Acta virologica最新文献

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the associated disease Coronavirus disease 2019 (COVID-19) continues to spread throughout the world, causing millions of infections and dead. One major question in predicting the course of the COVID-19 pandemic is how well and how long the immune response protects the host from reinfection. Although more studies are needed, evidence suggests that virus-specific B cell response in people with SARS-CoV-2 infection is rapidly generated and seems to be more reliable marker of long-lasting humoral responses than serum antibodies. Here we reviewed all related major studies of immune response to SARS-CoV-2 virus to better understand the natural protection against the virus, and the risk of reinfection. The ability of our community to eradicate this virus will mostly depend on our knowledge of the immune response, critical not only for vaccine development and distribution but also for therapeutic options. Keywords: SARS-CoV-2 virus reinfection; humoral immune response; SARS-CoV-2 virus variants; vaccination.

Cross-sectional seroprevalence study of SARS-CoV-2 IgG antibodies was accomplished in the Slovak Academy of Sciences to inform authorities of research institutions about the situation at their workplaces, to assess the risk of next exposure to SARS-CoV-2, and to guide decisions on institutional measures sustaining essential research in evolving epidemic situation. Study participants provided informed consent, anamnestic information, and self-collected dry blood spot samples that were analyzed by ELISA for SARS-CoV-2 S protein-specific IgG antibodies. Relative antibody levels detected in 1928 subjects showed seroprevalence of 84.13% and led to the following main findings consistent with the current knowledge: (1) mRNA-based vaccines induce better humoral response compared to adenovirus vaccines, (2) antibody levels reflect severity of COVID-19 symptoms, (3) post-COVID vaccination results in marked elevation of IgG levels particularly in asymptomatic and mild cases, (4) antibody levels decrease with increasing time elapsed from vaccination or COVID-19. In addition, data sorting to distinct research institutes and their clustering to three principal scientific sections of the Slovak Academy of Sciences revealed marked differences in seroprevalence, and allowed to identify workplaces with relatively high seropositivity and response rate that can potentially provide a safer working environment than those, where seroprevalence was low or unknown due to low participation. Thus, findings of this study can have direct implications on management decisions during the next pandemic development, with the necessity to keep in mind the phenomenon of time-dependent immunity waning and current spread of more contagious Delta variant of SARS-CoV-2. Keywords: SARS-CoV-2 coronavirus; COVID-19; spike protein; seroprevalence; antibodies; vaccination.

Feline calicivirus (FCV) is a common cause of upper respiratory tract disease in cats. In this study, the complete genome sequence of FCV 14Q315, which was detected from a dead domestic cat with a hemorrhagic-like disease, was analyzed to identify the genetic characteristics. The FCV 14Q315 genome was 7,684 bp. Phylogenetic analyses based on the ORF1, ORF2, and ORF3 sequences indicated that FCV 14Q315 is more closely related to FCV 15D022 than to other FCV strains. ORF1 of FCV 14Q315 shared high sequence similarity with ORF1 of FCVs 15D022 and UTCVM-H1. We further evaluated genetic recombination in ORF1 of FCV 14Q315 and detected intergenic recombination between p30 and the ORF1/ORF2 junction with high significance. Particularly, the non-recombination region in ORF1 of FCV 14Q315 showed high sequence similarity with FCVs GX2019, CH-JL2, and 15D022. The recombination region in ORF1 of FCV 14Q315 showed the highest similarity with FCV UTCVM-H1, which is associated with a hemorrhagic-like disease. The results suggest that the UTCVM-H1-like FCV was introduced into the Republic of Korea and presumably recombined with Korean FCVs by occasional mixed infections. In addition, the Korean FCV strains were located in several phylogenetic clusters with marked genetic diversity in the ORF2 region. These results imply that Korean FCVs possess high genetic diversity owing to mutations and recombination. Furthermore, it is possible that certain FCVs caused cyclical infections in the Korean cat population based on a phylogenetic analysis of FCVs isolated at different time points. Keywords: calicivirus; virulent systemic feline calicivirus; recombination; hemorrhagic-like disease.

