Viral Load Research Articles

Initiation of Dolutegravir vs Efavirenz on Viral Suppression and Retention at 6-months: A Regression Discontinuity Design

Background: In 2019, South Africa’s Antiretroviral Therapy (ART) Treatment Guidelines replaced efavirenz with dolutegravir in first-line ART. Setting: We assessed the impact of this national guideline change on retention and viral suppression in the Themba Lethu Clinical Cohort, Johannesburg, South Africa. We applied a regression discontinuity design in a prospective cohort study of 1654 adults living with HIV initiating first-line ART within 12 months (±12 months) of the guideline change. Methods: We compared outcomes in individuals presenting just before and after the guideline change and estimated intention-to-treat effects on initiating a dolutegravir- vs efavirenz-based regimen. Primary outcomes were retention and viral suppression. Participants were defined as retained in care if a visit took place within +3-months of the 6-month endpoint. Viral suppression was defined as having a viral load < 1000 copies/mL 3-months prior to and up to 6-months after the 6-month endpoint. Results: The 2019 guideline change led to an increase in uptake of dolutegravir. We noted a 26.6 percentage point increase in the proportion initiating dolutegravir (95% Confidence Interval (CI): 14.1, 38.6). We saw a small increase in viral suppression (Risk Difference (RD): 7.4 percentage points; 95% CI: -1.6, 16.5) and no change in retention (RD: -1.7 percentage points; 95% CI: -13.9, 10.5) at 6 months, though our findings were imprecise. Conclusion: Our estimates suggest early uptake of the revised treatment guidelines after implementation. Despite this, there was no meaningful change in viral suppression and retention rates at 6-months.

First detection of atypical porcine pestivirus in piglets affected by congenital tremor in Poland.

Congenital tremors are neurological disorders of newborn piglets that may lead to serious health consequences, including increased mortality. Many reports have indicated that atypical porcine pestivirus (APPV), first identified in 2015, is a possible cause of this condition. In different countries, APPV was detected in farms affected by piglets' congenital tremors. There is a lack of data regarding the presence of this virus in Poland. However, swine veterinarians report outbreaks of congenital tremor with unestablished aetiology nationwide. Therefore, this study aimed to verify the presence of APPV in piglets with congenital tremors in Poland. Samples of blood (2), faecal swabs (7), brain (7), cerebellum (5), spinal cord, (7) lymph nodes (7), tonsil (7), thymus (6), tongue (7), heart (7), lung (7) and liver (7) were collected from piglets. Form sows' blood (5) and oral fluid (3, pooling samples) were collected. All samples have been derived from a commercial breeding farm reporting a case of congenital tremor and subjected to the qPCR via commercial kit (EXOone Atypical Porcine Pestivirus, Exopol, Spain). Six out of seven piglets tested positive for APPV, with the highest viral loads detected in the cerebellum and tonsils. All samples from sows were negative, emphasising the virus's specificity to piglets. To the authors' knowledge, this is the first report confirming APPV's presence in Poland. Given the potentially significant impact of APPV infections on swine health and production economics, further research evaluating the epidemiology and pathogenicity of APPV, as well as identifying preventive measures, is sorely needed.

Pharmaco-virological Outcomes and Genotypic Resistance Profiles Among Children and Adolescents Receiving a Dolutegravir-Based Regimen in Togo.

Few data are available on the real-world efficacy of receiving tenofovir-lamivudine-dolutegravir (-DTG) as human immunodeficiencyvirus (HIV) treatment, particularly among young people in West Africa. Here, we evaluated pharmaco-virological outcomes and resistance profiles among Togolese children and adolescents. A cross-sectional study was conducted in Lomé, Togo, enrolling antiretroviral-treated people with HIV aged from 18 months to 24 years. Plasma HIV-1 viral load and antiretroviral concentrations were measured. Next-generation sequencing of protease, reverse transcriptase (RT), and integrase was performed on all samples with viral loads >200 copies/mL. Drug resistance mutations (DRMs) were identified and interpreted using the ANRS-MIE algorithm. 264 participants were enrolled (median age, 17 years); 226 received a DTG-based regimen for a median of 20.5 months. Among them, there was virological suppression at the 200-copies/mL threshold in 80.0% of the participants. Plasma DTG concentrations were adequate (ie, >640 ng/mL), suboptimal, and below the limit of quantification in 74.1%, 6.7%, and 19.2% of participants receiving DTG, respectively. Overall, viruses resistant to any of nucleoside RT inhibitors, non-NRTIs, and protease inhibitors were found in 52%, 66%, and 1.6% of participants, respectively. A major integrase inhibitor DRM was observed in 9.4% (n = 3/32; R263K, E138A-G140A-Q148R, and N155H) of participants with a viral load >200 copies/mL. These first findings in a large series of adolescents in a low-income country showed a good virological response of 80% and the presence of an integrase DRM in 9.4% of virological failures, supporting the need to monitor DTG drug resistance to reduce the risk of resistance acquisition.

