Prevalent Virus Research Articles

Insulin-mediated endothelin signaling is antiviral during West Nile virus infection.

Arboviruses, particularly those transmitted by mosquitoes, pose a significant threat to humans and are an increasing concern because of climate change, human activity, and expanding vector-competent populations. West Nile virus is of significant concern as the most frequent mosquito-borne disease transmitted annually within the continental United States. Here, we identify a previously uncharacterized signaling pathway that impacts West Nile virus infection, namely endothelin signaling. Additionally, we demonstrate that we can successfully translate results obtained from D. melanogaster into the more relevant human system. Our results add to the growing field of insulin-mediated antiviral immunity and identify potential biomarkers or intervention targets to better address West Nile virus infection and severe disease.

A-299 Clinical Performance Validation of 7 qPCR Kits for the Specific Diagnosis of 5 Enteric Viruses in Clinical Stool Samples

Abstract Background Among the most prevalent enteric viruses associated with gastroenteritis are norovirus (NoV), rotavirus (RV), astrovirus (AstV), sapovirus (SaV) and adenovirus (AdV). The diagnosis of infections associated with gastroenteritis viruses is mainly based on the detection of the genome of these viruses by molecular methods, mainly qPCR and RTqPCR reactions. The aim of this study was to validate the diagnostic performance of 7 qPCR diagnostic kits of the “VIASURE Real Time PCR Detection Kits” series with respect to commercial reference kits used for the diagnosis of these pathogens. Methods A total of 318 clinical stool samples were used, including: 213 stool samples from children from sporadic cases of gastroenteritis collected between 2016–2018; 94 samples from outbreaks of gastroenteritis caused by NoV between 2017–2019; and 11 samples from healthy children with asymptomatic enteric virus infections collected between 2017–2018. Seven VIASURE kits were used for the specific detection of enteric viruses. At the same time, samples were also tested with the following commercial kits used as reference methods: RIDA®GENE Viral Stool Panel II (rotavirus, adenovirus 40/41 and astrovirus) and RIDA®GENE Sapovirus, RIDA®GENE Norovirus I & II. In the case of AdV, the positivity of the samples was confirmed using the qPCR protocol published by Heim et al. (2003). Results The results obtained are summarized in Table 1. Conclusion The results obtained show a high sensitivity and specificity of the VIASURE kits for the detection of rotavirus, adenovirus, sapovirus, astrovirus and norovirus GI and GII (in the latter case using both the monoplex and multiplex product). In addition, it should be noted that all these kits share the same thermal protocol, thus allowing their joint use for the simultaneous diagnosis of these 5 enteric viruses.

Respiratory virus infections in decedents in a large, urban medical examiner's office

ObjectiveMost respiratory virus surveillance relies on medically attended respiratory illness, but an understanding of the true patterns of infection independent of care-seeking behaviour would enhance clinical and public health responses to respiratory virus outbreaks. We evaluated the potential of decedent surveillance by estimating the burden of respiratory virus infection in decedents in a large, urban medical examiner's office. Study designObservational. MethodsIn 2020–2022, we tested nasopharyngeal swabs from 4121 decedents in Detroit, Michigan for 15 respiratory viruses, including SARS-CoV-2, respiratory syncytial virus, and influenza virus A and B. We analysed infection prevalence over time and by age, sex, race/ethnicity, and manner of death. ResultsOf 4113 valid tests, 30.2% were positive for at least one virus, and 6.1% were positive for multiple viruses. All viruses were detected except for influenza A/H1N1 and influenza B. The most prevalent viruses were SARS-CoV-2 (15.7%), rhinovirus (11.2%), and adenovirus (4.9%), which were detected in all months. Most viruses exhibited decreasing prevalence with age, higher prevalence among Black and Hispanic than among White decedents and lower prevalence among deaths from natural causes; SARS-CoV-2 was a notable exception to the patterns by age and manner of death, instead reflecting community trends in catchment counties. ConclusionsThere was high prevalence and diversity of respiratory viruses in decedents entering a large, urban medical examiner's office. Decedent surveillance could offer a clearer picture of the true underlying burden of infection, motivating public health priorities for intervention and vaccine development, and augmenting data for real-time response to respiratory virus outbreaks.