Gerbera is the most popular cut flower known for its variety of colors and is grown across the world. Its production is challenged by numerous diseases affecting production and quality. During our survey, ten samples from the gerbera plants exhibiting phyllody disease symptoms were collected from Bangalore Rural District, Karnataka, India. The association of phytoplasma with the gerbera phyllody samples was confirmed by PCR using 16SrRNA, SecY, Ribosomal protein (rp) and SecA gene-specific primers. PCR products were amplified from all ten gerbera plants using phytoplasma-specific primers. The amplified PCR products were cloned and sequenced; the sequences of the ten clones were identical. Therefore, representative isolate (GePP1, Gerbera phyllody phytoplasma) was selected for further analysis. The sequence analysis showed that GePP1 shared maximum nucleotide (nt) identity of 97.1% (16SrRNA) with Eggplant big bud, 98.7 to 98.8% (SecY gene) with Tomato big bud, 99.2 to 99.6% (rp gene) with Alfalfa witches-broom (EF193371) and 99.1% (SecA gene) with Sesame phyllody phytoplasmas and that it belongs to the Ca. P. aurantifolia (16SrII) group. This result was well supported by the phylogenetic analysis showing GePP1 (16Sr RNA, SecY, rp and SecA genes) closely clustering with the Ca. P. aurantifolia 16SrII group isolates reported so far. The virtual RFLP pattern generated for the phytoplasma from gerbera was different (similarity coefficient 0.89) from the reference pattern of Ca. P. aurantifolia (16Sr II) subgroup after analysis with four enzymes (BfaI, Hha1, Sau3AI and RsaI). Based on the threshold similarity coefficient for a new subgroup (delineation should be set at 0.97), the GePP1 may be considered as new subgroup of Ca. P. aurantifolia (16SrII) group. This is the first report of Ca. P. aurantifolia belonging to 16Sr II group affecting gerbera in India. Keywords: Candidatus Phytoplasma aurantifolia; phyllody; gerbera; PCR; phylogenetic analysis.

Nora virus is a RNA picorna-like virus that produces a persistent infection in Drosophila melanogaster. The genome is approximately 12,300 bases and is divided into four open reading frames (ORFs). Structurally, there are four important viral proteins: VP3, VP4A, VP4B, and VP4C. Three proteins (VP4A, VP4B, and VP4C) that form the virion's capsid are encoded by ORF 4, which produces a polyprotein that is post-translationally cleaved. The fourth protein (VP3) is encoded by ORF 3 and it is hypothesized to play a role in virion stability. The genes for these proteins were individually cloned into Escherichia coli, expressed, and the proteins were purified. Virus-like particles (VLPs) were assembled in vitro by mixing the proteins together in different combinations and measured via electron microscopy. Assemblies that contained VP4A and/or VP3 created VLPs with similar sizes to purified empty Nora virus capsids, potentially indicating that VP4A and/or VP3 are vital for Nora virus capsid structure, assembly, and/or stability. Not only does this study provide insight into the role of Nora virus proteins, but it may also lead to a deeper understanding of how Nora virus or other picorna-like viruses undergo assembly.  Keywords: RNA viruses; Nora virus; picorna-like virus; virus-like particles; capsid assembly.

Proteomics is widely used to investigate and understand viral infections in livestock and poultry. The effects of infections on abundance, post-translational modifications, and interactions of host cell proteins have been systematically studied using proteomic methods, such as two-dimensional electrophoresis and mass spectrometry. Such research increases our understanding of the pathogenesis of viral infections and contributes to the development of novel anti-viral drugs for the livestock and poultry industries. Keywords: proteomics; infectious diseases; poultry and livestock; application.