Impact of HBV serological status on HIV virological efficacy of two-drug antiretroviral regimens: A retrospective observational study on virologically suppressed people with HIV switching to lamivudine/dolutegravir.

This study aimed to evaluate the HIV virological efficacy of two-drug regimens (2DR) with lamivudine (3TC) and dolutegravir (DTG) in people with HIV (PWH), classified by their hepatitis B virus (HBV) serological status. Specifically, it explored whether isolated anti-hepatitis B core (anti-HBc) positivity impacts virological outcomes. A retrospective observational study was conducted at Fondazione Policlinico Universitario Agostino Gemelli IRCCS, enrolling 606 virologically suppressed (HIV-RNA < 50 copies/mL) PWH who switched to a 2DR regimen with 3TC/DTG. Participants were categorized into four groups based on their HBV serological status: hepatitis B surface antibody (HBsAb)-positive/hepatitis B core antibody (HBcAb)-positive, HBsAb-negative/HBcAb-negative, HBsAb-positive/HBcAb-negative, and isolated HBcAb positivity. Viral failure (VF) was defined as two consecutive HIV viral loads above 50 copies/mL or a single HIV viral load above 1000 copies/mL, and viral blips (VBs) as a single HIV-RNA measurement between 50 and 200 copies/mL followed by suppression. During 2216.4 patient-years of follow-up (PYFU), we observed 30 VFs (1.3 per 100 PYFU) and 63 VBs (2.9 per 100 PYFU). No statistically significant differences in VF or VB were noted between the serological groups. Additionally, no significant alanine aminotransferase (ALT) flares or HBV-DNA breakthroughs were observed, with HBV-DNA remaining undetectable throughout. The study supports the virological efficacy of 3TC/DTG-based 2DR in PWH, regardless of HBV serological status. Isolated anti-HBc positivity did not influence virological outcomes independently. Larger studies are warranted to further investigate HIV-HBV interactions in this context.

Development of HIV Drug-Resistance Mutations and Antiretroviral Efficacy Among Vietnamese Patients After Failure of 5-Year First-Line Therapy.

The emergence of drug-resistant mutations in human immunodeficiency virus (HIV) over time presents a challenge to treatment. We describe the development of drug-resistance mutations and ART efficacy reduction in Vietnamese patients with failure of first-line ART during a 5-year period. This is a 5-year observational cohort study with HIV viral loads of patients evaluated annually for 5 years (2017-2022) at the hospitals in Vietnam. Patients with a viral load ≥ 1000 copies/mL were subjected to identifying mutations in reverse transcriptase, protease, and integrase to evaluate HIV resistance and the efficacy of ART. After 5 years of monitoring the HIV load of 2932 patients on ART, 75 (2.56%) patients had concurrent virological failure at all 5 years. In 2017, only 2/75 HIV strains possessed Protease Inhibitor (PI) resistance mutations, while 75/75 HIV strains had both Nucleoside Reverse Transcriptase Inhibitors (NRTIs) and Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs) resistance mutations. Only four PI resistance variants were found, while 40 and 32 mutations were resistant to NRTIs and NNRTIs. After 5 years, the number of HIV PI resistance mutations had increased to 14, with 13 new mutations emerging. There were six novel mutations associated with resistance to NRTIs, NNRTIs, and the proportion of preexisting mutations increased from 1.3% to 13.3%. Furthermore, HIV sensitivity to ART decreased from 2.7% to 18.6%. After 5 years, HIV had increased resistance mutations to PIs, NRTIs, and NNRTIs, with PI resistance mutations increasing the most rapidly, and the decrease in HIV sensitivity to PIs was higher than that to NRTIs and NNRTIs.

