Severe Ebola virus disease with vascular leakage and multiorgan failure: treatment of a patient in intensive care

Unlocking endothelial barrier restoration: FX06 in systemic capillary leak syndrome and beyond

Increased vascular permeability is a prevalent feature in a wide spectrum of clinical conditions, but no effective treatments to restore the endothelial barrier are available. Idiopathic systemic capillary leak syndrome (ISCLS) is a life-threatening Paroxysmal Permeability Disorder characterized by abrupt, massive plasma extravasation. This condition serves as a robust model for investigating therapeutic approaches targeting interendothelial junctions. We conducted a single-center, interventional in vitro study at the Referral Center for ISCLS in Italy, involving four diagnosed ISCLS patients, aiming at investigating the effects of FX06, a Bβ15-42 fibrin-derived peptide binding to VE-Cadherin, on endothelial barrier exposed to intercritical and acute ISCLS sera. The Transwell Permeability Assay was used to assess the permeability of human umbilical vein endothelial cells (HUVECs) exposed to ISCLS sera with or without FX06 (50 µg/ml). Acute ISCLS serum was also tested in a three-dimensional microfluidic device. Nitric oxide (NO), VE-Cadherin localization, and cytoskeletal organization were also assessed. In two and three-dimensional systems, ISCLS sera increased endothelial permeability, with a more pronounced effect for acute sera. Furthermore, acute sera altered VE-Cadherin localization and cytoskeletal organization. NO levels remained unchanged. FX06 restored the endothelial barrier function by influencing cellular localization rather than VE-Cadherin levels. In conclusion, FX06 prevents and reverts the hyperpermeability induced by ISCLS sera. These preliminary yet promising results provide initial evidence of the in vitro efficacy of a drug targeting the underlying pathophysiological mechanisms of ISCLS. Moreover, this approach may hold potential for addressing hyperpermeability in a spectrum of clinical conditions beyond ISCLS.

T cell responses to SARS-CoV-2

This chapter provides a comprehensive analysis of T cell responses in COVID-19, focusing on T cell differentiation, specificity, and functional characteristics during SARS-CoV-2 infection. The differentiation of T cells in COVID-19 is explored, highlighting the key factors that influence T cell fate and effector functions. The immunology of the spike protein, a critical component of SARS-CoV-2, is discussed in detail, emphasizing its role in driving T-cell responses. The cellular immune responses against SARS-CoV-2 during acute infection are examined, including the specificity, phenotype, and functional attributes of SARS-CoV-2-specific T-cell responses. Furthermore, the chapter explores T-cell cross-recognition against other human coronaviruses (HCoVs) and the mechanisms of immune regulation mediated by spike proteins. This includes the induction of regulation through the innate immune system, the activation of self-spike protein-cross-reactive regulatory T cells, and the impact of self-tolerance on the regulation of spike proteins. The chapter investigates T cell responses to self-spike proteins and their implications in disease. The role of spike proteins as immunological targets in the context of COVID-19 is examined, shedding light on potential therapeutic interventions and clinical trials in autoimmune diseases. In conclusion, this chapter provides a comprehensive understanding of T cell responses in COVID-19, highlighting their differentiation, immune regulation, and clinical implications. This knowledge contributes to the development of targeted immunotherapies, vaccine strategies, and diagnostic approaches for COVID-19 and other related diseases.

FX06 to rescue SARS-CoV-2-induced acute respiratory distress syndrome: a randomized clinical trial

BACKGROUND

Vascular leakage is a major feature of acute respiratory distress syndrome (ARDS). We aimed to evaluate the efficacy of FX06, a drug under development that stabilizes interendothelial cell junctions, at reducing vascular leakage during SARS-CoV-2-induced ARDS.

METHODS

This multicenter, double-blinded, randomized trial included adults with COVID-19-associated ARDS who had received invasive mechanical ventilation for < 5 days and were randomized to receive either intravenous FX06 (400 mg/d, for 5 days) or its vehicle as placebo. The primary endpoint was the lowering-from day 1 to day 7-of the transpulmonary thermodilution-derived extravascular lung-water index (EVLWi).