Genetic diversity and characterization of rhinoviruses from Chinese clinical samples with a global perspective.

Rhinovirus (RV) is a significant pathogen causing upper and lower respiratory diseases and is one of the most prevalent human respiratory viruses. However, research on the genetic diversity and evolutionary dynamics of RVs in China and worldwide remains limited. To address this knowledge gap, we utilized Chinese clinical RV samples as a starting point and detected and reported 22 types, including A9, B3, and C13, in China for the first time. Among these, A67, A76, and A106 were also detected and reported in Asia for the first time, characterizing their genetic diversity. We also identified A110 as a novel type of RVA and reported its distinctive characteristics in phylogeny, secondary structure, and capsid protein structure. Furthermore, by mining, refining, and annotating RV sequence data available worldwide, four previously unreported novel types, B107, C58, C59, and C60, were identified, and their genetic diversity was revealed. Furthermore, we observed variations in the guanine-cytosine (GC) content among different serotypes and clades. Also of note was that, based on a complete and refined VP1 data set, the evolutionary dynamics of RV were analyzed systematically and on a large scale for the first time. IMPORTANCE Based on clinical samples collected in China, we detected and reported 22 types for the first time in China, as well as three types for the first time in Asia, and reported their genetic characteristics and diversity. We identified a novel type of Rhinovirus (RV), A110, highlighting its unique genetic features. We annotated the genomic structure and serotype of all the existing RV sequences in the database, and four novel RV types were identified and their genetic diversity reported. Combined with the sequence annotation, we constructed a complete VP1 data set of RV and conducted the first large-scale evolutionary dynamics analysis of RV. Based on a high-quality data set, we conducted a comprehensive analysis of the guanine-cytosine (GC) content variations among serotypes of RVs. This study provides crucial theoretical support and valuable data for understanding RV's genetic diversity and developing antiviral strategies.

Surveillance of respiratory viruses at health facilities from across Kenya, 2014

Background: Acute respiratory illnesses (ARI) are a major cause of morbidity and mortality globally. With (re)emergence of novel viruses and increased access to childhood bacterial vaccines, viruses have assumed greater importance in the aetiology of ARI. There are now promising candidate vaccines against some of the most common endemic respiratory viruses. Optimal delivery strategies for these vaccines, and the need for interventions against other respiratory viruses, requires geographically diverse data capturing temporal variations in virus circulation. Methods: We leveraged three health facility-based respiratory illness surveillance platforms operating in 11 sites across Kenya. Nasopharyngeal (NP) and/or oropharyngeal (OP) specimens, patient demographic, and clinical characteristics were collected in 2014 from individuals of various ages presenting with respiratory symptoms at the surveillance facilities. Real time multiplex polymerase chain reaction was used to detect rhinoviruses, respiratory syncytial virus (RSV), influenza virus, human coronaviruses (hCoV), and adenoviruses. Results: From 11 sites, 5451 NP/OP specimens were collected and tested from patients. Of these, 40.2% were positive for at least one of the targeted respiratory viruses. The most frequently detected were rhinoviruses (17.0%) and RSV A/B (10.5%), followed by influenza A (6.2%), adenovirus (6.0%) and hCoV (4.2%). RSV was most prevalent among infants aged <12 months old (18.9%), adenovirus among children aged 12–23 months old (11.0%), influenza A among children aged 24–59 months (9.3%), and rhinovirus across all age groups (range, 12.7–19.0%). The overall percent virus positivity varied by surveillance site, health facility type and case definition used in surveillance. Conclusions: We identify rhinoviruses, RSV, and influenza A as the most prevalent respiratory viruses. Higher RSV positivity in inpatient settings compared to outpatient clinics strengthen the case for RSV vaccination. To inform the design and delivery of public health interventions, long-term surveillance is required to establish regional heterogeneities in respiratory virus circulation and seasonality.

Differential seasonal prevalence of yellowing viruses infecting melon crops in southern California and Arizona determined by multiplex RT-PCR and RT-qPCR.