Reduced peri-pubertal bone density accrual among Zimbabwean males living with HIV: a longitudinal study.

To investigate bone density accrual over 1 year among peripubertal children living with HIV (CWH) compared to children without infection (CWOH); and risk factors associated with bone density accrual among CWH. A prospective cohort study in urban Zimbabwe. CWH on antiretroviral therapy aged 8-16 years, and CWOH, frequency-matched by age were recruited in Zimbabwe. Z-scores for height-adjusted total-body less-head bone mineral content for lean mass (TBLH-BMCLBM) and size-adjusted lumbar spine bone mineral apparent density (LS-BMAD) were calculated from dual X-ray absorptiometry (DXA) scan measurements. Linear regression compared bone density accrual by HIV status. Of 609 participants, 492 (80.7%) completed a follow-up visit (50.2% male, 49.6% CWH). Mean baseline age was 12.5 years. More female CWH than CWOH were in Tanner stages I/II at baseline. Bone density accrual (Δ) adjusted for age, Tanner stage and baseline DXA Z-score was less in male CWH than male CWOH {adjusted mean (95% confidence interval (CI)] ΔLS-BMAD Z-score -0.14 (-0.25 to -0.02) vs. 0.01 (-0.09 to 0.12), P = 0.020, and ΔTBLH-BMCLBMZ-score -0.19 (-0.33 to -0.04) vs. 0.07 (-0.07 to 0.20), P = 0.015}, but similar in females with and without HIV [ΔLS-BMAD Z-score 0.05 (-0.07 to 0.17) vs. -0.01 (-0.09 to 0.07), P = 0.416, and ΔTBLH-BMCLBMZ-score 0.08 (-0.07 to 0.22) vs. -0.03 (-0.12 to 0.07), P = 0.295]. Viral load greater than 1000 copies/ml and tenofovir disoproxil fumarate use were associated with less gain in LS-BMAD Z-score among males, whereas Tanner stage IV and V were associated with greater gains in LS-BMAD and TBLH-BMCLBMZ-scores among CWH. Among males only, CWH had impaired bone accrual, associated with high viral load and tenofovir use. Bone density gains were greater in later puberty among CWH suggesting potential to correct deficits.

Rapid restoration of potent neutralization activity against the latest Omicron variant JN.1 via AI rational design and antibody engineering

The rapid evolution of the viral genome has led to the continual generation of new variants of SARS-CoV-2. Developing antibody drugs with broad-spectrum and high efficiency is a long-term task. It is promising but challenging to develop therapeutic neutralizing antibodies (nAbs) through in vitro evolution based on antigen-antibody binding interactions. From an early B cell antibody repertoire, we isolated antibody 8G3 that retains its nonregressive neutralizing activity against Omicron BA.1 and various other strains in vitro. 8G3 protected ACE2 transgenic mice from BA.1 and WA1/2020 virus infection without adverse clinical manifestations and completely cleared viral load in the lungs. Similar to most IGHV3-53 antibodies, the binding sites of 8G3 and ACE2 largely overlap, enabling competition with ACE2 for binding to RBD. By comprehensively considering the binding free energy changes of the antigen-antibody complexes, the biological environment of their interactions, and the evolutionary direction of the antibodies, we were able to select 50 mutants. Among them, 11 were validated by experiments showing better neutralizing activities. Further, a combination of four mutations were identified in 8G3 that increased its neutralization potency against JN.1, the latest Omicron mutant, by approximately 1,500-fold, and one of the mutations led to an improvement in activity against multiple variants to a certain extent. Together, we established a procedure of rapid selection of neutralizing antibodies with potent SARS-CoV-2 neutralization activity. Our results provide a reference for engineering neutralizing antibodies against future SARS-CoV-2 variants and even other pandemic viruses.

Usutu virus-induced meningoencephalitis in immunocompetent mice is characterized by the recruitment of mononuclear cells and a proinflammatory T helper 1 response.

