Viral Dissemination Research Articles

Dual Role of Extracellular Vesicles as Orchestrators of Emerging and Reemerging Virus Infections.

Current decade witnessed the emergence and re-emergence of many viruses, which affected public health significantly. Viruses mainly utilize host cell machinery to promote its growth, and spread of these diseases. Numerous factors influence virus-host cell interactions, of which extracellular vesicles play an important role, where they transfer information both locally and distally by enclosing viral and host-derived proteins and RNAs as their cargo. Thus, they play a dual role in mediating virus infections by promoting virus dissemination and evoking immune responses in host organisms. Moreover, it acts as a double-edged sword during these infections. Advances in extracellular vesicles regulating emerging and reemerging virus infections, particularly in the context of SARS-CoV-2, Dengue, Ebola, Zika, Chikungunya, West Nile, and Japanese Encephalitis viruses are discussed in this review.

Phylogenetic evidence of extensive spatial mixing of diverse HIV-1 group M lineages within Cameroon but not between its neighbours.

From the perspective of developing relevant interventions for treating HIV and controlling its spread, it is particularly important to comprehensively understand the underlying diversity of the virus, especially in countries where the virus has been present and evolving since the cross-species transmission event that triggered the global pandemic. Here, we generate and phylogenetically analyse sequences derived from the gag-protease (2010 bp; n = 115), partial integrase (345 bp; n = 36), and nef (719 bp; n = 321) genes of HIV-1 group M (HIV-1M) isolates sampled between 2000 and 2022 from two cosmopolitan cities and 40 remote villages of Cameroon. While 52.4% of all sequenced viruses belonged to circulating recombinant form (CRF) 02_AG (CRF02_AG), the remainder were highly diverse, collectively representing seven subtypes and sub-subtypes, eight CRFs, and 36 highly divergent lineages that fall outside the established HIV-1M classification. Additionally, in 77 samples for which at least two genes were typed, 31% of the studied viruses apparently had fragments from viruses belonging to different clades. Furthermore, we found that the distribution of HIV-1M populations is similar between different regions of Cameroon. In contrast, HIV-1M demographics in Cameroon differ significantly from those in its neighbouring countries in the Congo Basin (CB). In phylogenetic trees, viral sequences cluster according to the countries where they were sampled, suggesting that while there are minimal geographical or social barriers to viral dissemination throughout Cameroon, there is strongly impeded dispersal of HIV-1M lineages between Cameroon and other locations of the CB. This suggests that the apparent stability of highly diverse Cameroonian HIV-1M populations may be attributable to the extensive mixing of human populations within the country and the concomitant trans-national movements of major lineages with very similar degrees of fitness; coupled with the relatively infrequent inter-national transmission of these lineages from neighbouring countries in the CB.

The resurgence of influenza A/H3N2 virus in Australia after the relaxation of COVID-19 restrictions during the 2022 season.

This study retrospectively analyzed the genetic characteristics of influenza A H3N2 (A/H3N2) viruses circulating in New South Wales (NSW), the Australian state with the highest number of influenza cases in 2022, and explored the phylodynamics of A/H3N2 transmission within Australia during this period. Sequencing was performed on 217 archived specimens, and A/H3N2 evolution and spread within Australia were analyzed using phylogenetic and phylodynamic methods. Hemagglutinin genes of all analyzed NSW viruses belonged to subclade 3C.2a1b.2a.2 and clustered together with the 2022 vaccine strain. Complete genome analysis of NSW viruses revealed highly frequent interclade reassortments between subclades 3C.2a1b.2a.2 and 3C.2a1b.1a. The estimated earliest introduction time of the dominant subgroup 3C.2a1b.2a.2a.1 in Australia was February 22, 2022 (95% highest posterior density: December 19, 2021-March 13, 2022), following the easing of Australian travel restrictions, suggesting a possible international source. Phylogeographic analysis revealed that Victoria drove the transmission of A/H3N2 viruses across the country during this season, while NSW did not have a dominant role in viral dissemination to other regions. This study highlights the importance of continuous surveillance and genomic characterization of influenza viruses in the postpandemic era, which can inform public health decision-making and enable early detection of novel strains with pandemic potential.