Viruses transmitted by the whitefly (Bemisia tabaci) are an increasing threat to cucurbit production in the southwestern United States as well as many other cucurbit production regions throughout the world. The crinivirus, cucurbit yellow stunting disorder virus (CYSDV), has severely impacted melon production in California and Arizona since its introduction to the region in 2006. Within the past few years, another crinivirus, cucurbit chlorotic yellows virus (CCYV), and the whitefly-transmitted ipomovirus, squash vein yellowing virus (SqVYV) were found infecting melon plants in California's Imperial Valley as well. Both CYSDV and CCYV, as well as an aphid transmitted polerovirus, cucurbit aphid-borne yellows virus (CABYV), occur together in the region and produce identical yellowing symptoms on cucurbit plants. Mixed infections of these four viruses both in the Sonoran Desert and other regions pose challenges for disease management and efforts to develop resistant varieties. A multiplex single-step RT-PCR method was developed that differentiates these viruses from one another, and this was used to determine the prevalence and distribution these viruses in melon samples collected from fields in the Sonoran Desert melon production region of California and Arizona, USA during spring and fall melon seasons from 2019 through 2021. TaqMan probes were also developed, optimized, and applied in a single-step multiplex RT-qPCR to quantify titers of these four viruses in plant samples, which frequently carry mixed infections. Results of the multiplex RT-PCR analysis demonstrated that CYSDV is the predominant virus during the fall season, whereas CCYV was by far the most prevalent virus during spring seasons each year. Multiplex RT-qPCR was used to evaluate differential accumulation and spatio-temporal distribution of viruses within plants and suggested differences in competitive accumulation of CCYV and CYSDV within melon. This study also provides the first official report of SqVYV in Arizona, USA, and offers an efficient method for virus detection and quantification for breeding and disease management in areas impacted by cucurbit yellowing viruses.

Comparative Analysis of Pediatric Hospitalizations during Two Consecutive Influenza and Respiratory Virus Seasons Post-Pandemic.

The COVID-19 pandemic has had a significant impact on the epidemiology of respiratory viruses. Non-pharmaceutical interventions (NPIs) led to a dramatic reduction in respiratory infections. However, the long-term effects on respiratory virus epidemiology remain unclear. We conducted a comparative study on hospitalized pediatric patients with respiratory illness during two seasons: 1 October 2021 to 15 March 2022 and 1 October 2022 to 15 March 2023. We compared the type of virus, mean duration of hospitalization, and disease severity. In the first season, 47.1% of patients (65/138) tested positive for at least one respiratory virus, with respiratory syncytial virus (RSV) being the most frequent (23.2%). In the second season, 82.9% of patients (102/123) tested positive, with RSV and Rhinovirus being the most prevalent (28.38% and 27.03%, respectively). Other viruses, such as Influenza A/B, Metapneumovirus, and Adenovirus, also showed increased prevalence. Disease severity and mean duration of hospitalization were similar between the two seasons. Our study highlights increased prevalence in respiratory viruses, including RSV and Rhinovirus, following the easing of NPIs. The prevalence in respiratory viruses, including RSV and Rhinovirus, increased in the second season compared to the first one. Interestingly, RSV's peak incidence shifted from February to November. The emergence of rhinovirus as the most prevalent respiratory virus during certain months suggests viral competition and dynamic changes in viral circulation. The overall severity of respiratory infections remained relatively stable between the seasons.

The relationship between vector insect populations, natural enemies, and disease incidence of tungro virus during wet and dry seasons