Usutu virus (USUV) is an arbovirus and has emerged as a potential cause of encephalitis in humans and other vertebrates. The increasing detection of USUV in mosquitoes and birds across Africa and Central Europe, along with the lack of specific treatments or vaccines for many encephalitic orthoflaviviruses, underscores the need for focused research. In this study, we developed a USUV infection model in immunocompetent C57BL/6 mice (8-12 weeks old) to characterize disease development and associated inflammatory mechanisms. Mice were intracranially infected with 104 PFU of USUV, leading to neurological symptoms such as hunched posture, paralysis, conjunctivitis, and eventual death by day 6 post-infection. Meningeal cell infiltration and microglia activation were most prevalent in mouse brains; however, neuronal loss was not observed at the peak of the disease, which coincided with increased viral load and leukocyte infiltration. The immune response in the brain was marked by the systematic recruitment and activation of macrophages, neutrophils, and T lymphocytes. A noticeable shift was seen in CD4+ T cells toward T helper 1 (Th1) polarization, which corroborates a massive increase in the expression of Th1-associated cytokines and chemokines at the peak of infection, indicative of an augmented proinflammatory state. Additionally, a rise in regulatory T cells was observed, peaking on day 6 post-infection. These findings highlight the dynamic nature of the host response to USUV infection, enhance our understanding of the disease pathogenesis, and address the scarcity of immunocompetent experimental models for the investigation of neglected emerging flaviviruses.IMPORTANCEMosquito-borne viruses, including USUV, are maintained in nature through complex cycles involving arthropod vectors and vertebrate hosts. A comprehensive understanding of USUV biology and host-pathogen interactions is crucial for developing effective treatments, which necessitates reliable experimental models (G. J. Sips, J. Wilschut, and J. M. Smit, Rev Med Virol 22:69-87, 2012, https://doi.org/10.1002/rmv.712; T. C. Pierson and M. S. Diamond, Nat Microbiol 5:796-812, 2020, https://doi.org/10.1038/s41564-020-0714-0). The establishment of a USUV infection model in immunocompetent adult mice brings new perspectives on the inflammatory component of viral encephalitis, which is difficult to study in mice lacking antiviral interferon responses. Moreover, USUV is an emerging viral disease lacking therapeutic and preventive measures. The interplay of USUV pathogenesis and the host's immune response indicates that lymphocytes and monocytes participate in USUV infection in this model and could be explored in search of treatments targeting immunopathogenic processes triggered by infection.

Microfluidic digital focus assays for the quantification of infectious influenza virus.

Quantifying infectious virus is essential for vaccine development, clinical diagnostics, and infectious disease research, but current assays are constrained by long turnaround times, high costs, and laborious procedures. To address these limitations, we present a digital focus assay employing an array of independent nanoliter cell cultures. The microfluidic platform allows cells in each nanowell to be inoculated with virus, followed by oil discretization to prevent cross-contamination. After incubation, infected cells are visualized through immunofluorescence staining, and a binary map of wells positive for viral antigen is generated by automated image analysis, allowing infectious viral titer to be calculated by statistical analysis. The platform requires significantly smaller sample and reagent volumes than conventional focus assays while enhancing assay automation and endpoint time flexibility. The technology is applied to the quantification of infectious influenza A using both model virus and clinical specimens, demonstrating the digital platform as an accurate, rapid, cost-effective, and convenient tool for viral load quantification with broad utility in clinical, pharmaceutical, and research applications.

Interleukin-21 and anti-α4β7 dual therapy during ART promotes immunological and microbiome responses in SIV-infected macaques.