RESULTS

Twenty-five patients were randomized to receive FX06 and 24 the placebo. Although EVLWi was elevated at baseline (median [IQR] 15.6 mL/kg [13.5; 18.5]), its declines from day 1 to day 7 were comparable for FX06 recipients and controls (respectively, - 1.9 [- 3.3; - 0.5] vs. - 0.8 [- 5.5; - 1.1] mL/kg; estimated effect - 0.8 [- 3.1; + 2.4], p = 0.51). Cardiac indexes, pulmonary vascular permeability indexes, and fluid balances were also comparable, as were PaO2/FiO2 ratios and durations of mechanical ventilation. Adverse event rates were similar for the 2 groups, although more FX06 recipients developed ventilator-associated pneumonia (16/25 (64%) vs. 6/24 (24%), p = 0.009).

CONCLUSIONS

In this unique-dosing-regimen study, FX06 did not lower SARS-CoV-2-induced pulmonary vascular leakage. Future investigations will need to evaluate its efficacy at earlier times during the disease or using other regimens. Trial registration NCT04618042. Registered 5 November 2020.

A narrative review of high-level isolation unit operational and infrastructure features

High-level isolation units (HLIUs) are specially designed facilities for care and management of patients with suspected or confirmed high-consequence infectious diseases (HCIDs), equipped with unique infrastructure and operational features. While individual HLIUs have published on their experiences caring for patients with HCIDs and two previous HLIU consensus efforts have outlined key components of HLIUs, we aimed to summarise the existing literature that describes best practices, challenges and core features of these specialised facilities. A narrative review of the literature was conducted using keywords associated with HLIUs and HCIDs. A total of 100 articles were used throughout the manuscript from the literature search or from alternate methods like reference checks or snowballing. Articles were sorted into categories (eg, physical infrastructure, laboratory, internal transport); for each category, a synthesis of the relevant literature was conducted to describe best practices, experiences and operational features. The review and summary of HLIU experiences, best practices, challenges and components can serve as a resource for units continuing to improve readiness, or for hospitals in early stages of developing their HLIU teams and planning or constructing their units. The COVID-19 pandemic, a global outbreak of mpox, sporadic cases of viral haemorrhagic fevers in Europe and the USA, and recent outbreaks of Lassa fever, Sudan Ebolavirus, and Marburg emphasise the need for an extensive summary of HLIU practices to inform readiness and response.

Ebola virus disease: A narrative review

Ebola virus disease (EVD), which is also referred to as Ebola hemorrhagic fever, is a highly contagious and frequently lethal sickness caused by the Ebola virus. In 1976, the disease emerged in two simultaneous outbreaks in Sudan and the Democratic Republic of Congo. Subsequently, it has caused intermittent outbreaks in several African nations. The virus is primarily spread via direct contact with the bodily fluids of an infected individual or animal. EVD is distinguished by symptoms such as fever, fatigue, muscle pain, headache, and hemorrhage. The outbreak of EVD in West Africa in 2014-2016 emphasized the need for effective control and prevention measures. Despite advancements and the identification of new treatments for EVD, the primary approach to treatment continues to be centered around providing supportive care. Early detection and supportive care can enhance the likelihood of survival. This includes intravenous fluids, electrolyte replacement, and treatment of secondary infections. Experimental therapies, for instance, monoclonal antibodies and antiviral drugs, have shown promising results in animal studies and some clinical trials. Some African countries have implemented the use of vaccines developed for EVD, but their effectiveness and long-term safety are still being studied. This article provides an overview of the history, transmission, symptoms, diagnosis, treatment, epidemiology, and Ebola coinfection, as well as highlights the ongoing research efforts to develop effective treatments and vaccines to combat this deadly virus.

Microvascular Leakage as Therapeutic Target for Ischemia and Reperfusion Injury

Reperfusion injury is a very common complication of various indicated therapies such as the re-opening of vessels in the myocardium or brain as well as reflow in hemodynamic shutdown (cardiac arrest, severe trauma, aortic cross-clamping). The treatment and prevention of reperfusion injury has therefore been a topic of immense interest in terms of mechanistic understanding, the exploration of interventions in animal models and in the clinical setting in major prospective studies. While a wealth of encouraging results has been obtained in the lab, the translation into clinical success has met with mixed outcomes at best. Considering the still very high medical need, progress continues to be urgently needed. Multi-target approaches rationally linking interference with pathophysiological pathways as well as a renewed focus on aspects of microvascular dysfunction, especially on the role of microvascular leakage, are likely to provide new insights.

