Archives of Virology最新文献

The genus Viburnum includes more than 150 species of ornamental shrubs and trees that are cultivated worldwide. In Aotearoa New Zealand (NZ), V. opulus is the most popular of the species widely used in landscaping. To date, alfalfa mosaic virus (AMV) has been the only virus reported in viburnum in NZ. Here, we report the identification and molecular characterization of a novel carlavirus, tentatively named "viburnum carlavirus 1" (VibCV1), from a V. opulus plant coinfected with AMV. The virus was characterized using high-throughput sequencing, transmission electron microscopy, and herbaceous indexing. The complete genome of VibCV1 is 8,444 nucleotides in length and contains six open reading frames, with an organization typical of members of the genus Carlavirus. Phylogenetic analysis revealed that VibCV1 is most closely related to helleborus mosaic virus (HeMV), sharing 80.24% and 85.48% amino acid sequence identity in the replicase and coat protein, respectively. These values lie on the borderline of the current species demarcation criteria for the family Betaflexiviridae. Considering its distinct natural host range, limited distribution, and phylogenetic divergence from HeMV, we suggest that VibCV1 possibly represents a new species within the genus Carlavirus. The low incidence of VibCV1 in NZ viburnum populations is also discussed.

The genus Alphanucleorhabdovirus comprises plant-infecting viruses with an unsegmented, negative-sense, single-stranded RNA genome. Here, we report the complete genome sequence of a novel alphanucleorhabdovirus infecting cassava (Manihot esculenta Crantz), identified in accession BGM-1275 from the germplasm collection at Embrapa Mandioca e Fruticultura (Cruz das Almas, Bahia, Brazil). The viral genome is 13,625 nucleotides (nt) in length and displays the typical organization of alphanucleorhabdoviruses, with six predicted open reading frames. Pairwise comparisons of its whole genome sequence with those of other known alphanucleorhabdoviruses revealed nt sequence identity values in the range of 31.0-67.8%, which is below the species demarcation threshold (75%). Phylogenetic analysis based on the L gene confirmed placement of the novel virus within the genus Alphanucleorhabdovirus, with cassava alphanucleorhabdovirus 1 as the closest relative. Reverse transcription polymerase chain reaction assays detected the virus in symptomatic (cassava frogskin disease) and asymptomatic cassava samples collected in fields in Northeast Brazil (Paraíba and Rio Grande do Norte) and in other Embrapa accessions, suggesting widespread occurrence. The name “cassava alphanucleorhabdovirus 2” (CsRV2) is proposed for the newly discovered virus.

The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) is a critically endangered freshwater cetacean that is endemic to China. In this study, we conducted viromic analysis on swab and tissue samples from three stranded individuals collected in 2024, using high-throughput meta-transcriptomic sequencing. A diverse range of viral sequences was identified, including a large proportion of unclassified viruses, bacteriophage-related viruses, and vertebrate-associated viruses. Notably, we assembled the complete genome sequence of a novel papillomavirus, designated Neophocaena asiaeorientalis papillomavirus isolate WH240216 (NasiPV-WH240216), which shares 82.2% overall nucleotide sequence identity and 87.5% L1 gene identity with Phocoena spinipinnis papillomavirus 1 (PsPV1). The genome is 8,010 bp in length and exhibits the typical genome organization and conserved protein motifs of a papillomavirus. Phylogenetic analysis placed this virus within the genus Omikronpapillomavirus, and its sequence divergence met the ICTV criteria for a novel papillomavirus type. These findings expand our knowledge of the diversity of papillomaviruses in cetaceans and provide important insights into the evolution and potential pathogenicity of marine mammal papillomaviruses.

Human cytomegalovirus (HCMV) is a betaherpesvirus that has evolved multiple defense mechanisms against host immunity. Most HCMV infections go unnoticed, but the reactivation of the latent virus can be life-threatening in immune-suppressed people. Over millions of years of coevolution with the human host, HCMV has adapted to evade both innate and adaptive immune responses through a dynamic host-pathogen arms race in which selective pressures from host immunity have driven the diversification and refinement of viral genes. This is particularly evident in the UL and US regions of the HCMV genome, which encode multiple proteins that interfere with antigen presentation and modulate immune receptor signaling. HCMV also employs molecular mimicry, encoding an MHC class I homolog, UL18, which binds to LIR-1 to inhibit NK cell activation, enabling immune evasion and persistent infection. This mini-review focuses on the key immunoevasive mechanisms by which HCMV gene products interfere with NK and T cell recognition and effector functions to modulate host immune responses. Elucidating these strategies is critical for identifying novel antiviral targets and informing the rational design of effective vaccines.

BlD-PLA₂, a phospholipase A₂ isolated from Bothrops leucurus venom, exhibited notable antiviral activity against dengue virus (DENV) in vitro. Treatment significantly reduced viral RNA levels, particularly when administered during the infection period, suggesting interference with early stages of viral entry. Immunofluorescence and ELISA assays confirmed its interaction with host cell components. Importantly, reseeding assays demonstrated that residual viral RNA detected after treatment was not associated with infectious particles. These findings indicate that BlD-PLA₂ effectively disrupts DENV infection and support its potential as a lead compound for the development of novel antiviral strategies. 

