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41 result(s) for "McCurdy, Lewis"
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Decoding respiratory syncytial virus morphology: distinct structural and molecular signatures of spherical and filamentous particles
Respiratory syncytial virus (RSV) is a pleomorphic enveloped virus that buds as both spherical and filamentous particles. The determinants of RSV particle morphology and the roles of these forms in transmission and pathogenicity are not clearly defined, owing to a complex interplay of viral proteins and host factors that remains poorly understood. To further characterize RSV morphology, we developed a sucrose gradient velocity sedimentation method to separate spherical and filamentous virions. Fluorescence microscopy and electron microscopy (EM) confirmed two distinct peaks containing predominantly spherical or filamentous particles, respectively. Notably, EM images revealed a distinctive “honeycomb” pattern on the RSV envelope, suggesting an ordered lattice of glycoproteins on the virion surface. Biochemical analyses of viral protein and lipid content showed that filamentous particles contained higher levels of uncleaved fusion protein F0 and exhibited distinct phospholipid profiles compared to spherical particles. Both forms were enriched in cholesterol and phospholipids characteristic of lipid rafts, consistent with the idea that RSV buds from lipid raft microdomains. This enrichment in raft lipids is linked to cell-to-cell fusion (syncytium) formation and virion assembly. Quantitative real-time PCR analysis indicated a high particle-to-PFU ratio (~4:1), meaning only about one in four RSV virions was infectious. Spherical particles contained on average ~3 genomic RNA copies per virion, whereas filamentous particles contained ~2 copies. These data reveal several structural and compositional differences between RSV particle morphologies that may influence viral pathogenesis, and they provide a foundation for new antiviral approaches targeting virion assembly and morphology.
Host RhoA Signaling Controls Filamentous vs. Spherical Morphogenesis and Cell-to-Cell Spread of RSV via Lipid Raft Localization: Host-Directed Antiviral Target
Respiratory syncytial virus (RSV) is a major human respiratory pathogen, particularly affecting infants, the elderly, and immunocompromised individuals. RSV exists in both spherical and filamentous forms, with the filamentous morphology associated with enhanced infectivity and cell-to-cell spread. Here, we demonstrate that RhoA, a small GTPase involved in cytoskeletal regulation, is essential for filamentous RSV morphogenesis through its role in organizing lipid raft microdomains. Rhosin, a selective RhoA inhibitor developed through structure-guided screening, disrupts GEF–RhoA interactions to block RhoA activation. The pharmacological inhibition of RhoA with Rhosin significantly reduced filamentous virion formation, disrupted RSV fusion (F) protein colocalization with lipid rafts, and diminished cell-to-cell fusion, without affecting overall viral replication. Scanning electron microscopy revealed that Rhosin-treated infected HEp-2 cells exhibited fewer and shorter filamentous projections compared to the extensive filament formation seen in untreated cells. β-galactosidase-based fusion assays confirmed that reduced filamentation corresponded with decreased cell-to-cell fusion. The biophysical separation of RSV spherical and filamentous particles by sucrose gradient velocity sedimentation, coupled with fluorescence and transmission electron microscopy, showed that Rhosin treatment shifted virion morphology toward spherical forms. This suggests that RhoA activity is critical for filamentous virion assembly, which may enhance viral spread. Immunofluorescence microscopy using lipid raft-selective dyes (DiIC16) and fusion protein-specific antibodies revealed the strong co-localization of RSV proteins with lipid rafts. Importantly, the pharmacological inhibition of RhoA with Rhosin disrupted F protein partitioning into raft domains, underscoring the requirement for intact lipid rafts in assembly. These findings highlight a novel role for host RhoA signaling in regulating viral assembly through raft microdomain organization, offering a potential target for host-directed antiviral intervention aimed at altering RSV structural phenotypes and limiting pathogenesis.
Cabotegravir + Rilpivirine Long-Acting Injections for HIV Treatment in the US: Real World Data from the OPERA Cohort
Introduction The first complete long-acting antiretroviral therapy (ART) regimen, cabotegravir + rilpivirine long-acting (CAB + RPV LA) injectable, was approved in the US for HIV-1 treatment in individuals on a stable antiretroviral regimen with a viral load < 50 copies/mL, no treatment failure history, and no resistance to either cabotegravir or rilpivirine. We describe injection schedule adherence and virologic effectiveness of CAB + RPV LA in routine clinical care in the US. Methods From the OPERA ® cohort, all adults with HIV who received their first CAB + RPV LA injection and ≥ 1 continuation injections between 21 January 2021 and 15 March 2022 were included. The injection target date was updated monthly and set to the same date of the month as the previous injection. Continuation injections administered within 7 days before or after the target date were considered on time, as per the label. Virologic undetectability (viral load < 50 copies/mL), suppression (viral load < 200 copies/mL), and confirmed virologic failure (2 consecutive viral loads ≥ 200 copies/mL or 1 viral load ≥ 200 copies/mL followed by discontinuation) were described among individuals with a viral load < 50 copies/mL at initiation and ≥ 1 follow-up viral load. Results Among 321 individuals on CAB + RPV LA, 90% of the continuation injections were administered on time (within ± 7 days of the target date). Of the 237 individuals with a viral load < 50 copies/mL at initiation and ≥ 1 follow-up viral load, nearly all were undetectable (95%) or suppressed (99%) at their last viral load measurement, 96% maintained virologic suppression with all measured viral loads < 200 copies/mL, and four confirmed virologic failures were observed. Injection delays were infrequent, and did not affect virologic outcomes over the short term. Conclusion In this large US cohort, most monthly CAB + RPV LA injections were administered on time and high levels of virologic control were achieved. These results suggest that CAB + RPB LA injectable can be administered effectively during routine clinical care.