Ebola virus-like particles reprogram cellular metabolism

Ebola virus can trigger a release of pro-inflammatory cytokines with subsequent vascular leakage and impairment of clotting finally leading to multiorgan failure and shock after entering and infecting patients. Ebola virus is known to directly target endothelial cells and macrophages, even without infecting them, through direct interactions with viral proteins. These interactions affect cellular mechanics and immune processes, which are tightly linked to other key cellular functions such as metabolism. However, research regarding metabolic activity of these cells upon viral exposure remains limited, hampering our understanding of its pathophysiology and progression. Therefore, in the present study, an untargeted cellular metabolomic approach was performed to investigate the metabolic alterations of primary human endothelial cells and M1 and M2 macrophages upon exposure to Ebola virus-like particles (VLP). The results show that Ebola VLP led to metabolic changes among endothelial, M1, and M2 cells. Differential metabolite abundance and perturbed signaling pathway analysis further identified specific metabolic features, mainly in fatty acid-, steroid-, and amino acid-related metabolism pathways for all the three cell types, in a host cell specific manner. Taken together, this work characterized for the first time the metabolic alternations of endothelial cells and two primary human macrophage subtypes after Ebola VLP exposure, and identified the potential metabolites and pathways differentially affected, highlighting the important role of those host cells in disease development and progression. KEY MESSAGES: • Ebola VLP can lead to metabolic alternations in endothelial cells and M1 and M2 macrophages. • Differential abundance of metabolites, mainly including fatty acids and sterol lipids, was observed after Ebola VLP exposure. • Multiple fatty acid-, steroid-, and amino acid-related metabolism pathways were observed perturbed.

Burgeoning therapeutic strategies to curb the contemporary surging viral infections

Significant efforts and initiatives were already made in the health care systems, however in the last few years; our world is facing emergences of viral infections which potentially leading to considerable challenges in terms of higher morbidity, mortality, increased and considerable financial loads on the affected populations. Over ten major epidemics or pandemics have been recorded in the twenty-first century, the ongoing coronavirus pandemic being one of them. Viruses being distinct obligate pathogens largely dependent on living beings are considered as one of the prominent causes of death globally. Although effective vaccines and antivirals have led to the eradication of imperative viral pathogens, the emergences of new viral infections as well as novel drug-resistant strains have necessitated the implementation of ingenious and efficient therapeutic approaches to treat viral outbreaks in the future. Nature being a constant source of tremendous therapeutical resources has inspired us to develop multi-target antiviral drugs, overcoming the challenges and limitations faced by pharmaceutical industry. Recent breakthroughs in the understanding of the cellular and molecular mechanisms of viral reproduction have laid the groundwork for potential treatment approaches including antiviral gene therapy relying on the application of precisely engineered nucleic acids for disabling pathogen replication. The development of RNA interference and advancements in genome manipulating tools have proven to be especially significant in this regard. In this review, we discussed mode of actions and pathophysiological events associated with the viral infections; followed by distributions, and advancement made towards the detection strategies for timely diagnosis. In the later section, current approaches to cope up the viral pathogens and their key limitations have also been elaborated. Lastly, we also explored some novel and potential targets to treat such infections, where attentions were made on next generation gene editing technologies.

Differential symptomology of possible and confirmed Ebola virus disease infection in the Democratic Republic of the Congo: a retrospective cohort study

BACKGROUND

In its earliest phases, Ebola virus disease's rapid-onset, high fever, and gastrointestinal symptoms are largely indistinguishable from other infectious illnesses. We aimed to characterise the clinical indicators associated with Ebola virus disease to improve outbreak response.