Worldwide, 50 million people are chronically infected with hepatitis C virus (HCV), with 1 million new infections annually. The limitations of direct-acting antiviral drugs, including high costs, limited access, reinfections, and emergence of drug resistance, have highlighted the urgent need for a prophylactic vaccine to achieve global elimination. However, the development of an HCV vaccine remains challenging due to the genetic diversity of the virus, evasion mechanisms, and our limited understanding of protective immunity. The use of DNA-based vaccines is a promising strategy for HCV vaccine development due to their safety, stability, low production cost, scalability, and the capacity to incorporate multiple antigens. In this study, we evaluated the immunogenicity of a DNA-based vaccine, pCE1E2, which encodes the HCV core, envelope 1 (E1), and envelope 2 (E2) proteins and produces virus-like particles (VLPs). Subcutaneous vaccination of BALB/c mice with pCE1E2 in combination with Freund’s adjuvant induced the production of specific antibodies against the HCV core and envelope proteins, indicating the stimulation of a strong humoral immune response. In addition, activation of B and T cells was observed in liver and spleen tissues, suggesting cellular immune responses. These results highlight the immunogenic potential of the pCE1E2 DNA vaccine for induction of effective immunity against HCV. Future studies will focus on studying specific cellular responses to the vaccine and exploring alternative adjuvants, routes of administration, and cross-genotype neutralization.

Sweet potato (Ipomoea batatas [L.] Lam.), an important food crop, is extensively cultivated in more than 100 countries and regions worldwide, particularly in developing countries. In this study, a novel RNA virus, tentatively named "sweet potato virus H" (SPVH), with the proposed species name "Potyvirus hebatatae", was identified in Hainan, China. Its complete genomic sequence was obtained through small-RNA sequencing (sRNA-seq) technology and RT-PCR. The viral genome is 10,901 nt in length (excluding the 3'-terminal poly(A) tail) and encodes a putative polyprotein of 3,498 amino acids. The genomic structure of SPVH is similar to that of sweet potato feathery mottle virus (SPFMV). The cleavage sites and conserved motifs of the SVPH polyprotein were analyzed, and the nucleotide and amino acid sequences were compared with those of other SPFMV subgroup viruses. Pairwise comparisons revealed that the complete genome of SPVH shared 64.2–68.4% nucleotide sequence identity and the polyprotein shared 66.7–71.8% amino acid sequence identity with other SPFMV subgroup viruses (NC001841, NC014742, NC017970, NC018093, and MH388502). Phylogenetic analysis showed that SPVH was grouped into a separate branch closer to SPFMV and sweet potato virus C (SPVC) within the potyvirus subgroup. These results suggest that SPVH is a new member of the genus Potyvirus.

Millingtonia hortensis is a species of medium-to-large trees with scented flowers that are grown along avenues and in parks in tropical and subtropical regions. In the present study, we report a mosaic disease of M. hortensis in Telangana, India, and the identification of an associated novel begomovirus, which we have tentatively named "Millingtonia mosaic virus" (MilMV). The monopartite genome of MilMV is 2,743 nt long and contains nine ORFs – three in the viral sense strand (V1-V3) and six in the antisense strand (C1-C6). Genome sequence comparisons revealed that this virus is most similar (89.2% sequence identity) to an isolate of chilli leaf curl India virus (ChiLCINV). This sequence identity value is below the species demarcation threshold for the genus Begomovirus. Phylogenetic analysis showed that MilMV belongs to a distinct subclade that also includes ChiLCINV. Recombination analysis identified a putative recombination event in the genome involving a papaya leaf curl virus isolate as the minor parent. The study provides a basis for further studies investigating the transmission and biological properties of MilMV.

Background Single-stranded RNA viruses such as the Crimean-Congo hemorrhagic fever virus (CCHFV) exhibit a high degree of genetic diversity that can result in the emergence of new viral quasispecies. The aim of this study was to examine the kinetics of CCHFV replication and to identify genetic variations resulting from serial passage in susceptible cell lines that could potentially affect the infectivity and fitness of laboratory virus strains. As efficacy studies of candidate therapeutics and vaccines rely on well-characterized virus stocks, mutations emerging due to virus propagation might result in inaccurate test results. Methods Viral growth kinetics were examined in four cell lines (Vero E6, Vero, SW13, and BHK-21), using different multiplicity-of-infection values. After 10 rounds of serial passaging and cross-passaging, whole-genome sequencing and bioinformatic analysis were performed to map growth-adaptive signature mutations. Results All four cell lines were found to be susceptible to CCHFV infection, and permissivity increased during serial passaging in Vero and BHK-21 cells. Mutations emerged in a cell-line-specific manner, and the particular cell line used for virus propagation had a significant effect on the mutation frequency, especially in the L segment. Conclusions By mapping mutations that occurred during serial passage, we were able to observe viral evolution in a controlled laboratory setting, as well as the accompanying phenotypic changes. Our results provide information about how CCHFV adapts to commonly used cell lines that might be applied for the development of diagnostic tests, antiviral drugs, and vaccines.