Chikungunya Virus RNA Secondary Structures Impact Defective Viral Genome Production.

Chikungunya virus (CHIKV) is a mosquito-borne RNA virus that poses an emerging threat to humans. In a manner similar to other RNA viruses, CHIKV encodes an error-prone RNA polymerase which, in addition to producing full-length genomes, gives rise to truncated, non-functional genomes, which have been coined defective viral genomes (DVGs). DVGs have been intensively studied in the context of therapy, as they can inhibit viral replication and dissemination in their hosts. In this work, we interrogate the influence of viral RNA secondary structures on the production of CHIKV DVGs. We experimentally map RNA secondary structures of the CHIKV genome using selective 2'-hydroxyl acylation analyzed by primer extension and mutational profiling (SHAPE-MaP), which couples chemical labelling with next-generation sequencing. We correlate the inferred secondary structure with preferred deletion sites of CHIKV DVGs. We document an increased probability of DVG generation with truncations at unpaired nucleotides within the secondary structure. We then generated a CHIKV mutant bearing synonymous changes at the nucleotide level to disrupt the existing RNA secondary structure (CHIKV-D2S). We show that CHIKV-D2S presents altered DVG generation compared to wild-type virus, correlating with the change in RNA secondary structure obtained by SHAPE-MaP. Our work thus demonstrates that RNA secondary structure impacts CHIKV DVG production during replication.

Low humidity enhances Zika virus infection and dissemination in Aedes aegypti mosquitoes.

As climate change alters Earth's biomes, it is expected the transmission dynamics of mosquito-borne viruses will change. While the effects of temperature changes on mosquito-virus interactions and the spread of the pathogens have been elucidated over the last decade, the impact of relative humidity changes is still relatively unknown. To overcome this knowledge gap, we exposed Aedes aegypti females to various humidity conditions. We measured different components of vectorial capacity such as survival, blood-feeding rates, and changes in infection and dissemination of Zika virus. Survival decreased as the humidity level decreased, while infection rates increased as the humidity level decreased. Alternatively, blood feeding rates and disseminated infection rates peaked at the intermediate 50% relative humidity treatment but were the same in the 30% and 80% relative humidity treatments. These results provide empirical evidence that Ae. aegypti exposure to low humidity can enhance Zika virus infection in the mosquito, which has important implications in predicting how climate change will impact mosquito-borne viruses.IMPORTANCEViruses transmitted by mosquitoes to humans are a major public health burden and are expected to increase under climate change. While we know that temperature is an important driver of variation in arbovirus replication in the mosquito, very little is known about how other relevant climate variables such as humidity will influence the interaction between mosquitoes and the viruses they transmit. Given the variability in humidity across environments, and the predicted changes in humidity under climate change, it is imperative that we also study the impact that it has on mosquito infection and transmission of arboviruses.

Prolonged detection of BPV2 in urine and blood of papillomatosis-affected cattle not grazing bracken fern.

BPV-2 infection can cause bladder infections in cattle that, when associated with bracken fern consumption, can progress to cancerous bladder tumors and also present as bovine enzootic hematuria (BEH). This study aimed to evaluate the prolonged natural BPV-2 infection in the blood and urine of cattle, excluding bracken fern consumption. Thirteen Girolando papillomatosis-affected cattle with no bracken fern contact history were monitored for 20 months. Blood, urine, and wart samples were collected for BPV-2 detection and clinical laboratory analyses. All animals showed the presence of BPV-2 in papillomas and blood, and 92.85% showed BPV-2 in urine, suggesting viral dissemination in the urinary tract. Despite all animals being infected with BPV-2, none showed BEH signs during the study. Thus, it was observed that BPV-2 infection alone didn't induce BEH over 20 months, implying a complex interaction with environmental factors or genetic predisposition. This underlines bracken fern consumption's critical role in urinary bladder carcinogenesis. The study underscores BEH's pathogenesis complexity, advocating longitudinal studies to comprehend BPV-2's role fully.

