Archives of Virology最新文献

In this study, we investigated infectious canine hepatitis (ICH), caused by canine adenovirus 1 (CAdV-1), in 125 bear carcasses submitted for examination. CAdV-1 is known to cause severe disease in domestic dogs and in wild canids and bears. Using molecular and/or histopathological methods, CAdV-1 infection was confirmed in 12 cases: 11 in sloth bears (Melursus ursinus) and one in an Asiatic black bear (Ursus thibetanus). Affected captive bears exhibited acute onset of high fever, jaundice, bloody vomitus, and foul-smelling diarrhoea, followed by death. Necropsy revealed widespread congestion and petechial-to-ecchymotic haemorrhages across multiple visceral organs. Histopathological examination showed marked vascular changes, including engorged blood vessels, oedema, and haemorrhages. Intranuclear basophilic inclusion bodies were observed in endothelial cells, hepatocytes, and Kupffer cells. Immunohistochemistry confirmed the presence of CAdV-1 antigen in endothelial cells of various organs, as well as in hepatocytes and Kupffer cells in the liver. Molecular analysis identified a strain closely related to CAdV-1 isolates previously reported in domestic dogs and other carnivores in various parts of the world. The virus was successfully isolated in MDCK cells from sloth bear samples. Among 99 live sloth bears tested, 41.4% were seropositive for CAdV-1 antibodies. Our findings confirm the susceptibility of these bear species to CAdV-1 and highlight the need for ongoing surveillance, as well as the importance of vaccination in captive bear populations to prevent the spread of this disease.

Tomato spotted wilt virus (TSWV) is a harmful pathogen that causes severe disease in tomato, pepper, and other horticultural and agronomic crops. Its genome comprises three linear single-stranded RNA molecules (segments L, M, and S), which are unequally packed in nucleocapsids. Although its genome structure and molecular mechanism of infection are well understood, the evolutionary dynamics of this virus require further analysis to determine the most probable viral ancestor, the date of divergence, the ancestral geographical source of dispersal, and the demographic history of TSWV. For this, we employed a Bayesian framework to analyze whole-genome sequences of 136 isolates of TSWV obtained from different sites worldwide with a sampling window of 35 years, and phylodynamic analysis was performed separately for segments L, M, and S. Our results showed that the mutation rates of the different genome segments ranged from 1.678 × 10^− 4 to 2.444 × 10^− 4 substitutions/site/year. Although the estimated time to the most recent common ancestor varied depending on the dataset used, the most probable date of TSWV divergence was around 1768 CE. Our phylogeographic analysis yielded concordant results for the three genome segments, indicating that the TSWV population originated in South Korea and, from there, first expanded to Europe and then to North America and other continents. Past population dynamics analysis showed that the virus experienced two major population expansions that coincided with the expansion of the agricultural frontier and the emergence of new species of insect vectors.

To enhance preparedness against existing and new zoonotic viruses such as Hendra virus, Nipah virus, and other paramyxoviruses, screening tools and efficient diagnostic methods are needed. Here, we established a conventional nested pan-PCR assay using previously described primers for screening of human and bat samples. Additionally, we developed specific real-time RT-PCR (RT-qPCR) assays to detect Nipah virus and Hendra virus genotypes 1 and 2. Both PCR methods demonstrated good performance and could be used for screening of paramyxoviruses. Human serum and cerebrospinal fluid samples from 558 Finnish patients and 60 serum samples from Kenyan patients were screened using the nested-pan-PCR assay, and all were negative. In addition, we screened 340 synanthropic bat samples collected during 2021 and 2023 from Kenya, resulting in the discovery of two parajeilongviruses in Angolan free-tailed bat (Mops condylurus) samples.

A new double-stranded RNA mycovirus, tentatively named "Sclerotinia sclerotiorum victorivirus 2" (SsVV2), was isolated from Sclerotinia sclerotiorum strain DT-110. The complete genome of SsVV2 is 5135 nucleotides in length and contains two open reading frames (ORF1 and ORF2) that overlap at the tetranucleotide AUGA (positions 2546-2549). ORF1 and ORF2 were predicted to encode a coat protein (CP, 755 amino acids) and an RNA-dependent RNA polymerase (RdRP, 836 amino acids), respectively. BLASTp analysis identified Sclerotinia nivalis victorivirus 1 (SnVV1) as the closest match to SsVV2, with their RdRPs sharing 75.7% amino acid sequence identity. Phylogenetic analysis based on the RdRP and CP of victoriviruses further support the clustering of SsVV2 with SnVV1. These results confirm that SsVV2 as a new member of the species Victorivirus nijyusani, genus Victorivirus, family Pseudototiviridae.

Alternaria alternata orfanplasmovirus 1 (AaOrfV1), a previously unreported orfanplasmovirus, was discovered in strain TG155-3 of Alternaria alternata f. sp. mali in this study. The genome of AaOrfV1 consists of two positive-sense single-stranded RNA segments. RNA1, which is 3122 nucleotides in length, encodes a protein with 973 amino acids. BLASTp analysis showed that this protein had the highest sequence similarity (62.79% identity) to the RNA-dependent RNA polymerase of downy mildew lesion associated orfanplasmovirus 4. RNA2, with a length of 2,485 nucleotides, encodes a protein with 785 amino acids that showed the highest similarity (44.02% identity) to a hypothetical protein of downy mildew lesion associated orfanplasmovirus 7. Phylogenetic analysis indicated that AaOrfV1 clusters with other reported orfanplasmoviruses, supporting its classification as a new member of the proposed family "Orfanplasmoviridae". This is the first report of the complete genome sequence of an orfanplasmovirus from Alternaria alternata f. sp. mali. These findings significantly enhance our understanding of orfanplasmoviruses and the diversity of mycoviruses in A. alternata.