Despite combination antiretroviral therapy (ART), HIV causes persistent gut barrier dysfunction, immune depletion, and dysbiosis. Further, ART interruption results in reservoir reactivation and rebound viremia. Both IL-21 and anti-α4β7 improve gut barrier functions, and we hypothesized combining them would synergize as a dual therapy to improve immunological outcomes in SIV-infected rhesus macaques (RMs). We found no significant differences in CD4+ T-cell reservoir size by intact proviral DNA assay. SIV rebounded in both dual-treated and control RMs following analytical therapy interruption (ATI), with time to rebound and initial rebound viremia comparable between groups; however, dual-treated RMs showed slightly better control of viral replication at the latest time points post-ATI. Additionally, following post-ATI, dual-treated RMs showed immunological benefits, including T-cell preservation and lower PD-1+ central memory T-cell (TCM) frequency. Notably, PD-1+ TCMs were associated with reservoir size, which predicted viral loads (VLs) post-ATI. Finally, 16S rRNA sequencing revealed better recovery from dysbiosis in treated animals, and the butyrate-producing Firmicute Roseburia predicted PD-1-expressing TCMs and VLs after ATI. PD-1+ TCMs and gut dysbiosis represent mechanisms of HIV persistence and pathogenesis, respectively. Therefore, combining IL-21 and anti-α4β7 may be an effective therapeutic strategy to improve immunological outcomes for people with HIV.

Do Nurse Practitioners Deliver? A Retrospective Self-audit Comparing Nurse Practitioner Care for People With HIV in Australia to Screening and Monitoring Guidelines.

In Australia, nurse practitioners (NPs) provide care to people with HIV (PWH) in hospital and community settings. We describe a national audit evaluating NP care for PWH, assessing adherence to 2 HIV monitoring guidelines. Five NPs conducted a retrospective case note self-audit. Deidentified data were collected, pooled, and analyzed using Microsoft Excel and compared with HIV monitoring guideline targets. The review was undertaken for 212 NP patients, the majority being cisgendered men (86%), ages 45-49 years, identifying as gay (65%). The majority (95%) of PWH were on an appropriate HIV treatment, meeting the United Nations Programme on HIV/AIDS target of 95%. HIV viral load testing was current for 211 (99%) individuals. Of 138 individuals eligible for cardiovascular screening, 84 (60%) were screened, below a guideline target of 90%. Compliance with HIV monitoring guidelines exceeded targets in most areas. Our audit demonstrates that NPs provide effective and guideline compliant HIV care to PWH in Australia.

The immunogenicity of PRV ΔgE/TK/UL49.5 three-gene-deleted vaccine in mice

BackgroundPseudorabies (PR) caused by the re-emerging of pseudorabies virus (PRV) variant has outbroken among PRV vaccine immunized swine in many pig farms, which has caused serious social and economic consequences since the end of 2011. The PRV UL49.5 protein can inactivate the transporter associated with antigen processing (TAP), thereby downregulating the cell surface expression of swine leukocyte antigen class I (SLA-I) to evade host immune surveillance.MethodsIn this study, based on the PRV ΔgE/TK strain, PRV ΔgE/TK/UL49.5 triple gene deletion strain was constructed through homologous recombination and deletion of the PRV UL49.5 gene by the Cre-LoxP system. Its growth curve and effect on SLA-I transcription level were determined. Preliminary studies were carried out on serum neutralizing antibody levels, IFN-γ and IL-4 cytokines levels in mice immunized with PRV ΔgE/TK/UL49.5, and the viral load and challenge protection in mice tissues after challenge.ResultsThe growth characteristics of PRV ΔgE/TK/UL49.5 strain were similar to those of PRV ΔgE/TK strain. The level of SLA-I was returned to normal after the deletion of PRV UL49.5 gene. The immunization of PRV ΔgE/TK/UL49.5 did not affect the weight gain of mice. Immunized mice could induce high levels of serum neutralization antibodies and immune cytokines, including IFN-γ and IL-4, which could provide complete protection against virulent PRV challenge. No obvious pathological damage was observed in lung, brain and trigeminal ganglion of mice immunized with PRV ΔgE/TK/UL49.5, and the tissue viral load was the lowest.ConclusionsPRV ΔgE/TK/UL49.5 strain can induce enhanced immunogenicity and had the potential to be used as a candidate strain.

Modeling suggests SARS-CoV-2 rebound after nirmatrelvir-ritonavir treatment is driven by target cell preservation coupled with incomplete viral clearance.

Nirmatrelvir-ritonavir is an effective treatment for SARS-CoV-2. In a subset of individuals treated with nirmatrelvir-ritonavir, the initial reduction in viral load is followed by viral rebound once treatment is stopped. We show that the timing of treatment initiation with nirmatrelvir-ritonavir may influence the risk of viral rebound. Nirmatrelvir-ritonavir stops viral growth and preserves target cells but may not lead to full clearance of the virus. Thus, once treatment ends, if an effective adaptive immune response has not adequately developed, the remaining virus can lead to rebound. Our results provide insights into the mechanisms of rebound and can help develop better treatment strategies to minimize this possibility.