Transcriptomic analysis unveils bona fide molecular signatures of microglia under conditions of homeostasis and viral encephalitis

Microglia serve as a front-line defense against neuroinvasive viral infection, however, determination of their actual transcriptional profiles under conditions of health and disease is challenging. Here, we used various experimental approaches to delineate the transcriptional landscape of microglia during viral infection. Intriguingly, multiple activation genes were found to be artificially induced in sorted microglia and we demonstrated that shear stress encountered during cell sorting was one of the key inducers. Post-hoc analysis revealed that publicly available large-scale single-cell RNA sequencing datasets were significantly tainted by aberrant signatures that are associated with cell sorting. By exploiting the ribosomal tagging approach, we developed a strategy to enrich microglia-specific transcripts by comparing immunoprecipitated RNA with total RNA. Such enriched transcripts were instrumental in defining bona fide signatures of microglia under conditions of health and virus infection. These unified microglial signatures may serve as a benchmark to retrospectively assess ex vivo artefacts from available atlases. Leveraging the microglial translatome, we found enrichment of genes implicated in T-cell activation and cytokine production during the course of VSV infection. These data linked microglia with T-cell re-stimulation and further underscored that microglia are involved in shaping antiviral T-cell responses in the brain. Collectively, our study defines the transcriptional landscape of microglia under steady state and during viral encephalitis and highlights cellular interactions between microglia and T cells that contribute to the control of virus dissemination.

Understanding the dissemination of viruses and viroids identified through virome analysis of major grapevine rootstocks and RPA-based detection of prevalent grapevine virus B

Grapevine stocks are generally vegetatively propagated for the commercial cultivation. The propagation is predominantly done on rootstocks with >90 % of plant stocks propagated on Dogridge rootstock alone in India. Three additional rootstocks i.e. Paulsen, SO4 and Ramsey are also used for grapevine propagation on a limited scale. However, no information is available on the health status of these rootstocks being used by nurserymen and growers. Therefore, these rootstocks were collected from nurseries of five different locations and subjected to high-throughput sequencing (HTS) to determine the spectrum of viruses and viroids. The de novo assembly of unaligned reads revealed the presence of genome sequences of nine viruses viz. grapevine rupestris stem pitting-associated virus (GRSPaV), grapevine leafroll-associated virus 3 (GLRaV-3), grapevine leafroll-associated virus 4 (GLRaV-4), grapevine virus A (GVA), grapevine virus B (GVB), grapevine virus D (GVD), grapevine virus F (GVF), grapevine virus L (GVL), grapevine fleck virus (GFkV) and five viroids viz. hopstunt viroid (HSVd), grapevine yellow speckle viroid 1 and 2 (GYSVd-1 and GYSVd-2), Australian grapevine viroid (AGVd) and grapevine latent viroid (GLVd). The identified viruses and viroids were further confirmed through RT-PCR and Sanger sequencing. Indexing for the presence of these graft-transmissible pathogens in 43 rootstocks and 23 scion samples collected through field surveys indicated that infected rootstocks are the probable source for dissemination of these viruses and viroids in grapevine scions. As GVB was the most prevalent virus in all the rootstocks and scions as observed in RT-PCR testing, a simplified crude sap-based recombinase polymerase amplification (RPA) assay was optimized for its rapid detection. The present study highlights that grapevine rootstocks are reservoir of viruses and viroids and source for their dissemination in grapevine vineyards. Findings of the study including the optimized simplified cost-effective isothermal nucleic acid-based detection technique for GVB will be highly useful for production of certified clean rootstocks of grapevine in India.

Spatial kinetics and immune control of murine cytomegalovirus infection in the salivary glands.

