Search Results (94)

The northeastern region of China is characterized by complex ecosystems, including forests and wetlands, and borders North Korea, Russia, and Mongolia. It serves not only as a natural reservoir for various microorganisms but also as a critical geographical and ecological hub for cross-border exchanges in Northeast Asia. Based on metagenomics and meta-transcriptomics investigations, this study systematically reviews the current research status of novel pathogens in the northeastern border region of China. It systematically organizes the newly discovered species, their classifications, and geographical distributions, with a focus on analyzing novel viruses that have potential pathogenicity to humans. The novel viruses identified in the northeastern border region belong to 11 viral families, including 9 from the Nairoviridae, 4 from the Rhabdoviridae, 3 each from the Astroviridae, Picornaviridae, and Parvoviridae, and 1–2 from other viral families, indicating a broad diversity of newly discovered viruses. These novel viruses are found in a wide range of hosts, including humans, ticks, minks, Marmota sibirica, and Myodes rufocanus, underscoring the significant public health risks these viruses pose. Geographically, the novel viruses discovered in the northeastern border region show a clustering pattern, with new species primarily concentrated in areas bordering Russia and North Korea. This highlights the unique role of the region as a hotspot for cross-border pathogen transmission and risk. The findings provide a systematic scientific reference for understanding the spectrum of unknown novel pathogens and their geographical distribution in the northeastern border region, assessing the risk of emerging infectious diseases, and optimizing active surveillance systems. Full article

Phlebotomine sand flies are dipterans that transmit leishmaniasis, bartonellosis, and arboviruses of public health importance. Colombia is a tropical country with high annual incidences of arboviruses, such as dengue and, more recently, yellow fever, all of which have similar symptoms. This study characterized the viruses circulating in phlebotomine sand flies in two departments in the Colombian Caribbean. Between August 2023 and December 2024, a descriptive study was conducted in the Departments of Córdoba and Cesar in Colombia. Four municipalities were selected per department, and four insect captures were performed using CDC light traps. Specimens were taxonomically identified and organized into groups according to species and study area, and total RNA was extracted for NGS analysis. Short sequences were quality-assessed, assembled using MEGAHIT to obtain contigs, and classified using DIAMOND-MEGAN6 to select viral genomic sequences for phylogenetic analysis. Thirteen viral families were identified, including a virus from the family Rhabdoviridae in Pi. evansi in the department of Cesar and another from the family Dicistroviridae in Lutzomyia gomezi in both departments. Two genome segments of the family Phenuiviridae were found in Lutzomyia gomezi in the department of Córdoba, Colombia. Sand flies harbor a diverse range of viral families, some of which are previously undescribed, and can be studied to determine their taxonomy and assess their potential to infect vertebrate cells or their interactions with medically important pathogens such as Leishmania spp. Full article

Oncolytic viruses (OVs) exploit key hallmarks of cancer to selectively replicate in malignant cells, leading to tumor cell lysis, modulation of the tumor microenvironment, and induction of antitumor immunity. These viral platforms have been engineered to enhance tumor specificity, intratumoral spread, and immunotherapeutic efficacy. Among them, rhabdoviruses, particularly vesiculoviruses, have emerged as promising candidates due to their rapid replication, high titers, and amenability to genetic manipulation. Maraba virus, a recently identified vesiculovirus, is a single-stranded negative-sense RNA virus with a favorable safety profile and minimal pre-existing immunity in humans. It demonstrates selective tumor tropism partly through low-density lipoprotein receptor (LDLR)-mediated entry and impaired antiviral responses in cancer cells. Genetic engineering of the wild-type Maraba virus led to the development of the MG1 strain, characterized by enhanced tumor selectivity, increased replication capacity, and potent cytolytic activity. Preclinical studies have demonstrated its efficacy as a monotherapy, a cancer vaccine vector expressing tumor-associated antigens, and in combination with chemotherapy and immune checkpoint inhibitors. MG1 also reshapes the tumor microenvironment, converting immunologically “cold” tumors into “hot” tumors, thereby enhancing immune-mediated tumor clearance. Compared to vesicular stomatitis virus, Maraba virus exhibits improved safety and reduced neurovirulence while maintaining strong oncolytic potential. This review aims to comprehensively summarize the biological characteristics of the MG1 Maraba virus, its genetic development, mechanisms of action, and current preclinical and clinical applications as a novel oncolytic immunotherapeutic agent. Full article

