Archives of Virology最新文献

Porcine parvovirus 5 (PPV5) is an unclassified member of the family Parvoviridae with no reported pathogenicity, although it is associated with multisystemic, reproductive, and respiratory diseases. Its open reading frame 1 (ORF1) encodes non-structural protein 1 (NS1), which is predicted to have helicase activity that is essential for viral replication. This protein contains a C-motif with an invariant asparagine residue that forms the core of the enzyme's active site, in conjunction with the Walker A and B motifs. The aim of this study was the phylogenetic and molecular characterization of the NS1 of PPV5 through nested PCR and sequencing of three Mexican PPV5-positive samples. Subsequently, a phylogenetic tree, identity matrices of nucleotide and amino acid sequences, and a three-dimensional model of NS1 were constructed. The amplified sequences, which represented 96.9% of the PPV5 ORF1, occupied the same branch in the phylogenetic tree and exhibited the most nucleotide sequence similarity to the corresponding region of PPV4 and the most amino acid sequence similarity to the NS1 proteins of PPV4 and PPV6. A three-dimensional model of NS1 displayed a C-motif characteristic of superfamily 3 (SF3) helicases. The phylogenetic proximity of PPV5 to PPV4 and PPV6 suggests that it may belong to the genus Copiparvovirus. Further studies on helicases from viruses infecting domestic animals may be useful in developing antiviral drugs for both human and veterinary medicine.

High-throughput sequencing was used to identify and characterize a novel marafivirus from the weed Leptochloa chinensis, which was tentatively named "Leptochloa chinensis marafivirus" (LcMV). The complete genome of the virus consists of 6,178 base pairs, and its nucleotide sequence is 73.82% identical to that of Sorghum almum marafivirus, which is a member of the genus Marafivirus within the family Tymoviridae. The LcMV genome contains a relatively large open reading frame (ORF) encoding a single polyprotein (220.6 kDa) with five functional domains (methyltransferase, papain-like protease, helicase, RNA-dependent RNA polymerase, and coat proteins), which is a characteristic of members of this genus. Furthermore, a 16-nucleotide conserved marafibox sequence was identified at nucleotide positions 5341–5356. The coat protein of LcMV is 68.02% identical to that of Sorghum almum marafivirus. Phylogenetic analysis based on nucleotide and polyprotein sequences showed that LcMV is closely related to members of the genus Marafivirus. Our findings support the classification of LcMV as a member of a new species within this genus. This is the first report of a marafivirus infecting Leptochloa chinensis, a very important weed of rice.

Tulip mild mottle mosaic disease, caused by tulip mild mottle mosaic virus (TMMMV, species Ophiovirus tulipae), was first reported in Japan in 1979. TMMMV has a negative-sense ssRNA genome and is closely related to ophioviruses such as Mirafiori lettuce big vein virus (MLBVV, Ophiovirus mirafioriense). However, its complete nucleotide sequence has not yet been reported. Therefore, in this study, we determined the complete nucleotide sequences of all four TMMMV segments. The 5′-terminal tetranucleotide sequences were highly conserved, and the five bases at the 5′ end were identical in all segments. Nucleotide sequence comparisons of the four segments showed the highest sequence identity to those of MLBVV (70–76% for the genomic RNA sequences and 81–87% for the amino acid sequences of each ORF, except for ORF2). The amino acid sequences of the coat proteins of TMMMV and MLBVV were found to be 83.1% identical, which is below the 85% threshold for assignment to the same species, indicating that these viruses belong to different species in the same genus.

Human bocaviruses (HBoVs) can cause respiratory illness in young children. Although the first HBoV infection in India was reported in 2010, very little information is available about its prevalence, clinical features, or geographic distribution in this country. This study was conducted using 136 respiratory samples from paediatric patients in a tertiary care hospital in Kerala, 21 of which tested positive for HBoV1 and were further characterized through VP1/VP2 gene sequencing. We found that different strains of HBoV1 are co-circulating in the region and that HBoV1 can be detected in children with severe acute respiratory infections, either alone or coinfections with other pathogens, without any significant differences in their clinical characteristics.

Here, we report the complete genome sequence of a new carlavirus causing mosaic on mint plants in Italy, which we have tentatively named "mint virus C" (MVC). Flexuous particles of around 600 nm were observed using transmission electron microscopy, and next-generation sequencing was performed to determine the nucleotide sequence of the MVC genome, which was found to be 8558 nt long, excluding the poly(A) tail, and shows the typical organization of a carlavirus. The putative proteins encoded by MVC are 44–56% identical to the closest matches in the NCBI database, suggesting that MVC should be considered a member of a new species in the genus Carlavirus. MVC was detected in independent mint samples from different regions of Italy, collected in 2023 and 2024. Two MVC isolates, identified in 2023 (Me1) and in 2024 (Me2), have been included in the Plant Virus Italy (PLAVIT) collection.