Human cytomegalovirus (HCMV) is the most common congenital infection. Several HCMV vaccines are in development, but none have yet been approved. An understanding of the kinetics of CMV replication and transmission may inform the rational design of vaccines to prevent this infection. The salivary glands (SG) are an important site of sustained CMV replication following primary infection and during viral reactivation from latency. As such, the strength of the immune response in the SG likely influences viral dissemination within and between hosts. To study the relationship between the immune response and viral replication in the SG, and viral dissemination from the SG to other tissues, mice were infected with low doses of murine CMV (MCMV). Following intra-SG inoculation, we characterized the viral and immunological dynamics in the SG, blood, and spleen, and identified organ-specific immune correlates of protection. Using these data, we constructed compartmental mathematical models of MCMV infection. Model fitting to data and analysis indicate the importance of cellular immune responses in different organs and point to a threshold of infection within the SG necessary for the establishment and spread of infection.

Insights into the Complexity and Functionality of Plant Virus Protein Phosphorylation.

Phosphorylation, the most extensive and pleiotropic form of protein posttranslation modification, is central to cellular signal transduction. Throughout the extensive co-evolution of plant hosts and viruses, modifications to phosphorylation have served multiple purposes. Such modifications highlight the evolutionary trajectories of viruses and their hosts, with pivotal roles in regulation and refinement of host-virus interactions. In plant hosts, protein phosphorylation orchestrates immune responses, enhancing the activities of defense-related proteins such as kinases and transcription factors, thereby strengthening pathogen resistance in plants. Moreover, phosphorylation influences the interactions between host and viral proteins, altering viral spread and replication within host plants. In the context of plant viruses, protein phosphorylation controls key aspects of the infection cycle, including viral protein functionality and the interplay between viruses and host plant cells, leading to effects on viral accumulation and dissemination within plant tissues. Explorations of the nuances of protein phosphorylation in plant hosts and their interactions with viruses are particularly important. This review provides a systematic summary of the biological roles of the proteins of plant viruses carrying diverse genomes in regulating infection and host responses through changes in the phosphorylation status. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Viral shedding and environmental dispersion of two clade 2.3.4.4b H5 high pathogenicity avian influenza viruses in experimentally infected mule ducks: implications for environmental sampling

High pathogenicity avian influenza viruses (HPAIVs) have caused major epizootics in recent years, with devastating consequences for poultry and wildlife worldwide. Domestic and wild ducks can be highly susceptible to HPAIVs, and infection leads to efficient viral replication and massive shedding (i.e., high titres for an extended time), contributing to widespread viral dissemination. Importantly, ducks are known to shed high amounts of virus in the earliest phase of infection, but the dynamics and impact of environmental contamination on the epidemiology of HPAIV outbreaks are poorly understood. In this study, we monitored mule ducks experimentally infected with two H5N8 clade 2.3.4.4b goose/Guangdong HPAIVs sampled in France in 2016–2017 and 2020–2021 epizootics. We investigated viral shedding dynamics in the oropharynx, cloaca, conjunctiva, and feathers; bird-to-bird viral transmission; and the role of the environment in viral spread and as a source of samples for early detection and surveillance. Our findings showed that viral shedding started before the onset of clinical signs, i.e., as early as 1 day post-inoculation (dpi) or post-contact exposure, peaked at 4 dpi, and lasted for up to 14 dpi. The detection of viral RNA in aerosols, dust, and water samples mirrored viral shedding dynamics, and viral isolation from these environmental samples was successful throughout the experiment. Our results confirm that mule ducks can shed high HPAIV titres through the four excretion routes tested (oropharyngeal, cloacal, conjunctival, and feather) while being asymptomatic and that environmental sampling could be a non-invasive tool for early viral RNA detection in HPAIV-infected farms.

Eosinophils protect against SARS-CoV-2 following a vaccine breakthrough infection.

