is essential for preventing spillover events, and passive surveillance offers a promising, bat-friendly approach. Among these viruses, lyssaviruses are a major public health concern because infection in humans is almost always fatal. In Europe, the European bat lyssavirus type 1 (EBLV-1) is the most widespread. We aimed to expand the Hungarian rabies surveillance system into a One Health-based passive surveillance framework for multiple bat viruses, using lyssaviruses and filoviruses as examples. Dead-found or injured bats that died despite care were collected for examination. In total, 208 bats from 15 species were tested for lyssaviruses and Lloviu virus. Three serotine bats (Cnephaeus serotinus, formerly Eptesicus) tested positive for EBLV-1, and complete viral genomes were obtained. All sequences belonged to the EBLV-1a lineage, closely related to previously described Hungarian strains. All bats tested negative for Lloviu virus. These results confirm the feasibility of passive surveillance for detecting bat-borne viruses and highlight the importance of collaborative monitoring systems for future zoonotic outbreak preparedness. Full article

Bats, as the world’s second-largest mammalian order, have garnered significant attention for their ability to harbor numerous viruses without exhibiting disease symptoms. Nucleotide-binding domain and leucine-rich repeat-containing receptors (NLRs) are crucial components of the immune system. This study conducted an evolutionary analysis of the NLR gene family across 26 bat species to investigate the molecular mechanisms underlying their role in viral resistance under high viral load pressure. We identified gene duplication events in multiple genes. The NLR gene family exhibited high conservation throughout evolution, which may contribute to the occurrence of gene duplication. This conserved genomic structure also ensures functional stability, safeguarding bats’ antiviral resistance. Most NLR genes primarily function within the type I interferon (IFN) signaling pathway and the NF-κB signaling pathway. The NLR gene family enhances the innate immune capacity of bats through the adaptive evolution of some genes, combining enhanced gene functionality with the maintenance of gene conservation at a low evolutionary rate. Moreover, bats employ diverse innate immune strategies, where multiple immune pathways collectively establish the innate immune barrier. The molecular evolution of this gene family provides new insights into the molecular mechanisms and functional pathways involved in the innate immune response of bats. Full article

Bats have been identified as reservoir hosts for an exceptional diversity of viruses, including multiple taxa of high zoonotic concern. Over a hundred bat species inhabit Vietnam, which, combined with significant biodiversity, carry high risk of zoonotic spillover due to dense human–animal interfaces, extensive wildlife trade, and proximity to recent outbreak epicenters. This review systematically synthesizes data on the bat virome in Vietnam and neighboring Southeast Asian countries, assessing viral diversity, host species involvement, and zoonotic potential. By prioritizing virus groups with established zoonotic capacity and pandemic potential, the systematic search identified studies reporting viruses from 32 families across 13 bat families. Based on the WHO 2024 risk classification, seven of these viral families were categorized as high-risk, three as medium-risk, and twelve as low-risk. The comparatively higher viral diversity reported in neighboring countries suggests that the current study likely represents an underestimation of the true virome present in Vietnamese bat populations. We emphasize the urgent need for expanded virological studies integrating metagenomic sequencing, serological surveys, and ecological modeling to improve early detection of emerging threats, as the comparatively higher viral diversity reported in neighboring countries suggests existing research likely represents an underestimation of the true virome present in Vietnamese bat populations. Strengthening regional collaboration is critical for establishing proactive pandemic prevention strategies in this high-risk zoonotic hotspot. Full article

Bats are natural reservoirs for diverse viruses, yet they rarely develop disease, suggesting unique antiviral adaptations. In this study, we performed a comprehensive genome-wide analysis in the common vampire bat (Desmodus rotundus), integrating comparative genomics, functional annotation, microRNA (miRNA) discovery, target prediction, and network-based analyses. Comparative genomic analysis revealed that Phyllostomus discolor exhibits the highest protein homology (97.4%) with D. rotundus. Alignment of interferon regulatory factors (IRFs) indicated strong conservation of IRF1, IRF5, and IRF8, while IRF4 and IRF7 showed divergence, reflecting bat-specific modulation of interferon signaling. Functional annotation of previously uncharacterized proteins identified immune-related elements, including toll-like receptor 4, syncytin-1, and endogenous retroviral sequences, highlighting the integration of viral components into host immunity. We further identified 19 novel miRNAs in D. rotundus, with high-confidence target genes such as SOD2, TRIM28, and FGFR1 involved in antiviral defense, apoptosis regulation, and oxidative stress response. Functional enrichment analyses revealed processes associated with wound healing, apoptosis suppression, infection response, and longevity. Network entropy analysis highlighted central regulatory hubs, including MYC, BCL2, and KIF1B, influencing cell cycle, survival, and immune balance. Collectively, these results demonstrate that D. rotundus employs an integrated regulatory network combining conserved immune factors, lineage-specific gene divergence, and miRNA-mediated fine-tuning to achieve viral tolerance without pathology. This study expands our understanding of bat antiviral biology and provides candidate molecular targets for future functional and translational research. Full article