Multidrug-resistant Klebsiella pneumoniae requires alternative therapies. In this study, we characterized two novel phages, PKP K9 (a siphovirus) and PKP Kh11 (a myovirus). Both showed genomic safety and exhibited excellent reproduction and physicochemical tolerance. A cocktail containing both phages had a broad combined host range (85.7%, 72/84) and showed potent in vitro activity with distinct dose-dependent inhibition modes. In a Galleria mellonella infection model, each phage individually and the two combined provided complete prophylactic and therapeutic protection against lethal challenge. The PKP K9/PKP Kh11 cocktail demonstrates significant therapeutic potential against multidrug-resistant K. pneumoniae.

The order Martellivirales currently comprises seven families of positive-strand (+) RNA viruses, namely, Bromoviridae, Closteroviridae, Endornaviridae, Kitaviridae, Mayoviridae, Togaviridae, and Virgaviridae, that infect a range of animals, fungi, and plants. These viruses display remarkably diverse virions built from non-homologous capsid proteins but are unified through homologous alphavirus-like replication module. Here, we introduce an additional family in the order Martellivirales, with the proposed name “Tobaliviridae”, to accommodate an emerging group of viruses reported from fungi. This family includes a single genus, “Tobalivirus”, with nine species. Tobaliviruses share a capsid protein homologous to those of closteroviruses, potyviruses and alphaflexiviruses, and consistently, some members of the family have been demonstrated to form flexible filamentous virions. The formal taxonomic proposal for the establishment of the family “Tobaliviridae” is awaiting ratification by the International Committee for Taxonomy of Viruses (ICTV).

A novel virus belonging to the genus Victorivirus was identified in the plant-pathogenic fungus Colletotrichum gloeosporioides. Its genome is a double-stranded RNA molecule of 5217 bp containing two open reading frames (ORFs). The 5′-proximal ORF (ORF1) encodes a coat protein (CP) consisting of 734 amino acids (aa), whereas the 3′-proximal ORF (ORF2) encodes an RNA-dependent RNA polymerase (RdRp) of 875 aa. The two ORFs overlap at the tetranucleotide sequence AUGA, facilitating a coupled termination–initiation mechanism, which is characteristic of members of the genus Victorivirus. The amino acid sequences of RdRp and CP were found to be most similar (42% and 34% identical, respectively) to those of the Ustilaginoidea virens RNA virus 1. Phylogenetic analysis based on RdRp and CP sequences further supported the placement of this virus within the genus Victorivirus. The genome of this victorivirus, for which we propose the name “Colletotrichum gloeosporioides victorivirus 1” (CgVV1), is 5.2 kb in length and was one of several dsRNA segments identified in the fungal isolate, indicating coinfection with other mycoviruses. To the best of our knowledge, this is the first report of a victorivirus infecting C. gloeosporioides.

In conventional medicinal systems, Ocimum basilicum (OB) is known to be effective against viral infections. A thorough screening of OB's phytoconstituents against Japanese encephalitis virus (JEV) in an in silico and in vitro model has not been documented. Therefore, we used Schrödinger software to do a virtual screening and molecular dynamics simulation (MDS) (100 ns) on 265 phytocompounds from OB against the envelope (E) protein (PDB ID: 3P54) of JEV. Chicoric acid (CA), rutin, and salvianolic acid A (SAA) complexes with the E protein showed outstanding docking scores of -9.136, -9.135, and − 11.838 (kcal/mol), which were all higher than that obtained with the reference compound mycophenolate (-4.481) (kcal/mol). MDS analysis revealed that these compounds, especially CA and rutin, showed comparatively strong stability in the binding pocket of the protein. CA and rutin also exhibited lower binding free energy with this protein than the standard. Moreover, principal component and free energy landscape analysis highlighted the antiviral potential of these compounds against JEV. In vitro experiments demonstrated the antiviral potential of CA and rutin at the early stage of the viral life cycle. These drugs also reduced the levels of proinflammatory cytokines (TNF-α and IL-6) and reactive oxygen species in JEV-infected cells. This study provides insight into the therapeutic potential of CA and rutin as novel drugs against JEV. Additional study is needed to validate their antiviral and neuroprotective activity in an in vivo model of JE.

In China, inpatient/outpatient visits for rotavirus (RV)-associated diarrhea are common among children aged < 5 years. An interim analysis evaluated RV genotype circulation in China in an ongoing observational effectiveness study of a pentavalent (RV5) vaccine. Data were collected (October 2020-March 2021) from children eligible for vaccination with three doses of RV5 and receiving treatment for acute gastroenteritis. RV gastroenteritis was reported in 494 (62.1%) of the 796 children tested (median age, 15 months). The circulating genotypes were G9 (81.8%), G2 (5.5%), G8 (4.6%), and G3 (0.4%); no G1 or G4 genotypes were detected. The most common genotype combinations were G9P[8] and G2P[4].