Abstract. Hutasoit RT, Jihad M, Listihani L, Selangga DGW. 2023. The relationship between vector insect populations, natural enemies, and disease incidence of tungro virus during wet and dry seasons. Biodiversitas 24: 4001-4007. Tungro virus is one of the most prevalent viruses affecting rice plants. The tungro virus is frequently found in rice plantations because its green planthopper vector is always present. This study aimed to determine the relationship between the population density of green planthoppers and its natural enemies with the incidence of tungro disease during the rainy and dry seasons in Lanrang, Sidenreng Rappang, South Sulawesi. The research method employed was field monitoring of the population density of green planthoppers, natural enemies, and the incidence of tungro disease. The presence of the tungro virus was confirmed by the molecular method using RTSV and RTBV-specific primers. The results showed three types of tungro vector insects: Nephotettix virescens, Nephotettix nigropictus, and Recilia dorsalis. Nephotettix virescens was the dominant vector insect, with the highest population in March and August of 101 and 51 individuals, respectively. During the dry season, the high population of the three vector insects in August was followed by a high incidence of tungro disease in September, reaching 29.38%. Symptoms of yellow leaves have been confirmed by molecular methods, which indicated that the infection was caused by RTSV and RTBV, as evidenced by the amplification of DNA bands measuring 787 bp and 1400 bp. Data on the population of vector insects and the incidence of tungro disease indicated the importance of determining the ideal time to plant to avoid the plant's susceptible phase during the peak vector population between March and August. The dominant natural enemies found during the observations included Araneus inustus, Tetragnatha maxillosa, Agriocnemis pygmaea, and Menochilus sexmaculatus. Increasing the population of natural enemies could suppress the population of vector insects.

The Association of Cytomegalovirus and Allostatic Load by Country of Birth and Length of Time in the United States.

Cytomegalovirus (CMV) is a highly prevalent virus with a worldwide distribution. It typically remains dormant in most individuals until reactivation. Immunocompromised states are known to be potential causes for CMV reactivation. Current research has shown a link in the decline of immigrant health among those living in the US for an extended period, though the impact of CMV on this is not clear. This study investigated the association between country of birth, duration of US residency, allostatic load, and latent cytomegalovirus infection (CMV IgG) in a sample of US adults aged 20-49. The data utilized for our analysis was obtained from the National Health and Nutrition Examination Survey (NHANES) conducted between 2001 and 2004. Allostatic load, an index measuring the cumulative physiological strain on the body as it strives to regain stability in the presence of chronic stress, provided a valuable approach to assess stress within the context of CMV exposure. Logistic regression modeling was employed to estimate odds ratios and confidence intervals for the analysis. The chi-square test of association and Cramer's V statistic were used to assess the correlation among categorical variables, while Pearson's correlation coefficient was applied to evaluate the relationship between continuous variables. The results revealed that individuals born outside the US and those with less than 20 years of residency in the US exhibited significantly higher proportions of positive CMV IgG compared to individuals born in the US. Specifically, individuals born outside the US had more than triple the odds of CMV IgG when adjusting for the AL index (OR = 3.69, p-value = 0.0063). A similar trend was observed when examining AL risk based on the duration of US residency. Furthermore, age and sex were identified as significant predictors (p-value < 0.05) of AL risk, considering the individual's country of birth. In summary, the findings of this study significantly enhance our comprehension of the intricate interplay between cytomegalovirus (CMV) and allostatic load (AL). The investigation sheds light on how CMV and AL interact within specific demographic contexts, providing valuable insights into the underlying risk factors for CMV infection.

Epidemiological characterization of viral etiological agents of the central nervous system infections among hospitalized patients in Egypt between 2016 and 2019

Viral infections of the central nervous system (CNS) are common worldwide and result in considerable morbidity and mortality associated with neurologic illness. Until now, there have been no epidemiologic data regarding viruses causing aseptic meningitis, encephalitis, and CNS infections in Egypt. We investigated 1735 archived cerebrospinal fluid samples collected from Egyptian patients between 2016 and 2019 and performed molecular characterization for infection for12 different viruses: herpes simplex viruses 1 and 2 (HSV-1 and HSV-2), varicella-zoster virus (VZV), Epstein–Barr virus (EBV), cytomegalovirus (CMV), human herpesviruses 6 and 7 (HHV-6 and HHV-7), human enteroviruses (HEVs), human parechovirus (HPeV), parvovirus B19 (B19V), adenovirus (AdV), and mumps virus (MuV). All included samples were negative for bacterial infection. Our results indicated a relatively high prevalence of viral infection, with HEVs being the most prevalent viruses, followed by HSV-1, EBV, and then HSV-2. The highest prevalence was among male patients, peaking during the summer. Data obtained from this study will contribute to improving the clinical management of viral infections of the CNS in Egypt.