Duration of SARS-CoV-2 sero-positivity in a large longitudinal sero-surveillance cohort: the COVID-19 Community Research Partnership
Background Estimating population prevalence and incidence of prior SARS-CoV-2 infection is essential to formulate public health recommendations concerning the COVID-19 pandemic. However, interpreting estimates based on sero-surveillance requires an understanding of the duration of elevated antibodies following SARS-CoV-2 infection, especially in the large number of people with pauci-symptomatic or asymptomatic disease. Methods We examined > 30,000 serology assays for SARS-CoV-2 specific IgG and IgM assays acquired longitudinally in 11,468 adults between April and November 2020 in the COVID-19 Community Research Partnership. Results Among participants with serologic evidence for infection but few or no symptoms or clinical disease, roughly 50% sero-reverted in 30 days of their initial positive test. Sero-reversion occurred more quickly for IgM than IgG and for antibodies targeting nucleocapsid protein compared with spike proteins, but was not associated with age, sex, race/ethnicity, or healthcare worker status. Conclusions The short duration of antibody response suggests that the true population prevalence of prior SARS-CoV-2 infection may be significantly higher than presumed based on earlier sero-surveillance studies. The impact of the large number of minimally symptomatic COVID-19 cases with only a brief antibody response on population immunity remains to be determined.
Advanced HIV Infection in Treatment-Naïve Individuals: Effectiveness and Persistence of Recommended 3-Drug Regimens
Abstract Background Approximately 20% of newly diagnosed people with HIV (PWH) in the United States have advanced HIV infection, yet the literature on current antiretroviral therapy (ART) options is limited. The discontinuation/modification and effectiveness of common regimens were compared among ART-naïve people with advanced HIV infection (CD4 cell count <200 cells/μL). Methods ART-naïve adults with advanced HIV infection initiating bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) or a boosted darunavir (bDRV)-, dolutegravir (DTG)-, or elvitegravir/cobicistat (EVG/c)-based 3-drug regimen between January 1, 2018, and July 31, 2019, in the OPERA cohort were included. The association between regimen and discontinuation or viral suppression (<50 or <200 copies/mL) was assessed using Cox proportional hazards models with inverse probability of treatment weights. Results Overall, 961 PWH were included (416 B/F/TAF, 106 bDRV, 271 DTG, 168 EVG/c); 70% achieved a CD4 cell count ≥200 cells/μL over a 16-month median follow-up. All regimens were associated with a statistically higher likelihood of discontinuation than B/F/TAF (bDRV: adjusted hazard ratio [aHR], 2.65; 95% CI, 1.75–4.02; DTG: aHR, 2.42; 95% CI, 1.75–3.35; EVG/c: aHR, 3.52; 95% CI, 2.44–5.07). Compared with B/F/TAF, bDRV initiators were statistically less likely to suppress to <50 copies/mL (aHR, 0.72; 95% CI, 0.52–0.99) and <200 copies/mL (aHR, 0.55; 95% CI, 0.43–0.70); no statistically significant difference was detected with DTG or EVG/c. Conclusions Among people with advanced HIV infection, those initiating B/F/TAF were less likely to discontinue/modify their regimen than those on any other regimen, and more likely to achieve viral suppression compared with those on bDRV but not compared with those on other integrase inhibitors.
Protocol for a two-arm pragmatic stepped-wedge hybrid effectiveness-implementation trial evaluating Engagement and Collaborative Management to Proactively Advance Sepsis Survivorship (ENCOMPASS)
Background Sepsis survivors experience high morbidity and mortality, and healthcare systems lack effective strategies to address patient needs after hospital discharge. The Sepsis Transition and Recovery (STAR) program is a navigator-led, telehealth-based multicomponent strategy to provide proactive care coordination and monitoring of high-risk patients using evidence-driven, post-sepsis care tasks. The purpose of this study is to evaluate the effectiveness of STAR to improve outcomes for sepsis patients and to examine contextual factors that influence STAR implementation. Methods This study uses a hybrid type I effectiveness-implementation design to concurrently test clinical effectiveness and gather implementation data. The effectiveness evaluation is a two-arm, pragmatic, stepped-wedge cluster randomized controlled trial at eight hospitals in North Carolina comparing clinical outcomes between sepsis survivors who receive Usual Care versus care delivered through STAR. Each hospital begins in a Usual Care control phase and transitions to STAR in a randomly assigned sequence (one every 4 months). During months that a hospital is allocated to Usual Care, all eligible patients will receive usual care. Once a hospital transitions to STAR, all eligible patients will receive STAR during their hospitalization and extending through 90 days from discharge. STAR includes centrally located nurse navigators using telephonic counseling and electronic health record-based support to facilitate best-practice post-sepsis care strategies including post-discharge review of medications, evaluation for new impairments or symptoms, monitoring existing comorbidities, and palliative care referral when appropriate. Adults admitted with suspected sepsis, defined by clinical criteria for infection and organ failure, are included. Planned enrollment is 4032 patients during a 36-month period. The primary effectiveness outcome is the composite of all-cause hospital readmission or mortality within 90 days of discharge. A mixed-methods implementation evaluation will be conducted before, during, and after STAR implementation. Discussion This pragmatic evaluation will test the effectiveness of STAR to reduce combined hospital readmissions and mortality, while identifying key implementation factors. Results will provide practical information to advance understanding of how to integrate post-sepsis management across care settings and facilitate implementation, dissemination, and sustained utilization of best-practice post-sepsis management strategies in other heterogeneous healthcare delivery systems. Trial registration NCT04495946 . Submitted July 7, 2020; Posted August 3, 2020.