Isolation, genetic, and biological characterization of human adenovirus type 55 positive isolates from Wuhan, China.

Human adenovirus (HAdV) infection causes acute respiratory diseases in immunocompetent individuals worldwide. Infections by HAdV-55, one of the important pathogens leading to respiratory tract infections, often develop into pneumonia and are frequently associated with outbreaks in military camps and schools. We studied 186 HAdV-55-positive nasopharyngeal swab samples that were collected from patients with respiratory infection in Wuhan, China, from 2018 to 2019. Fifteen samples with high viral loads were selected for viral isolation and cultured with MRC-5 cells. These strains were then whole-genome sequenced to investigate their genetic characteristics by phylogenetic analyses. We then selected three HAdV-55 strains to quantify viral replication and further assessed the pathogenic characteristics of one strain in Syrian hamsters and BALB/c nude mice. HAdV-55-174 exhibited the highest replication ability in cultured cells compared to other strains, so this strain was selected for further investigation. Although the hamsters and mice were not so susceptible to HAdV-55-174 infection, viral loads were detected in the lungs and tracheas of the animal models, and persistent HAdV-55-174 replication was only observed in BALB/c nude mice. Histopathological lesions, including a widened alveolar septum and inflammatory cell infiltration, were observed in the lungs and tracheas of HAdV-55-174 infected animals. We isolated and characterized the HAdV-55 strains circulating in Wuhan from 2018 to 2019, which may be meaningful for further studies on HAdV-55 infection and pathogenesis.

Temporal Dynamics of Immune Response Signalling in Largemouth Bass (Micropterus salmoides) Infected With Largemouth Bass Virus.

The largemouth bass virus (LMBV) significantly impacts Chinese largemouth bass aquaculture. The molecular mechanisms regulating LMBV virulence and the gene responses stimulated in the host during infection remain unclear. This study investigates the transcriptional dynamics and signalling pathways activated during the immune response to LMBV by analysing the transcriptome of head kidney tissues at 1, 4, 7, and 28 days post-infection (dpi) using RNA sequencing. Histopathological and viral load analyses indicated early tissue disruption, followed by extensive recovery by 28 dpi. Analysis of differentially expressed genes (DEGs) and weighted gene co-expression network analysis (WGCNA), combined with Venn analysis of samples at 1, 4, and 7 dpi, identified significant and common genes. Early infection triggered robust innate immunity through activation of the RIG-I like receptor and cGAS-STING signalling pathways, which activated type I interferons (IFNs) and interferon-stimulated genes (ISGs). Later stages indicated activation of adaptive immune responses. Validation of randomly selected genes via RT-qPCR confirmed the RNA-seq results, showing consistent expression patterns. This comprehensive study offers new insights into the sustained innate and adaptive immune responses to LMBV.

Conventional and antibody-enhanced DENV infection of human macrophages induces differential immunotranscriptomic profiles.