The Utility of Metagenomic Next-Generation Sequencing (mNGS) in the Management of Patients With Bronchiectasis: A Single-Center Retrospective Study of 93 Cases.

Bronchiectasis is a chronic inflammatory respiratory disease mainly caused by pathogenic infections. However, standard methods of pathogen detection show prolonged cycle durations and unsatisfactory sensitivity and detection rates. Macrogenomic next-generation sequencing (mNGS) emerges as a promising technique for swift, effective, and unbiased pathogen detection and subsequent data interpretation. Here, a retrospective analysis of 93 patients with suspected bronchiectasis was performed to assess the clinical applicability of mNGS. Bronchoalveolar alveolar lavage fluid (BALF) samples were collected from these subjects, followed by standard assays and mNGS separately. The turnaround time, detection rate, and pathogen identification using mNGS were compared with those of standard methods. mNGS identified a greater number of bacteria (72 vs 16), fungi (26 vs 19), and viruses (14 vs 0) than standard methods. Specifically, the commonly identified bacteria were Haemophilus, Mycobacterium intracellulare, Pseudomonas, and Streptococcus pneumoniae, while the most detected fungi were Aspergillus and the most prevalent viruses were human herpesviruses. Of note, 29 out of 30 patients (96.67%) who received optimized treatment strategies based on mNGS results experienced recovery. Collectively, these findings suggest that mNGS has the potential to improve the diagnosis and treatment of bronchiectasis patients by enabling rapid and precise pathogen detection, which can lead to timely and effective treatment strategies.

Feline herpesvirus 1 (FHV-1) enters the cell by receptor-mediated endocytosis.

Feline herpesvirus type 1 (FHV-1) is an enveloped dsDNA virus belonging to the Herpesviridae family and is considered one of the two primary viral etiological factors of feline upper respiratory tract disease. In this study, we investigated the entry of FHV-1 into host cells using two models: the AK-D cell line and primary feline skin fibroblasts (FSFs). We employed confocal microscopy, siRNA silencing, and selective inhibitors of various entry pathways. Our observations revealed that the virus enters cells via pH and dynamin-dependent endocytosis, as the infection was significantly inhibited by NH4Cl, bafilomycin A1, dynasore, and mitmab. Additionally, genistein, nystatin, and filipin treatments, siRNA knock-down of caveolin-1, as well as FHV-1 and caveolin-1 colocalization suggest the involvement of caveolin-mediated endocytosis during the entry process. siRNA knock-down of clathrin heavy chain and analysis of virus particle colocalization with clathrin indicated that clathrin-mediated endocytosis also takes part in the primary cells. This is the first study to systematically examine FHV-1 entry into host cells, and for the first time, we describe FHV-1 replication in AK-D and FSFs. IMPORTANCE Feline herpesvirus 1 (FHV-1) is one of the most prevalent viruses in cats, causing feline viral rhinotracheitis, which is responsible for over half of viral upper respiratory diseases in cats and can lead to ocular lesions resulting in loss of sight. Although the available vaccine reduces the severity of the disease, it does not prevent infection or limit virus shedding. Despite the clinical relevance, the entry mechanisms of FHV-1 have not been thoroughly studied. Considering the limitations of commonly used models based on immortalized cells, we sought to verify our findings using primary feline skin fibroblasts, the natural target for infection in cats.

Maintenance of a host-specific minority mutation in the West Nile virus NS3

West Nile virus (WNV), the most prevalent arthropod-borne virus (arbovirus) in the United States, is maintained in a cycle between Culex spp. mosquitoes and birds. Arboviruses exist within hosts and vectors as a diverse set of closely related genotypes. In theory, this genetic diversity can facilitate adaptation to distinct environments during host cycling, yet host-specific fitness of minority genotypes has not been assessed. Utilizing WNV deep-sequencing data, we previously identified a naturally occurring, mosquito-biased substitution, NS3 P319L. Using both cell culture and experimental infection in natural hosts, we demonstrated that this substitution confers attenuation in vertebrate hosts and increased transmissibility by mosquitoes. Biochemical assays demonstrated temperature-sensitive ATPase activity consistent with host-specific phenotypes. Together these data confirm the maintenance of host-specific minority variants in arbovirus mutant swarms, suggest a unique role for NS3 in viral fitness, and demonstrate that intrahost sequence data can inform mechanisms of host-specific adaptation.