Macrosteles fascifrons, a representative aster leafhopper frequently detected in rice-growing environments, is an economically significant insect that inhabits rice fields and plays a role in the ecology of crop pests and disease transmission. To expand the understanding of viral diversity associated with the aster leafhopper, we analyzed its virome using deep transcriptome sequencing. In addition to several previously reported viruses, we identified two previously unreported RNA viruses, tentatively designated as Macrosteles fascifrons hepe-like virus 1 (MfHV1) and Macrosteles fascifrons rhabdovirus 1 (MfRV1). The complete genome sequences of both genomes were obtained using overlapping RT-PCR and rapid amplification of cDNA ends. Excluding the poly(A) tail, the genome of MfHV1 is 6688 nucleotides in length and exhibits a genomic organization characteristic of the family Hepeviridae, comprising three major open reading frames (ORFs) that encode a putative nonstructural polyprotein, a capsid protein, and a small accessory protein. The ORF encoding the capsid protein partially overlaps with the ORF encoding the small accessory protein, a genomic feature commonly observed in hepe-like viruses. The genome of MfRV1 is 14,984 nucleotides in length and displays the canonical genomic organization of the family Rhabdoviridae. An additional accessory ORF was identified between the putative M and G genes. Phylogenetic analysis based on polyprotein sequences placed MfHV1 within the Hepeviridae, most closely related to insect-associated hepe-like viruses, whereas MfRV1 clustered within the subfamily Deltarhabdovirinae. According to ICTV guidelines, virus classification is based on a combination of sequence divergence, phylogenetic relationships, and genome organization. MfHV1 and MfRV1 share low amino acid sequence identities with known viruses (maximum 36.07% for the MfHV1 polyprotein and 47.7% for the MfRV1 RNA-dependent RNA polymerase). Based on sequence divergence, genome organization, and phylogenetic placement, these viruses are classified as putative novel members of their respective families. This study expands the diversity of virus-associated sequences detected in M. fascifrons and provides additional genomic resources for understanding insect-associated RNA viruses. Full article

The autophagy regulator ATG7 helps maintain cellular homeostasis and has been suggested to modulate aspects of antiviral immune responses. In Drosophila, ATG7-dependent autophagy contributes to host resistance to vesicular stomatitis virus (VSV), a negative-strand RNA virus of family Rhabdoviridae that is widely used for studying viral biology and developing vaccines and virotherapy. However, the role of ATG7 in mammalian cells, especially non-immune cell types, remains unclear. Herein, we systematically examined the impact of ATG7 on VSV infection using CRISPR-edited cell lines derived from murine embryonic fibroblast (MEF), HeLa, and Huh7.5 cells, in relation to its effect on the expression of antiviral interferon-stimulated genes (ISGs). We found that ATG7 deficiency blocked basal as well as VSV-induced LC3B lipidation, concomitant with moderate reductions in progeny virus yields, while the reconstitution of ATG7 reversed the phenotypes. Mechanistically, ATG7 did not affect viral entry but rather was associated with moderate upregulation of VSV RNA replication. Intriguingly, ATG7 inhibited baseline ISG expression, and this correlated with its pro-VSV effect in all three cell types, while its suppression of innate immune responses elicited post-VSV infection did not. Altogether, these data provide new insights into the role of ATG7 in regulating VSV replication and innate immunity and have implications for developing VSV-based prophylaxis/therapeutics. Full article

Vesicular stomatitis virus (VSV), a member of the Vesiculovirus genus within the Rhabdoviridae family, is a widespread pathogen affecting all hoofed livestock species, leading to reduced animal growth and productivity. To date, no effective therapeutic treatment for VSV infection has been developed. Natural medicinal compounds with immunomodulatory properties represent a promising supportive strategy for infection control. Ginsenoside Rh1, a primary bioactive component of ginseng plants, has been reported to possess broad pharmacological and immunoregulatory activities. Nevertheless, its potential antiviral effects against VSV remain unexplored. In this study, we demonstrate that Ginsenoside Rh1 exhibits considerable antiviral activity against VSV in cellular models. Mechanistically, its antiviral effect is primarily mediated through the inhibition of VSV-induced autophagy, thereby enhancing interferon-mediated antiviral responses. Collectively, our findings identify Ginsenoside Rh1 as a novel antiviral agent active against VSV and potentially related vesiculoviruses, clarify its mechanism of action, and highlight an autophagy-dependent immunomodulatory approach that could be critical for confronting existing and emerging RNA viral infections. Full article