The effects of double combinations of enterovirus (EV) replication inhibitors against Coxsackieviruses B1 (neurotropic Connecticut-5 strain) and B3 (cardiotropic Woodruff and neurotropic Nancy strains) were tested in cell culture experiments. Compounds with different mechanisms of action were studied: pleconaril, guanidine.HCl, MDL-860 and oxoglaucine. A three-dimensional method was applied for determining the character of the combined effect. The study determined several synergistic double combinations: guanidine.HCL + pleconaril or MDL-860 against Coxsackievirus B1; MDL-860 + each of the other EV replication inhibitors and guanidine.HCl + pleconaril against the cardiotropic Woodruff strain of Coxsackievirus B3; MDL-860 + oxoglaucine against the neurotropic Nancy strain of Coxsackievirus B3. No increased cytotoxicity was manifested in any of the tested double combinations. Keywords: antivirals; combination activity; Coxsackieviruses.

Daphnia pulex from a small pond were infected by an iridescence virus. Infected daphnia differed from healthy ones due to the intense characteristic pink reflected iridescent color. Infected individuals collected in the field died in laboratory as a result of the iridoviral infection. Ultrastructural analysis using electron microscopy revealed highly abundant icosahedral virions in the cytoplasm of multiple types of tissue in the infected daphnids. The mean particle sizes were approximately 200 nm (n = 150) edge-to-edge and 185 nm point-to-point. Keywords: daphnia; Daphnia pulex; iridovirus; electron microscopy.

Coronavirus infection is now the leading cause of death globally. Despite the several bedsides- to- bench investigations carried out by researchers all over the world to identify the best prophylactic and therapeutic options for this deadly virus, no novel vaccine or treatment drug has been developed. Accumulating evidence suggests that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with hyper inflammation characterized by excessive release of pro-inflammatory cytokines known as a cytokine storm. The hallmark of this unregulated inflammatory response includes viral sepsis, pneumonitis shock, coagulopathy, and acute respiratory distress syndrome (ARDS) which is the major cause of death in COVID-19 patients. In the midst of cytokine storm and coagulopathy, anti-viral agents alone will not provide the much-needed therapeutic effect. Hence, the need to combine anti-inflammatory agents such as interferons, angiotensinogen converting enzyme 2 (ACE-2) inhibitors, interleukin 6 (IL-6), and Janus kinase (JAK) family inhibitors, anticoagulants and other agents involved in inflammation resolution. This review critically presented a comprehensive overview of SAR-CoV-2, unveiled the mechanisms of the inflammatory response in SARS-CoV-2 and also highlighted possible specific prophylactic and therapeutic interventions that will circumvent inflammatory induced deaths in COVID-19 patients. Keywords: COVID-19; SARS-CoV-2; cytokine storm; coagulopathy and anti-inflammatory.

Coronavirus disease 2019 (COVID-19) is a severe acute respiratory syndrome caused by a novel strain of coronavirus (SARS-CoV-2) which was declared by WHO as a cause of global pandemic. By human-to-human transmission it caused severe damage to mankind with increased mortality rate worldwide. Coronavirus is a spherical enveloped virus with single stranded positive-sense RNA with a size of ~30 kilobases encoding various structural, non-structural and accessory proteins. The entry of coronavirus into the host cells is mediated by spike proteins. SARS-CoV-2 efficiently replicates in host cell and by evading immune surveillance, like innate and adaptive immune responses, in the host cells ultimately leads to increased virulence and disease outcome. In the current review, we highlighted the molecular insights of SARS-CoV-2 and its infection mechanism in the host cell via host-viral protein interactions based on currently available data up to 16thMay 2020 using various research literature databases. The diagnostics of SARS-CoV-2 is mainly done by RT-qPCR and serological tests. There is no effective treatment for COVID-19, however, few methods like plasma therapy and remdesivir treatment are reported to show promising results in improving patient's health and decreasing mortality rate. Keywords: SARS-CoV; spike protein; nucleocapsid; COVID-19; interferon.