Occurrence and distribution of Grapevine pinot gris virus and other grapevine viruses in German viticultural regions

To determine the occurrence and distribution of prevalent viruses in commercially important vineyards, a survey was carried out in all thirteen wine-growing regions in Germany. Results reveal that the recently emerged Grapevine pinot gris virus (GPGV) was the most abundant virus with a percentage of 18% prevalence, followed by 13% Grapevine fleck virus (GFkV), 9% Grapevine leafroll-associated virus 1 (GLRaV-1), 4% Grapevine fanleaf virus (GFLV), 2% Raspberry ringspot virus (RpRSV), 2% Arabis mosaic virus (ArMV) and 2% Grapevine leafroll-associated virus 3 (GLRaV-3). Distribution of some viruses varies greatly between individual regions, thus regional hotspots or gradients were detected. GPGV for example is mostly found in southeastern Germany, while its incidence decreases to the north along the river Rhine. The findings of this survey provide an overview of the allocation of the most prevalent grapevine viruses in Germany and can support regional virus management and national risk assessment especially GPGV.

Effect of duck interferon-α and an anti-cap protein polyclonal antibody against duck circovirus

Duck circovirus (DuCV) is one of the most prevalent viruses in the duck breeding industry, and causes persistent infection and severe immunosuppression. Currently, there is a serious lack of prevention and control measures and no commercial vaccine against DuCV. Therefore, effective antiviral drugs are important for treating DuCV infection. Interferon (IFN) is an important component of antiviral innate immunity, but it remains unclear whether duck IFN-α has a clinical effect against DuCV. Antibody therapy is an important way to treat viral infections. The DuCV structural protein (cap) is immunogenic, and it remains to be determined whether an anti-cap protein antibody can effectively block DuCV infection. In this study, the duck IFN-α gene and the DuCV structural protein cap gene were cloned, expressed and purified in Escherichia coli to prepare duck recombinant IFN-α and the cap protein. Then, rabbits were immunized with the recombinant cap protein to prepare a rabbit polyclonal antibody. This study investigated the antiviral effect of duck recombinant IFN-α and the anti-cap protein antibody and their combined effect on Cherry Valley ducks infected with DuCV. The results showed that the treatment significantly alleviated the clinical symptoms of immune organ atrophy and immunosuppression compared with the control. The histopathological damage of the target organs was alleviated, and replication of DuCV in the immune organs was significantly inhibited. The treatment also reduced the damage caused by DuCV to the liver and immune function, and increased the level of the DuCV antibody in the blood, thereby improving antiviral activity. Notably, the combination of duck IFN-α and the polyclonal antibody completely blocked DuCV infection after 13 days under the experimental conditions, showing a better inhibitory effect on DuCV infection than single treatments. These results showed that duck recombinant IFN-α and the anti-cap protein antibody can be used as antiviral drugs to clinically treat and control DuCV infection, particularly the vertical transmission of the virus in breeding ducks.

Assessing the evolution of SARS-CoV-2 lineages and the dynamic associations between nucleotide variations.

Despite seminal advances towards understanding the infection mechanism of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), it continues to cause significant morbidity and mortality worldwide. Though mass immunization programmes have been implemented in several countries, the viral transmission cycle has shown a continuous progression in the form of multiple waves. A constant change in the frequencies of dominant viral lineages, arising from the accumulation of nucleotide variations (NVs) through favourable selection, is understandably expected to be a major determinant of disease severity and possible vaccine escape. Indeed, worldwide efforts have been initiated to identify specific virus lineage(s) and/or NVs that may cause a severe clinical presentation or facilitate vaccination breakthrough. Since host genetics is expected to play a major role in shaping virus evolution, it is imperative to study the role of genome-wide SARS-CoV-2 NVs across various populations. In the current study, we analysed the whole genome sequence of 3543 SARS-CoV-2-infected samples obtained from the state of Telangana, India (including 210 from our previous study), collected over an extended period from April 2020 to October 2021. We present a unique perspective on the evolution of prevalent virus lineages and NVs during this period. We also highlight the presence of specific NVs likely to be associated favourably with samples classified as vaccination breakthroughs. Finally, we report genome-wide intra-host variations at novel genomic positions. The results presented here provide critical insights into virus evolution over an extended period and pave the way to rigorously investigate the role of specific NVs in vaccination breakthroughs.