Haiti is a Caribbean country of about 11 million people with a high burden of mosquito-transmitted disease and limited vector control, thereby making effective operational mosquito control of high importance. Previous studies have examined vector-borne disease burden and insecticide resistance markers in Haitian Aedes and Anopheles mosquitoes, but not Culex species. In this study, we examined collections of Culex quinquefasciatus from 12 locations in northern and southern Haiti for the presence of markers of insecticide resistance (using a variety of target-site mutations and biochemical assays) and pathogens (using a deep-sequencing microbiome workflow). The metagenomic analysis identified Wolbachia, Rhabdoviridae, and Plasmodium infections in all sample pools at relatively high levels, along with less frequent detections of other potential pathogens. Insecticide resistance marker examination identified variable frequencies of knockdown resistance and acetylcholinesterase resistance mutations, as well as variation in resistance-associated enzymatic activities in these populations. These findings indicate that insecticide resistance to pyrethroid and organophosphate insecticides is likely. Although there was variation among Culex mosquito populations and no clear activity pattern, enzymatic activity was significantly higher at the southern sites than at the northern sites. Similar findings in Cx. quinquefasciatus populations in other locations in the Americas strongly suggest that vector control with pyrethroid and organophosphate adulticides may be of limited efficacy. Full article

Carpione rhabdovirus (CAPRV) is an emerging virus within the family Rhabdoviridae, posing potential threats to aquaculture species such as golden pompano (Trachinotus anak). However, since the 21st century, and for CAPRV strains isolated from marine fish, only a single CAPRV2023 sequence has previously been available in public databases, with no additional sequences reported. Because the virus undergoes genetic variation, relying on this single sequence likely introduced mismatches or off-target risks in earlier detection assay designs. Notably, the previously developed two-step N-targeting detection assay was designed based solely on that single CAPRV2023 sequence. Consequently, this study involved determining and analyzing the N gene sequences from CAPRV isolates gathered from 2023 to 2025, with the aim of pinpointing conserved regions for assay development, and sequence comparisons subsequently verified the existence of mismatches in the primer–probe binding sites of the previous assay. Since quantitative assays in aquatic virology often define copy numbers utilizing either plasmid DNA templates or RNA templates produced via in vitro transcription, which may lead to variations in amplification kinetics and sensitivity, this study compared both standards to ensure reliable quantification across different nucleic acid types. Based on these findings, a one-step TaqMan quantitative PCR (qPCR) assay was developed and validated using dual nucleic acid standards, namely plasmid DNA and in vitro–transcribed RNA. Compared with conventional two-step qPCR, the one-step format combines cDNA synthesis and subsequent DNA amplification in a single sealed tube, thereby effectively preventing cross-contamination, simplifying the workflow, and improving detection efficiency. The assay exhibited strong linearity (R² > 0.99) and consistent amplification efficiencies between 90% and 110%, demonstrating excellent quantitative performance. The detection limits were 2 copies per reaction for plasmid DNA and 20 copies for in vitro–transcribed RNA templates. No cross-reactivity was observed with other aquatic pathogens, and the assay showed strong repeatability and reproducibility (coefficients of variation below 2.0%), providing a sensitive and reliable tool for epidemiological surveillance and the analysis of CAPRV distribution in marine aquaculture systems of southern China. Full article

Citrus leprosis (CL) and citrus zonate chlorosis (ZC) were first described in Brazil in the 1930s. Both diseases, which caused non-systemic lesions primarily characterized by chlorotic and/or necrotic spots, were associated with the presence of Brevipalpus mites. While CL has since been well characterized as being caused by viruses of the genera Cilevirus (family Kitaviridae) and Dichorhavirus (family Rhabdoviridae) and transmitted by several species of Brevipalpus mites, the causal agent of ZC remained unknown. In this study, we analyzed Citrus spp. samples exhibiting typical ZC symptoms using high-throughput sequencing (HTS) to determine the etiology of ZC. We examined historical herbarium specimens collected between 1933 and 1965 alongside fresh samples collected from 2016 to 2022. Our results identified the higrevirus hibiscus green spot virus 2 (HGSV2, Higrevirus waimanalo) as the causal agent of ZC. In addition, we report for the first time the presence of a higrevirus in continental America, expand the diversity of known kitaviruses infecting citrus in Brazil, and demonstrate the transmission of an higrevirus by Brevipalpus yothersi and B. papayensis. Full article