Waning immunity and the emergence of immune evasive SARS-CoV-2 variants jeopardize vaccine efficacy leading to breakthrough infections. We have previously shown that innate immune cells play a critical role in controlling SARS-CoV-2. To investigate the innate immune response during breakthrough infections, we modeled breakthrough infections by challenging low-dose vaccinated mice with a vaccine-mismatched SARS-CoV-2 Beta variant. We found that low-dose vaccinated infected mice had a 2-log reduction in lung viral burden, but increased immune cell infiltration in the lung parenchyma, characterized by monocytes, monocyte-derived macrophages, and eosinophils. Single cell RNA-seq revealed viral RNA was highly associated with eosinophils that corresponded to a unique IFN-γ biased signature. Antibody-mediated depletion of eosinophils in vaccinated mice resulted in increased virus replication and dissemination in the lungs, demonstrating that eosinophils in the lungs are protective during SARS-CoV-2 breakthrough infections. These results highlight the critical role for the innate immune response in vaccine mediated protection against SARS-CoV-2.

The human CD47 checkpoint is targeted by an immunosuppressive Aedes aegypti salivary factor to enhance arboviral skin infectivity.

The Aedes aegypti mosquito is a vector of many infectious agents, including flaviviruses such as Zika virus. Components of mosquito saliva have pleomorphic effects on the vertebrate host to enhance blood feeding, and these changes also create a favorable niche for pathogen replication and dissemination. Here, we demonstrate that human CD47, which is known to be involved in various immune processes, interacts with a 34-kilodalton mosquito salivary protein named Nest1. Nest1 is up-regulated in blood-fed female A. aegypti and facilitates Zika virus dissemination in human skin explants. Nest1 has a stronger affinity for CD47 than its natural ligand, signal regulatory protein α, competing for binding at the same interface. The interaction between Nest1 with CD47 suppresses phagocytosis by human macrophages and inhibits proinflammatory responses by white blood cells, thereby suppressing antiviral responses in the skin. This interaction elucidates how an arthropod protein alters the human response to promote arbovirus infectivity.

Aedes aegypti Mosquito Probing Enhances Dengue Virus Infection of Resident Myeloid Cells in Human Skin.

The most prevalent arthropod-borne viruses, including the dengue viruses, are primarily transmitted by infected mosquitoes. However, the dynamics of dengue virus (DENV) infection and dissemination in human skin following Aedes aegypti probing remain poorly understood. We exposed human skin explants to adult female Ae. aegypti mosquitoes following their infection with DENV-2 by intrathoracic injection. Skin explants inoculated with a similar quantity of DENV-2 by a bifurcated needle were used as controls. Quantitative in situ imaging revealed that DENV replication was greatest in keratinocytes in the base of the epidermis, accounting for 50-60% of all infected cells regardless of the route of inoculation. However, DENV inoculation by Ae. aegypti probing resulted in an earlier and increased viral replication in the dermis, infecting twice as many cells at 24 h when compared to needle inoculation. Within the dermis, enhanced replication of DENV by Ae. aegypti infected mosquitoes was mediated by increased local recruitment of skin-resident macrophages, dermal dendritic cells, and epidermal Langerhans cells relative to needle inoculation. An enhanced but less pronounced influx of resident myeloid cells to the site of mosquito probing was also observed in the absence of infection. Ae. aegypti probing also increased recruitment and infection of dermal mast cells. Our findings reveal for the first time that keratinocytes are the primary targets of DENV infection following Ae. aegypti inoculation, even though most of the virus is inoculated into the dermis during probing. The data also show that mosquito probing promotes the local recruitment and infection of skin-resident myeloid cells in the absence of an intact vasculature, indicating that influx of blood-derived neutrophils is not an essential requirement for DENV spread within and out of skin.

Immediate myeloid depot for SARS-CoV-2 in the human lung.