Bats host a wide range of viruses, including several high-profile pathogens of humans and other animals. The COVID-19 pandemic raised the level of concern regarding the risk of spillover of bat-borne viruses to humans and, conversely, human-borne viruses to bats. From August 2020 to July 2021, we conducted viral surveillance on 254 bats from 10 species across urban, periurban, and rural environments in New Mexico, USA. We used a pan-coronavirus RT-PCR to assay rectal swabs and performed metagenomic sequencing on a representative subset of 14 rectal swabs and colon samples. No coronaviruses were detected by either RT-PCR or metagenomic sequencing. However, four novel viruses were identified: an adenovirus (proposed name lacepfus virus, LCPV), an adeno-associated virus (AAV), an astrovirus (AstV), and a genomovirus (GV). LCPV, detected in a big brown bat (Eptesicus fuscus), is more closely related to canine adenoviruses than to other bat adenoviruses, suggesting historical transmission between bats and dogs. All virus-positive bats were either juvenile or adult individuals captured in urban environments; none exhibited obvious clinical signs of disease. Our findings suggest limited or no circulation of enzootic coronaviruses or SARS-CoV-2 in southwestern U.S. bat populations during the study period. The discovery of a genetically distinct adenovirus related to canine adenoviruses highlights the potential for cross-species viral transmission and underscores the value of continued virome surveillance in animals living with and near humans. Full article

In May 2022, an expedition was conducted in the Gobi Desert, Mongolia, to investigate the viral diversity of bats, recognized as reservoirs of emerging zoonotic viruses. Bats were captured in six oases using mist nets and were identified morphologically and molecularly. Fecal samples were collected and screened using molecular protocol targeting viral agents of relevance to human and animal health, including coronaviruses, orthoreoviruses, herpesviruses, adenoviruses, flaviviruses, phleboviruses, paramyxoviruses, pestiviruses, and Influenza A viruses. In total, 74 bats were sampled. The most represented bat genus was Plecotus, followed by Hypsugo, Vespertilio, and Myotis. Coronavirus RNA was detected in eleven samples (14.86%), Mammalian orthoreovirus RNA in two samples (2.70%), and herpesvirus DNA in three samples (4.05%). No other targeted viruses were detected. These data expand our understanding of viral circulation in bats from previously unstudied regions. By expanding our understanding of the viral diversity harbored by bats, this study contributes to ongoing efforts to better characterize their role in the ecology and evolution of emerging zoonotic viruses. Continuous surveillance in remote and biodiverse areas is essential to identify potential threats to public and animal health and to improve preparedness for future viral emergence. Full article

COVID-19 is the most widespread emerging infectious disease in humans, recently caused by the SARS-CoV-2 virus. Understanding the pathogenesis and development of efficient vaccines is crucial for the prevention and control of this emerging disease. SARS-CoV-2 viruses have widespread hosts, including humans, domesticated/companion animals (cats, dogs), specific farmed animals (minks), specific wildlife (white-tailed deer), and laboratory animal models. Bats are considered the original reservoir, and pangolins may be important intermediate hosts. Suitable animal models play an important role in studying the pathogenicity and evaluation of vaccines and antiviral drugs during the preclinical stage. In this review, we summarized the animal models and potential animal models for the research of SARS-CoV-2 pathogenesis, vaccine and antiviral drugs development, including transgenic mice, cats, hamsters, nonhuman primates, ferrets, and so on. Our summary provides the important information to select the animals used for a specific purpose and facilitates the development of novel vaccines and antivirals to prevent and control COVID-19. Full article