Hyalomma ticks are known for their ability to transmit a wide range of pathogens, posing a significant threat to both human and animal health. The viral communities associated with Hyalomma asiaticum ticks in Kazakhstan remain largely unexplored. Using high-throughput sequencing on the Ion Torrent platform, nine RNA viruses belonging to seven families were identified. These viruses were associated with H. asiaticum ticks collected in 2024 in southern Kazakhstan. The detected viruses—including Bole tick virus 1 (Phenuiviridae), Bole tick virus 3 (Chuviridae), Bole tick virus 4 (Flaviviridae), Hubei toti-like virus 24 (Totiviridae), Kashgar totiv tick virus 1 (Totiviridae), Lonestar tick totivirus (Totiviridae), Qingyuan parti tick virus 1 (Partitiviridae), and Taishun tick virus (Rhabdoviridae)—had previously been reported only in China. This study provides the first documented evidence of the presence of RNA viruses previously unreported in Kazakhstan within H. asiaticum tick populations. A newly isolated Kazakhstan strain of Wad Medani virus (Sedoreoviridae), identified from H. asiaticum, shares genetic similarities with Russian strains, suggesting a common epidemiological landscape across Central Eurasia. The detection of novel RNA viruses in Kazakhstan highlights the need for ongoing surveillance, as their impact on human and animal health remains insufficiently understood. Full article

Lyssaviruses are RNA viruses in the Family Rhabdoviridae, Genus Lyssavirus. They represent the causative agents of acute, progressive encephalitis, known historically as rabies. Regardless of specific etiology, their collective viral morphology, biochemistry, pathobiology, associated clinical signs, diagnosis, epizootiology, and management are essentially the same. Despite centuries of clinical recognition, these quintessential neurotropic agents remain significant pathogens today, with substantive consequences to agriculture, public health, and conservation biology. Notably, the singular morbidity caused by lyssaviruses is incurable and constitutes the highest case fatality of any viral disease. All warm-blooded vertebrates are believed to be susceptible. The dog is the only domestic animal that serves as a reservoir, vector, and victim. In contrast, felids are effective vectors, but not reservoirs. All other rabid domestic species, such as livestock, constitute spillover infections, as a bellwether to local lyssavirus activity. Frequently, professional confusion abounds among the veterinary community, because although the viral species Lyssavirus rabies is inarguably the best-known representative in the Genus, at least 20 other recognized or putative members of this monophyletic group are known. Frequently, this is simply overlooked. Moreover, often the ‘taxonomic etiology’ (i.e., ‘Lyssavirus x’) is mistakenly referenced in a biopolitcal context, instead of the obvious clinical illness (i.e., ‘rabies’). Global consternation persists, if localities believe they are ‘disease-free’, when documented lyssaviruses circulate or laboratory-based surveillance is inadequate to support such claims. Understandably, professional chagrin develops when individuals mistake the epidemiological terminology of control, prevention, elimination, etc. Management is not simple, given that the only licensed veterinary and human vaccines are against rabies virus, sensu lato. There are no adequate antiviral drugs for any lyssaviruses or cross-reactive biologics developed against more distantly related viral members. While representative taxa among the mammalian Orders Chiroptera, Carnivora, and Primates exemplify the major global reservoirs, which mammalian species are responsible for the perpetuation of other lyssaviruses remains a seemingly academic curiosity. This zoonosis is neglected. Clearly, with such underlying characteristics as a fundamental ‘disease of nature’, rabies, unlike smallpox and rinderpest, is not a candidate for eradication. With the worldwide zeal to drive human fatalities from canine rabies viruses to zero by the rapidly approaching year 2030, enhanced surveillance and greater introspection of the poorly appreciated burden posed by rabies virus and diverse other lyssaviruses may manifest as an epidemiological luxury to the overall global program of the future. Full article

Negative-sense RNA viruses comprise a wide array of viral families, such as Orthomyxoviridae, Paramyxoviridae, Rhabdoviridae, and Morbillivirus, all of which are adept at inciting significant epidemic outbreaks. Throughout their replication cycle, these viruses engage in a variety of RNA modifications, during both the co-transcriptional and post-transcriptional phases, which are mediated by specific enzymatic activities. These chemical alterations play a critical role in shaping viral fitness, particularly in terms of evading innate immune responses. Key chemical modifications, such as adenosine methylation, 2′-O methylation of nucleosides, and adenosine-to-inosine editing, play critical roles in determining the stability, translational efficiency, and immune recognition of viral RNA. These modifications can reduce the activation of immune sensors, thereby suppressing interferon production and broader antiviral responses. In contrast, certain modifications may enhance immune recognition, which opens avenues for novel vaccine and antiviral strategy development. A comprehensive understanding of these RNA chemical modifications and their implications for virus–host interactions is essential for advancing therapeutic strategies aimed at manipulating innate immunity and optimizing the efficacy of RNA-based vaccines. This review examines the mechanisms and implications of RNA chemical modifications in negative-sense RNA viruses, emphasizing their dual roles in either evading or activating the innate immune system. Full article