Evaluation of a health system’s implementation of a monkeypox care model under the RE-AIM framework
Objective: Emerging infectious diseases challenge healthcare systems to implement new models of care. We aim to evaluate the rapid implementation of a new care model for monkeypox in our health system. Design: This is a retrospective case series evaluation under the Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework of implementation of a testing and care model for monkeypox in a large, integrated health system. Methods: Atrium Health implemented education of providers, testing protocols, and management of potential monkeypox cases using electronic health record (EHR) data capabilities, telehealth, and collaboration between multiple disciplines. The first 4 weeks of care model implementation were evaluated under the RE-AIM framework. Results: One hundred fifty-three patients were tested for monkeypox by 117 unique providers at urgent care, emergency departments, and infectious disease clinics in our healthcare system between 18 July 2022 and 14 August 2022. Fifty-eight monkeypox cases were identified, compared with 198 cases in the state during the time period, a disproportionate number compared with the health system service area, and 52 patients were assessed for need for tecovirimat treatment. The number of tests performed and providers sending tests increased during the study period. Conclusion: Implementation of a dedicated care model leveraging EHR data support, telehealth, and cross-disciplinary collaboration led to more effective identification and management of emerging infectious diseases and is important for public health. Plain Language Summary Impact of care model implementation on monkeypox New infectious diseases challenge health systems to implement new care practices. Our health system responded to this challenge by implementing a care model for education, testing, and clinical care of monkeypox patients. We analyzed results from implementing the model. We were able to identify a disproportionate number of monkeypox cases compared with the rest of our state by using our model to educate medical providers, encourage testing, and ensure patients had access to best disease care. Implementation of care models for testing and management of new diseases will improve patient care and public health.
Safety, immunogenicity and efficacy of modified vaccinia Ankara (MVA) against Dryvax ® challenge in vaccinia-naïve and vaccinia-immune individuals
Modified vaccinia Ankara (MVA) was evaluated as an alternative to Dryvax ® in vaccinia-naïve and vaccinia-immune adult volunteers. Subjects received intramuscular MVA or placebo followed by Dryvax ® challenge at 3 months. Two or more doses of MVA prior to Dryvax ® reduced severity of lesion formation, decreased magnitude and duration of viral shedding, and augmented post-Dryvax ® vaccinia-specific CD8+ T cell responses and extracellular enveloped virus protein-specific antibody responses. MVA vaccination is safe and immunogenic and improves the safety and immunogenicity of subsequent Dryvax ® vaccination supporting the potential for using MVA as a vaccine in the general population to improve immunity to orthopoxviruses.
Modified Vaccinia Ankara: Potential as an Alternative Smallpox Vaccine
Despite the declaration of smallpox eradication in 1980, the existence of variola stockpiles and the threat of bioterrorism demand that immunity to smallpox through vaccination be maintained. Although the currently available vaccine was used for the most successful medical intervention ever accomplished, it also is associated with side effects that are difficult to accept in a vaccine for a disease that has not been present for >25 years. Herein, we review alternative approaches to maintaining immunity to smallpox through vaccination with attenuated poxviruses, and we suggest modified vaccinia Ankara (MVA) as a leading candidate for an alternative smallpox vaccine.
Infectious Diseases Society of America Position Statement on Telehealth and Telemedicine as Applied to the Practice of Infectious Diseases
Over the last 2 decades, telemedicine has effectively demonstrated its ability to increase access to care. This access has the ability to deliver quality clinical care and offer potential savings to the healthcare system. With increasing frequency, physicians, clinics, and medical centers are harnessing modern telecommunications technologies to manage a multitude of acute and chronic conditions, as well as incorporating telehealth into teaching and research. The technologies spanning telehealth, telemedicine, and mobile health (mHealth) are rapidly evolving, and the Infectious Diseases Society of America (IDSA) has prepared this updated position statement to educate its membership on the use of telemedicine and telehealth technologies. IDSA supports the appropriate and evidence-based use of telehealth technologies to provide up-to-date, timely, cost-effective subspecialty care to resource-limited populations.