Herpes simplex virus infection

Two of the most prevalent human viruses worldwide, herpes simplex virus type 1 and type 2 (HSV-1 and HSV-2, respectively), cause a variety of diseases, including cold sores, genital herpes, herpes stromal keratitis, meningitis and encephalitis. The intrinsic, innate and adaptive immune responses are key to control HSV, and the virus has developed mechanisms to evade them. The immune response can also contribute to pathogenesis, as observed in stromal keratitis and encephalitis. The fact that certain individuals are more prone than others to suffer severe disease upon HSV infection can be partially explained by the existence of genetic polymorphisms in humans. Like all herpesviruses, HSV has two replication cycles: lytic and latent. During lytic replication HSV produces infectious viral particles to infect other cells and organisms, while during latency there is limited gene expression and lack of infectious virus particles. HSV establishes latency in neurons and can cause disease both during primary infection and upon reactivation. The mechanisms leading to latency and reactivation and which are the viral and host factors controlling these processes are not completely understood.

Identification of an Arylnaphthalene Lignan Derivative as an Inhibitor against Dengue Virus Serotypes 1 to 4 (DENV-1 to -4) Using a Newly Developed DENV-3 Infectious Clone and Replicon.

Dengue virus (DENV) is the most widespread arbovirus, causing symptoms ranging from dengue fever to severe dengue, including hemorrhagic fever and shock syndrome. Four serotypes of DENV (DENV-1 to -4) can infect humans; however, no anti-DENV drug is available. To facilitate the study of antivirals and viral pathogenesis, here we developed an infectious clone and a subgenomic replicon of DENV-3 strains for anti-DENV drug discovery by screening a synthetic compound library. The viral cDNA was amplified from a serum sample from a DENV-3-infected individual during the 2019 epidemic; however, fragments containing the prM-E-partial NS1 region could not be cloned until a DENV-3 consensus sequence with 19 synonymous substitutions was introduced to reduce putative Escherichia coli promoter activity. Transfection of the resulting cDNA clone, plasmid DV3syn, released an infectious virus titer of 2.2 × 102 focus-forming units (FFU)/mL. Through serial passages, four adaptive mutations (4M) were identified, and addition of 4M generated recombinant DV3syn_4M, which produced viral titers ranging from 1.5 × 104 to 6.7 × 104 FFU/mL and remained genetically stable in transformant bacteria. Additionally, we constructed a DENV-3 subgenomic replicon and screened an arylnaphthalene lignan library, from which C169-P1 was identified as exhibiting inhibitory effects on viral replicon. A time-of-drug addition assay revealed that C169-P1 also impeded the internalization process of cell entry. Furthermore, we demonstrated that C169-P1 inhibited the infectivity of DV3syn_4M, as well as DENV-1, DENV-2, and DENV-4, in a dose-dependent manner. This study provides an infectious clone and a replicon for the study of DENV-3 and a candidate compound for future development against DENV-1 to -4 infections. IMPORTANCE Dengue virus (DENV) is the most prevalent mosquito-transmitted virus, and there is no an anti-dengue drug. Reverse genetic systems representative of different serotype viruses are invaluable tools for the study of viral pathogenesis and antiviral drugs. Here, we developed an efficient infectious clone of a clinical DENV-3 genotype III isolate. We successfully overcame the instability of flavivirus genome-length cDNA in transformant bacteria, an unsolved issue for construction of cDNA clones of flaviviruses, and adapted this clone to efficiently produce infectious viruses following plasmid transfection of cell culture. Moreover, we constructed a DENV-3 subgenomic replicon and screened a compound library. An arylnaphthalene lignan, C169-P1, was identified as an inhibitor of virus replication and cell entry. Finally, we demonstrated that C169-P1 exhibited a broad-spectrum antiviral effect against the infections with DENV-1 to -4. The reverse genetic systems and the compound candidate described here facilitate the study of DENV and related RNA viruses.