In this report, we document and analyze a case in which the Irkut virus (IRKV) (Mononegavirales: Rhabdoviridae) caused a fatal human case following a bat bite in June 2021. Unfortunately, the available data did not permit a detailed taxonomic classification of the carrier bat (Chiroptera). The event occurred in the southwestern part of the Sikhote-Alin mountain region (Russian Far East) covered by the Ussuri taiga forest. The symptoms of the illness began with the following: fever; pronounced psychomotor and motor agitation; tremor of the lower jaw and tongue; aphasia; dyslexia; and dysphagia. These rapidly developed, leading to a severe and fatal encephalitis. The patient was not vaccinated for rabies and did not receive rabies immunoglobulin. Using brain sections prepared from the deceased, molecular diagnostics were performed: immunofluorescence (polyclonal anti-rabies immunoglobulin) indicating the presence of the lyssavirus antigen; and RT-PCR indicating traces of viral RNA. Sectional material (brain) was used for whole-genome sequencing, resulting in a near-complete sequence of the lyssavirus genome. The obtained genomic sequence was identified as the Irkut virus. A comparative analysis of the new sequence and other currently available IRKV sequences (NCBI) revealed differences. Specifically, amino acid differences between antigenic sites in the isolate and those of the rabies vaccine strain used regionally were noted. The patient history and subsequent analysis confirm human IRKV infection following bat contact. Like other fatal cases of IRKV infection described earlier, this case occurred in the southern part of the Russian Far East. Two have occurred in the southwestern part of the Sikhote-Alin mountain region. This indicates the possible existence of an active, natural viral focus. Full article

Dichorhavirus is a recently accepted plant virus genus within the family Rhabdoviridae. Species assigned to the genus consist of bi-segmented, negative sense, single-stranded RNA viruses and are transmitted by Brevipalpus spp. Currently, there are five recognized species and two unclassified members in the genus Dichorhavirus. Four out of seven-orchid fleck virus (OFV), citrus leprosis virus N, citrus chlorotic spot virus, and citrus bright spot virus-can infect citrus and produce leprosis disease-like symptoms. The E-probe Diagnostic for Nucleic Acid Analysis (EDNA) was developed to reduce computational effort and then integrated within Microbe-Finder (MiFi^®) online platform to design and evaluate e-probes in raw High Throughput Sequencing (HTS) data. During this study, Dichorhavirus genomes were downloaded from public databases and e-probes were designed using the MiProbe incorporated into the MiFi^® platform. Three different sizes of e-probes, 40, 60, and 80 nucleotides, were developed and selected based on whole genome comparisons with near-neighbor genomes. For curation, each e-probe was searched in the NCBI nucleotide sequence database using BLASTn. All the e-probes that had hits with non-target species with ≥90% identities were removed. The sensitivity and specificity of Dichorhavirus genus, species, strain, and variant-specific e-probes were validated in vivo using HTS meta-transcriptomic libraries generated from Dichorhavirus-suspected citrus, orchid, and ornamentals. Through downstream analysis of HTS data, EDNA not only detected the known hosts of OFV but also discovered an unknown host leopard plant (Farfugium japonicum), and the possible existence of a new ornamental strain of OFV in nature. Full article

Bovine ephemeral fever is an arthropod-borne viral disease that affects cattle and buffalo in many regions of the world; it causes heavy economic losses in the cattle industry. To date, all BEFV-specific diagnostic molecular assays have been based on the variable glycoprotein (G-protein)-coding genome region, potentially allowing the pathogen to escape detection. We developed two new assays, based on the less variable nucleoprotein genome region, and compared them with two G-protein-based assays. For this comparison, we used 245 samples comprising positive and negative field samples from Israeli outbreaks caused by different strains, belonging to lineage I and IIIa, as well as Australian and Japanese strains (lineages IV and IIIb). The new assays showed high agreement with the previous assay (Kappa = 0.92), detecting 144 out of 147 positive samples (sensitivity of 97.96%), and detected 6 more samples as positive out of 98 samples found negative by the G-protein-based assay. All nine non-agreeing results were validated as positive using a conventional RT-PCR assay. The new assays have higher analytical sensitivity than the previous assays, can be combined with internal controls, and enable the detection of all known BEFVs. The results indicate that these two nucleoprotein-based real-time RT-qPCRs can serve as fast, sensitive, and specific assays for the sustainable detection of BEFV strains. Full article