METHODS

In this retrospective analysis, we assessed routinely collected data from individuals with possible Ebola virus disease attending 30 Ebola health facilities in two provinces of the Democratic Republic of the Congo between Aug 1, 2018, and Aug 28, 2019. We used logistic regression analysis to model the probability of Ebola infection across 34 clinical variables and four types of possible Ebola virus disease exposures: contact with an individual known to have Ebola virus disease, attendance at any funeral, health facility consultation, or consultation with an informal health practitioner.

FINDINGS

Data for 24 666 individuals were included. If a patient presented to care in the early symptomatic phase (ie, days 0-2), Ebola virus disease positivity was most associated with previous exposure to an individual with Ebola virus disease (odds ratio [OR] 11·9, 95% CI 9·1-15·8), funeral attendance (2·1, 1·6-2·7), or health facility consultations (2·1, 1·6-2·8), rather than clinical parameters. If presentation occurred on day 3 or later (after symptom onset), bleeding at an injection site (OR 33·9, 95% CI 12·7-101·3), bleeding gums (7·5, 3·7-15·4), conjunctivitis (2·4, 1·7-3·4), asthenia (1·9, 1·5-2·3), sore throat (1·8, 1·3-2·4), dysphagia (1·8, 1·4-2·3), and diarrhoea (1·6, 1·3-1·9) were additional strong predictors of Ebola virus disease. Some Ebola virus disease-specific signs were less prevalent among vaccinated individuals who were positive for Ebola virus disease when compared with the unvaccinated, such as dysphagia (-47%, p=0·0024), haematemesis (-90%, p=0·0131), and bleeding gums (-100%, p=0·0035).

INTERPRETATION

Establishing the exact time an individual first had symptoms is essential to assessing their infection risk. An individual's exposure history remains of paramount importance, especially in the early phase. Ebola virus disease vaccination reduces symptom severity and should also be considered when assessing the likelihood of infection. These findings about symptomatology should be translated into practice during triage and should inform testing and quarantine procedures.

FUNDING

Médecins Sans Frontières and its research affiliate Epicentre.

The Emergence of Travel-related Infections in Critical Care Units

Several tropical or geographically confined infectious diseases may lead to organ failure requiring management in an intensive care unit (ICU), both in endemic low- and middle-income countries where ICU facilities are increasingly being developed and in (nonendemic) high-income countries through an increase in international travel and migration. The ICU physician must know which of these diseases may be encountered and how to recognize, differentiate, and treat them. The four historically most prevalent "tropical" diseases (malaria, enteric fever, dengue, and rickettsiosis) can present with single or multiple organ failure in a very similar manner, which makes differentiation based solely on clinical signs very difficult. Specific but frequently subtle symptoms should be considered and related to the travel history of the patient, the geographic distribution of these diseases, and the incubation period. In the future, ICU physicians may also be more frequently confronted with rare but frequently lethal diseases, such as Ebola and other viral hemorrhagic fevers, leptospirosis, and yellow fever. No one could have foreseen the worldwide 2019-up to now coronavirus disease 2019 (COVID-19) crisis caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which was initially spread by travel too. In addition, the actual pandemic due to SARS-CoV-2 reminds us of the actual and potential threat of (re)-emerging pathogens. If left untreated or when treated with a delay, many travel-related diseases remain an important cause of morbidity and even mortality, even when high-quality critical care is provided. Awareness and a high index of suspicion of these diseases is a key skill for the ICU physicians of today and tomorrow to develop.

Comparative Animal Models of Human Viral Infections

Comparative animal modeling has long served as a cornerstone for understanding the biological effects of infection by many DNA and RNA viruses [...].