In the pathogenesis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, epithelial populations in the distal lung expressing Angiotensin-converting enzyme 2 (ACE2) are infrequent, and therefore, the model of viral expansion and immune cell engagement remains incompletely understood. Using human lungs to investigate early host-viral pathogenesis, we found that SARS-CoV-2 had a rapid and specific tropism for myeloid populations. Human alveolar macrophages (AMs) reliably expressed ACE2 allowing both spike-ACE2-dependent viral entry and infection. In contrast to Influenza A virus, SARS-CoV-2 infection of AMs was productive, amplifying viral titers. While AMs generated new viruses, the interferon responses to SARS-CoV-2 were muted, hiding the viral dissemination from specific antiviral immune responses. The reliable and veiled viral depot in myeloid cells in the very early phases of SARS-CoV-2 infection of human lungs enables viral expansion in the distal lung and potentially licenses subsequent immune pathologies.

Cytoskeleton-associated gelsolin responds to the midgut distention process in saline meal-fed Aedes aegypti and affects arbovirus dissemination from the midgut.

The mosquito, Aedes aegypti, is the principal vector for several arboviruses. The mosquito midgut is the initial tissue that gets infected with an arbovirus acquired along with a blood meal from a vertebrate host. Blood meal ingestion leads to midgut tissue distention thereby increasing the pore size of the surrounding basal lamina. This allows newly synthesized virions to exit the midgut by traversing the distended basal lamina to infect secondary tissues of the mosquito. We conducted a quantitative label-free proteomic time course analysis with saline meal-fed Ae. aegypti females to identify host factors involved in midgut tissue distention. Around 2000 proteins were detected during each of the seven sampling time points and 164 of those were uniquely expressed. Forty-five of 97 differentially expressed proteins were upregulated during the 96-h time course and most of those were involved in cytoskeleton modulation, metabolic activity, and vesicle/vacuole formation. The F-actin-modulating Ae. aegypti (Aa)-gelsolin was selected for further functional studies. Stable knockout of Aa-gelsolin resulted in a mosquito line, which showed distorted actin filaments in midgut-associated tissues likely due to diminished F-actin processing by gelsolin. Zika virus dissemination from the midgut of these mosquitoes was diminished and delayed. The loss of Aa-gelsolin function was associated with an increased induction of apoptosis in midgut tissue indicating an involvement of Aa-gelsolin in apoptotic signaling in mosquitoes. Here, we used proteomics to discover a novel host factor, Aa-gelsolin, which affects the midgut escape barrier for arboviruses in mosquitoes and apoptotic signaling in the midgut.

Impact of nebulization versus metered-dose inhaler utilization on viral particle dispersion in patients with COVID-19.

Conflicting guidance exists regarding the characterization of nebulization as an aerosol-generating procedure and subsequent risk of transmission of SARS-CoV-2 to healthcare workers. This study sought to address whether SARS-CoV-2 viral load distribution was impacted by bronchodilator delivery via nebulizer versus metered-dose inhaler (MDI). Adults infected with COVID-19 were enrolled and received a single dose of albuterol sulfate nebulized solution (2.5mg/3mL via breath-actuated nebulizer with filtered mouthpiece) or albuterol sulfate hydrofluoroalkane inhalation aerosol (90µg/actuation; two puffs via MDI with spacer) in a randomized crossover sequence. Air and surfaces were sampled at predefined locations within patients' hospital rooms to assess SARS-CoV-2 dispersion over three periods (baseline, MDI, and nebulizer). Eleven patients received crossover therapy. Six patients had detectable SARS-CoV-2 RNA during one treatment period (n = 3 each for MDI and nebulizer) and one during both treatment periods. No viral RNA was found in the rooms of four (36.4%) patients. Overall, few environmental samples (17/397; 4.3%) contained detectable viral RNA, with no meaningful differences in positivity rate across periods; RNA genome copy numbers were low in positive samples. No correlation between dispersion and patient clinical status or environmental parameters was observed. In this first prospective trial evaluating viral load distribution following use of nebulizer versus MDI in hospitalized patients with COVID-19, low environmental contamination was found regardless of administration method. Findings support the use of either device when needed to treat patients with COVID-19.