A novel capulavirus was identified by high-throughput sequencing in four sugar beet (Beta vulgaris L.) plants collected in April 2023 in Normandy (France). The complete genome of 2744 nucleotides (nt) was sequenced and found to have an organization similar to that of known capulaviruses, with which it showed close phylogenetic relationships. In addition, data mining of a publicly available Thalictrum thalictroides whole-genome shotgun sequence assembly allowed the identification of a contig (JABWDY010003008.1) representing a longer-than-unit length, likely episomal, genome with 99.4% nt sequence identity to the genome of the French beet isolate. The genome of the novel virus shares only 60.7–66.9% nt sequence identity with known capulaviruses, which is well below the species demarcation threshold of 78%, suggesting that a new species should be created to accommodate it. The common name "beet capulavirus 1" (BCV1) is proposed for this novel virus. Given that BCV1 was identified in plants that were coinfected with beet yellows virus, no conclusions can be drawn at this stage about its potential pathogenicity.

Migratory water birds are considered to be carriers of high pathogenicity avian influenza viruses (HPAIVs). In Japan, mallards are often observed during winter, and HPAIV-infected mallards often shed viruses asymptomatically. In this study, we focused on mallards as potential carriers of HPAIVs and investigated whether individual wild mallards are repeatedly infected with HPAIVs and act as HPAIV carriers multiple times within a season. Mallards were experimentally infected with H5N1 and H5N8 HPAIVs that were isolated recently in Japan and phylogenetically belong to different hemagglutinin groups (G2a, G2b, and G2d). All of these strains are more infectious to mallards than to chickens, and the infected mallards shed enough virus to infect others, regardless of whether they exhibited clinical signs. Serum antibodies to the homologous antigen, induced by a single infection with a low virus dose (10 times the 50% mallard infectious dose), were maintained at detectable levels for 84 days. Immunity at 84 days post-inoculation fully protected the mallards from a challenge with the homologous strain, as demonstrated by a lack of viral shedding, and antibody levels did not increase significantly in most of these birds. Protection against heterologous challenge was also observed despite undetectable levels of antibodies to the challenge strain. Our findings suggest that repeated infections with homologous and heterologous HPAIV strains do not occur frequently in individual wild mallards within a season, particularly at low viral doses, and the frequency with which they act as carriers may be limited.

Here, we report the discovery of a new beny-like virus in winter wheat (Triticum aestivum L.) plants collected in the Brittany and Burgundy regions of France in spring 2022, using a high-throughput sequencing approach. A complete genome sequence, comprising two genomic RNAs of 6734 nt (RNA1) and 4856 nt (RNA2) was obtained. This genome shows a typical benyvirus organization, with the RNA1 encoding a large replication-associated protein and the RNA2 encoding, from 5' to 3', the coat protein and its readthrough domain and a triple gene block. Pairwise sequence comparisons and phylogenetic analysis showed that the new virus is a member of the family Benyviridae and that its closest relatives are the recently described beny-like virus wheat stripe mosaic virus and, somewhat more distantly, other recognized benyviruses. Creation of a new species to accommodate the new virus, with the proposed common name "wheat beny-like virus 1" (WBLV1), is suggested, either in the genus Benyvirus or in another genus to be created within the family Benyviridae. Given that WBLV1 was identified in plants that were coinfected by other viruses, no conclusions can be drawn at this stage on its potential pathogenicity.

Pakistan has experienced a total of six COVID-19 waves throughout the pandemic, each driven by distinct SARS-CoV-2 lineages. This study explores the introduction of Omicron lineage BA.4 into Pakistan, which contributed to the sixth wave between June and September 2022. A discrete phylogeographic reconstruction was conducted on a global dataset of 443 samples across 49 countries, of which 92 samples were collected in Pakistan. Samples collected in Pakistan were from 10 locations across the country: Balochistan, Gilgit Baltistan, Islamabad, Jhelum, Karachi, Khyber Pakhtunkhwa, Lahore, Mirpur, Punjab, and Swat. This analysis identified eight distinct introductions into Pakistan between May 2022 and January 2023. The majority of BA.4 cases in Pakistan descended from one introduction, indicating that most transmission occurred within the country rather than through multiple importations. Two exportation events were also identified. During this time, there were reduced public health interventions in place, following the lifting of international travel restrictions in March 2022. This work stems from a collaboration between the UKHSA New Variant Assessment Platform and the National Institute of Health of Pakistan to strengthen genomic surveillance in front-line public health laboratories for global pandemic preparedness and response. The benefit of such partnerships has been evidenced throughout the COVID-19 pandemic, where scientific collaboration through data sharing and knowledge exchange has facilitated risk assessment and action. As a result of this collaboration, we have conducted the first Bayesian phylodynamic analysis of SARS-CoV-2 in Pakistan. This work can lend evidence to support understanding of SARS-CoV-2 variant transmission patterns and inform public health containment measures for virus spread.