Demographic and clinical characteristics of human bocavirus-1 infection in patients with acute respiratory tract infections during the COVID-19 pandemic in the Central Province of Sri Lanka

BackgroundHuman bocavirus-1 (hBoV-1) was first detected in respiratory specimens in 2005. Due to high co-infection rates and prolonged shedding of the virus, the pathogenic role of hBoV-1 as a primary causative agent of respiratory infections is still under discussion. This study aimed to determine the prevalence of hBoV-1 infection in patients with acute respiratory tract infections (ARTIs) during the COVID-19 pandemic in the Central Province of Sri Lanka.MethodsA total of 1021 patients (Age 12 days to ≤ 85 years) with ARTI symptoms including fever, cough, cold, sore throat and shortness of breath within first 7 days of the illness were included. The study was carried out at the National Hospital, Kandy, Sri Lanka from January 2021 to October 2022. Respiratory specimens were tested to detect 23 pathogens including hBoV-1 using a real time PCR. Prevalence of hBoV-1 co-infections with other respiratory pathogens and distribution of hBoV-1 infection among different age groups were determined. Moreover, clinical and demographic characteristics of hBoV-1 mono-infection associated ARTI were compared with that of the hBoV-1 co-infections.ResultsRespiratory infections were detected in 51.5% (526/1021) of the patients and of these 82.5% were mono- and 17.1% were co-infections. hBoV-1 was detected in 66 patients and this was the most prevalent respiratory virus associated with 40% co-infections. Of the 66 hBoV-1 positive patients, 36 had co-infections and of these 33 had dual and 3 had triple infections. Most of the hBoV-1 co-infections were identified in children aged 2-<5 years. hBoV-1 co-infections were most frequently detected with respiratory syncytial virus (RSV) and Rhino/ Entero viruses (Rh/EnV). No differences were observed in age, gender and clinical presentations in those with hBoV-1 mono- compared to co-infections. Intensive care admissions were less among hBoV-1 mono-infected than hBoV-1 co-infected patients.ConclusionThis study shows a prevalence of 12.5% for hBoV-1 infections in patients with ARTI. RSV and Rh/EnV were the most common co-infecting pathogens with hBoV-1. Clinical features of hBoV-1 mono-infections were not different to that of the hBoV-1 co-infections. Interactions between hBoV-1 and other respiratory pathogens need investigation to identify the role of hBoV-1 in clinical severity of co-infections.

Uptake rates and attitudes to influenza and COVID-19 vaccination in pregnancy - a prospective cohort study.

Influenza and COVID-19 are highly prevalent RNA viruses. Pregnancy increases the frequency of severe maternal morbidity and mortality associated with these viruses. Vaccination plays an important role in protecting pregnant women and their infants from adverse outcomes. In this prospective study, we aimed to determine the vaccination uptake rate for influenza and COVID-19 in a pregnant population and to explore reasons why women remained unvaccinated. A prospective cohort study was conducted over a two-week period in December 2022 in the National Maternity Hospital, Dublin. There were 588 women surveyed over the 2-week period. Overall, 377 (57%) were vaccinated that year for seasonal influenza, a significant rise from 39% in a similar study in 2016. The majority (n = 488, 83%) of women reported receiving at least one COVID-19 vaccine. However only 132 (22%) received a COVID-19 vaccine in pregnancy, despite 76% (n = 466) stating they would be happy to receive it. Factors such as age, obesity, co-morbidities, ethnic group, and type of antenatal care received were shown to influence vaccination rates. We recommend that the importance of vaccination be stressed regularly to eligible patients at their antenatal clinic visits and where possible combining influenza/COVID-19 vaccination on the same day to improve uptake.