Urban Air Pollution Exposure Impact on COVID-19 Transmission in a Few Metropolitan Regions

Based on outdoor air pollution and meteorological daily time series observational and in-situ monitoring data, this study investigated the impacts of environmental factors under different urban climates on COVID-19 transmission in four hotspot European metropolises (Berlin, London, Madrid, and Paris) from March 2020 to March 2022. Through applied statistical methods and cross-correlation tests involving multiple datasets pertaining to the main air pollutants (inhalable particulate matter PM2.5 and PM10, nitrogen dioxide (NO2), and ozone (O3)) and climate parameters (air temperature at 2 m height, relative humidity, wind speed intensity and direction, planetary boundary layer height, and surface solar irradiance), a direct positive impact of aerosol loading (PM2.5, PM10, and aerosol optical depth (AOD)) on COVID-19 spreading and severity was revealed. Despite some urban differences existing between the selected cities, particularly for the spring–summer periods, we have observed negative correlations between daily new COVID-19 cases and deaths and daily average ground-level ozone concentration, air temperature at 2 m height, planetary boundary layer height, and surface solar irradiance. Air relative humidity and urban population density have a direct impact on COVID-19 diffusion in large metropolitan areas, and the findings of this study highlight the crucial role of air pollution, in synergy with climate variability, in viral pathogens dispersion in COVID-19 transmission in large urban areas. This information can be used by decision-makers to develop targeted interventions during epidemic periods to reduce the potential risks associated with air pollution exposure and to promote the sustainable development of urban economies.

Analysis of problems and countermeasures in computer network engineering security

This paper analyzes the existing security issues in computer network engineering and proposes a series of countermeasures. To address the problems of hacker attacks and information leakage, it is recommended to strengthen network monitoring and the application of encryption technology. For the issues of malware and virus dissemination, it is advised to regularly update antivirus software and enhance employee security awareness training. Regarding network data leakage and privacy breaches, the use of secure transmission protocols and multi-factor authentication technology is advocated. For network security management and maintenance issues, establishing a sound security management system and emergency response plans is recommended to ensure the stable operation of network systems. Through the implementation of the above measures, the security level of computer network engineering can be effectively improved, ensuring the normal operation of network systems and the security of information.

Comparison of strain specific pathogenicity of Herpes Simplex Virus Type 1 by high-throughput sequencing

Herpes Simplex Virus Type 1 (HSV-1) is a widespread human pathogen known for causing a spectrum of clinical manifestations, ranging from mild cold sores to severe complications like encephalitis. Understanding the strain-specific variations of HSV-1 is crucial for elucidating its pathogenesis and developing targeted therapeutic interventions. In this multifaceted study, we investigated the strain-specific characteristics of HSV-1 using an in vivo rat model. Firstly, a pilot study was conducted to assess the capacity of three HSV-1 strains (Fisher (F), KOS (K), and MacIntyre (M)) to induce cold sores in rats. Remarkably, the F strain exhibited pronounced pathogenicity, inducing erythema, swelling, and disrupted epidermis with ulceration, distinguishing it from the K and M strains. Subsequently, the treatment capability of intravenous acyclovir injection in HSV-1 F strain-infected rats was evaluated. Acyclovir treatment resulted in a significant reduction in HSV-1 viral copy numbers in serum and dissected neuronal tissues, particularly in the spinal cord, brain, and lower lip. Lastly, whole genome sequencing data revealed that high-impact mutations occurred in the K and M strains within the UL49, US2, and US3 genes. These mutations may play a pivotal role in influencing viral replication, dissemination, pathogenesis, and infectivity. In contrast, the moderate missense variant mutations detected in the US12, US8, UL3, UL30, UL31, and UL36 genes appeared to have no effect on viral pathogenesis and infectivity, based on RT-PCR data for spinal cord, trigeminal nerve, brain, and the lower lip. These strain-specific mutations underscore the dynamic nature of HSV-1 evolution. Collectively, our findings contribute to a deeper understanding of HSV-1 strain diversity and pave the way for the development of targeted therapeutic strategies against this medically significant virus.