Development of an imaging system for visualization of Ebola virus glycoprotein throughout the viral lifecycle

Ebola virus (EBOV) causes severe EBOV disease (EVD) in humans and non-human primates. Currently, limited countermeasures are available, and the virus must be studied in biosafety level-4 (BSL-4) laboratories. EBOV glycoprotein (GP) is a single transmembrane protein responsible for entry into host cells and is the target of multiple approved drugs. However, the molecular mechanisms underlying the intracellular dynamics of GP during EBOV lifecycle are poorly understood. In this study, we developed a novel GP monitoring system using transcription- and replication-competent virus-like particles (trVLPs) that enables the modeling of the EBOV lifecycle under BSL-2 conditions. We constructed plasmids to generate trVLPs containing the coding sequence of EBOV GP, in which the mucin-like domain (MLD) was replaced with fluorescent proteins. The generated trVLP efficiently replicated over multiple generations was similar to the wild type trVLP. Furthermore, we confirmed that the novel trVLP system enabled real-time visualization of GP throughout the trVLP replication cycle and exhibited intracellular localization similar to that of wild type GP. In summary, this novel monitoring system for GP will enable the characterization of the molecular mechanism of the EBOV lifecycle and can be applied for the development of therapeutics against EVD.

Current View on the Molecular Mechanisms Underlying Fibrin(ogen)-Dependent Inflammation

Numerous studies have revealed the involvement of fibrinogen in the inflammatory response. To explain the molecular mechanisms underlying fibrinogen-dependent inflammation, two bridging mechanisms have been proposed in which fibrin(ogen) bridges leukocytes to endothelial cells. The first mechanism suggests that bridging occurs via the interaction of fibrinogen with the leukocyte receptor Mac-1 and the endothelial receptor ICAM-1 (intercellular adhesion molecule-1), which promotes leukocyte transmigration and enhances inflammation. The second mechanism includes bridging of leukocytes to the endothelium by fibrin degradation product E1 fragment through its interaction with leukocyte receptor CD11c and endothelial VE-cadherin to promote leukocyte transmigration. The role of E1 in promoting inflammation is inhibited by the fibrin-derived β15-42 fragment, and this has been suggested to result from its ability to compete for the E1-VE-cadherin interaction and to trigger signaling pathways through the src kinase Fyn. Our recent study revealed that the β15-42 fragment is ineffective in inhibiting the E1- or fibrin-VE-cadherin interaction, leaving the proposed signaling mechanism as the only viable explanation for the inhibitory function of β15-42. We have discovered that fibrin interacts with the very-low-density lipoprotein (VLDL) receptor, and this interaction triggers a signaling pathway that promotes leukocyte transmigration through inhibition of the src kinase Fyn. This pathway is inhibited by another pathway induced by the interaction of β15-42 with a putative endothelial receptor. In this review, we briefly describe the previously proposed molecular mechanisms underlying fibrin-dependent inflammation and their advantages/disadvantages and summarize our recent studies of the novel VLDL receptor-dependent pathway of leukocyte transmigration which plays an important role in fibrin-dependent inflammation.

Activation of TLR4 by viral glycoproteins: A double-edged sword?

Recognition of viral infection by pattern recognition receptors is paramount for a successful immune response to viral infection. However, an unbalanced proinflammatory response can be detrimental to the host. Recently, multiple studies have identified that the SARS-CoV-2 spike protein activates Toll-like receptor 4 (TLR4), resulting in the induction of proinflammatory cytokine expression. Activation of TLR4 by viral glycoproteins has also been observed in the context of other viral infection models, including respiratory syncytial virus (RSV), dengue virus (DENV) and Ebola virus (EBOV). However, the mechanisms involved in virus-TLR4 interactions have remained unclear. Here, we review viral glycoproteins that act as pathogen-associated molecular patterns to induce an immune response via TLR4. We explore the current understanding of the mechanisms underlying how viral glycoproteins are recognized by TLR4 and discuss the contribution of TLR4 activation to viral pathogenesis. We identify contentious findings and research gaps that highlight the importance of understanding viral glycoprotein-mediated TLR4 activation for potential therapeutic approaches.

Potential of FX06 to prevent disease progression in hospitalized non-intubated COVID-19 patients - the randomized, EU-wide, placebo-controlled, phase II study design of IXION

BACKGROUND

More than 2.7 million hospitalizations of COVID-19-infected patients have occurred in Europe alone since the outbreak of the coronavirus in 2020. Interventions against SARS-CoV-2 are still in high need to prevent admissions to ICUs worldwide. FX06, a naturally occurring peptide in humans and other mammals, has the potential to reduce capillary leak by improving endothelial dysfunction and thus preventing the deterioration of patients. With IXION, we want to investigate the potential of FX06 to prevent disease progression in hospitalized, non-intubated COVID-19 patients.