Dengue virus (DENV) is a mosquito-borne flavivirus which coexists as four genetically and immunologically distinct serotypes (DENV-1 to -4). In secondary heterologous DENV infection, pre-existing immunity is believed to contribute to severe disease through antibody-dependent enhancement (ADE). Although the elevated pathology observed in ADE conditions has been described, the cell-intrinsic mechanisms governing this process remain unclear. Using single-cell RNA sequencing (scRNAseq), we investigated the transcriptomic profiles of human monocyte-derived macrophages infected by DENV-2 in ADE compared to conventional infection conditions. Unsupervised analysis of scRNAseq data enabled the identification of two distinct cell populations in a heterogeneous cell culture, likely representing infected and bystander/uninfected cells. Differential gene expression and ingenuity pathway analyses revealed a number of significantly upregulated and downregulated genes and gene networks between cells infected by ADE compared to conventional infection. Specifically, these pathways indicated mechanisms such as suppressed interferon signaling and inflammatory chemokine transcription in cells infected via ADE. Further analysis revealed that transcriptomic changes were independent of viral RNA within infected cells, suggesting that the observed changes are reflective of cell-intrinsic responses and not simply a function of per-cell viral burden. The interpreted "bystander" cell population also demonstrated distinct profiles in ADE conditions, indicating an immunologically activated phenotype enriched for the expression of gene networks involved with protein translation, cytokine production, and antigen presentation. Together, these findings support the concept that DENV infection via ADE induces a qualitatively different transcriptomic response in infected cells, contributing to our understanding of ADE as a mechanistic driver of disease and pathogenesis.IMPORTANCEDengue virus (DENV) is a mosquito-borne human pathogen with a significant and growing global health burden. Although correlates of severe dengue disease are poorly understood, pre-existing immunity to DENV has been associated with severe disease risk and known to contribute to an alternative route of viral entry termed antibody-dependent enhancement (ADE). Using single-cell RNA sequencing, we identified distinct transcriptomic processes involved in antibody-mediated DENV entry compared to conventional receptor-mediated entry. These data provide meaningful insight into the discrete processes contributing to DENV pathogenesis in ADE conditions.

Drug resistance testing at regimen failure in individuals diagnosed with HIV-1 between 2010 and 2018 in Israel.

Assess virological failures, analyze the results of resistance testing (RET), and investigate factors associated with acquired drug resistance mutations (aDRM). A retrospective longitudinal cohort study. Virological failures (viral load >50 copies/ml) from a cohort of 1130 individuals, diagnosed with HIV-1 in 2010-2018 and followed up until 2020, were included. Demographic, clinical, and virological data were collected. A piecewise exponential additive mixed model was employed to estimate the association of various factors with aDRM. Only 82 individuals had virological failure, 20/82 had multiple virological failures. The majority of virological failures (77%) were men, 48% were Israeli-born,79% were diagnosed in 2010-2014. Only 18% initiated with second-generation integrase-inhibitor (INI) based regimens. Although no baseline differences were identified between those with single and multiple virological failures, the latter had lower CD4+ levels before first virological failure. NRTI M184IV and INI N155H were identified in more than 10% of the cases. In those with additional failures, INI N155H was more prominent in cases with subtype B compared to those with non-B subtypes (P = 0.039). Diagnoses with CD4+ cell count less than 200 cells/μl and AIDS [hazard ratio = 3.46, 95% confidence interval (95% CI): 1.51-7.92, P = 0.003], second-generation INI at the first virological failure (HR = 0.32, 95% CI: 0.11-0.91, P = 0.033), and RET at baseline (hazard ratio = 0.34, 95% CI: 0.13-0.86, P = 0.022) had a significant and persistent relative effect on aDRM. The risk for aDRM is reduced in those who are treated with second-generation INI-based regimens. Diagnosis with low CD4+ cell counts and AIDS is associated with detection of aDRM.

Marek's disease virus-1 unique gene LORF1 is involved in viral replication and MDV-1/Md5-induced atrophy of the bursa of Fabricius.

Marek's disease virus (MDV), an alphaherpesvirus, causes severe immunosuppression and T cell lymphomas in chickens, known as Marek's disease (MD), an economically important poultry disease primarily controlled by vaccination. Importantly, it also serves as a comparative model for studying herpesvirus-induced tumor formation in humans. MDV encodes more than 100 genes, most of which have unknown functions. MDV LORF1 is unique to serotype I MDV (MDV-1), lacking homologs in other herpesviruses, and has not been explored yet. To this end, an infectious bacterial artificial chromosome (BAC) harboring the complete genome of the MDV-1 very virulent strain Md5 was generated, and the rescued rMd5 maintained biological properties similar to the parental virus both in vitro and in vivo. Subsequently, rMd5ΔLORF1, a recombinant Md5 virus deficient in pLORF1 expression, was generated by a frameshift mutation in the LORF1 gene. Chickens infected with rMd5ΔLORF1 exhibited a lower mortality rate and delayed bursal atrophy than those infected with the parental rMd5 and the revertant virus (rMd5-reLORF1). Consistently, viral loads of rMd5ΔLORF1 were obviously lower than those of rMd5 or rMd5-reLORF1 in the bursa, but not in the spleen. Importantly, we found that pLORF1 deficiency impairs viral replication in bursal B cells. Furthermore, we showed that pLORF1 associated with the cellular membrane, interacted with MDV structural proteins, and exhibited punctate colocalization with tegument or capsid proteins in the cytoplasm. Taken together, this study demonstrates for the first time that the MDV-1 unique gene LORF1 is involved in MDV-induced bursal atrophy but not in tumor formation.

Viral Load of Human Papillomavirus (HPV) During Pregnancy and Its Association With HPV Vertical Transmission.

Little is known on the dynamics of human papillomavirus (HPV) viral load during pregnancy and on the impact of viral load on HPV vertical transmission. We described viral loads for several genotypes during pregnancy and analyse its association with vertical transmission. Data were analysed from the HERITAGE study, a cohort of pregnant women recruited between 2010 and 2016 in three centres in Canada. Vaginal samples were collected at the first and third trimesters of pregnancy, placental samples were collected at birth, and conjunctival, oral, pharyngeal, and genital samples were collected in children at birth and 3 months were tested for HPV DNA and viral load by Linear Array essay. The association between viral load and vertical transmission was measured using logistic regression. Odd ratios (ORs) and their 95% Confidence intervals (CI) were adjusted for age of the mother. We included women in the cohort infected with the 13 most common genotypes during pregnancy (n = 287). A decrease in HPV viral load was observed during pregnancy (median difference between the third and first trimester of pregnancy = -0.005 copies/cell [p < 0.05]). Women with more than 2 HPV copies/cell (compared to those with ≤ 2 copies) at first trimester had a statistically significant higher risk of vertical transmission (adjusted OR = 6.41; 95% CI: 1.10-37.34 for any genotypes and OR = 17.17; 95% CI: 1.18-250.28 for HPV-16). Viral load values analysed continuously or categorized with different cut-offs showed comparable results. HPV viral load varied during pregnancy and was strongly associated with HPV vertical transmission. The results provide a better understanding of risk factors associated with vertical transmission.

Mother-child dyads living with HIV in the Western Cape, South Africa: Undetectable = Undetectable?

Globally, children living with HIV continue to lag behind UNAIDS targets for viral suppression (VS). Because studies with linked mother-child data are limited, we describe VS and associated factors among young children in a setting with early infant HIV testing (at birth, age 10 weeks and 6 months) and early protease inhibitor-based first-line antiretroviral therapy (ART). We analysed routinely collected mother-child data for children living with HIV born 2018-2022 in Western Cape province, South Africa (followed through mid-2023). We assessed associations between child and maternal viral load (VL) results at 12 and 24 months after child ART start using logistic regression, adjusted for child sex, birthyear, severity of child immunodeficiency at ART start, maternal age and timing of maternal HIV diagnosis. Among 2219 children living with HIV; 30% were diagnosed at birth (≤7 days), 41% before age 1 year (8-365 days) and 29% at age >1 year. Overall, 5% (n = 112/2219) of children died, a third of whom had not started ART; 90% of children (n = 1990) started ART, at median age 5 months (IQR 1-16). Median follow-up from ART start was 26 months (IQR 14-40). Among children with available VL at 12 months (n = 853/1582), 24 months (n = 614/1129) and 36 months (n = 350/658) after ART start, 36%, 43% and 48% were virally suppressed, respectively (VL<100 copies/ml). VS among children at 12 and 24 months was more likely if maternal VL was <100 versus ≥100 copies/ml at 12 months (adjusted odds ratio [aOR] = 3.5; 95% CI 1.9-6.5) and 24 months (aOR = 6.1; 95% CI 2.8-13.1) after child ART start. Children with no/mild versus advanced/severe immunodeficiency at ART start were more likely to achieve VS at 12 months (aOR = 2.3; 95% CI 1.3-4.2) but not at 24 months. Eligible children with missing VL at 24 months (39%) were more likely to have gaps in care of >6 months than those with VL≥100 or VL<100 copies/ml (84% vs. 28% vs. 14%, respectively; p<0.001). Less than half of children on ART achieved VS, and children were more likely to achieve VS if their mothers were also virally suppressed. Significant efforts are needed to support mother-child dyads to achieve optimal VS.