METHODS

IXION is an EU-wide, multicentre, placebo-controlled, double-blinded, parallel, randomized (2:1) phase II clinical study. Patient recruitment will start in September 2022 (to Q2/2023) in Germany, Italy, Lithuania, Spain, Romania, Portugal, and France. A total of 306 hospitalized patients (≥ 18 years and < 75 years) with a positive SARS-CoV-2 PCR test and a COVID-19 severity of 4-6 according to the WHO scale will be enrolled. After randomization to FX06 or placebo, patients will be assessed until day 28 (and followed up until day 60). FX06 (2 × 200 mg per day) or placebo will be administered intravenously for 5 consecutive days. The primary endpoint is to demonstrate a difference in the proportion of patients with progressed/worsened disease state in patients receiving FX06 compared to patients receiving placebo. Secondary endpoints are lung function, oxygen saturation and breathing rate, systemic inflammation, survival, capillary refill time, duration of hospital stay, and drug accountability.

DISCUSSION

With IXION, the multidisciplinary consortium aims to deliver a new therapy in addition to standard care against SARS-CoV-2 for the clinical management of COVID-19 during mild and moderate stages. Potential limitations might refer to a lack of recruiting and drop-out due to various possible protocol violations. While we controlled for drop-outs in the same size estimation, recruitment problems may be subject to external problems difficult to control for.

TRIAL REGISTRATION

EudraCT 2021-005059-35 . Registered on 12 December 2021. Study Code TMP-2204-2021-47.

Thromboprophylaxis with argatroban in critically ill patients with sepsis: a review

During sepsis, an initial prothrombotic shift takes place, in which coagulatory acute-phase proteins are increased, while anticoagulatory factors and platelet count decrease. Further on, the fibrinolytic system becomes impaired, which contributes to disease severity. At a later stage in sepsis, coagulation factors may become depleted, and sepsis patients may shift into a hypo-coagulable state with an increased bleeding risk. During the pro-coagulatory shift, critically ill patients have an increased thrombosis risk that ranges from developing micro-thromboses that impair organ function to life-threatening thromboembolic events. Here, thrombin plays a key role in coagulation as well as in inflammation. For thromboprophylaxis, low molecular weight heparins (LMWH) and unfractionated heparins (UFHs) are recommended. Nevertheless, there are conditions such as heparin resistance or heparin-induced thrombocytopenia (HIT), wherein heparin becomes ineffective or even puts the patient at an increased prothrombotic risk. In these cases, argatroban, a direct thrombin inhibitor (DTI), might be a potential alternative anticoagulatory strategy. Yet, caution is advised with regard to dosing of argatroban especially in sepsis. Therefore, the starting dose of argatroban is recommended to be low and should be titrated to the targeted anticoagulation level and be closely monitored in the further course of treatment. The authors of this review recommend using DTIs such as argatroban as an alternative anticoagulant in critically ill patients suffering from sepsis or COVID-19 with suspected or confirmed HIT, HIT-like conditions, impaired fibrinolysis, in patients on extracorporeal circuits and patients with heparin resistance, when closely monitored.

Automated Laser-Transfer Synthesis of High-Density Microarrays for Infectious Disease Screening

Laser-induced forward transfer (LIFT) is a rapid laser-patterning technique for high-throughput combinatorial synthesis directly on glass slides. A lack of automation and precision limits LIFT applications to simple proof-of-concept syntheses of fewer than 100 compounds. Here, an automated synthesis instrument is reported that combines laser transfer and robotics for parallel synthesis in a microarray format with up to 10 000 individual reactions cm^{- 2} . An optimized pipeline for amide bond formation is the basis for preparing complex peptide microarrays with thousands of different sequences in high yield with high reproducibility. The resulting peptide arrays are of higher quality than commercial peptide arrays. More than 4800 15-residue peptides resembling the entire Ebola virus proteome on a microarray are synthesized to study the antibody response of an Ebola virus infection survivor. Known and unknown epitopes that serve now as a basis for Ebola diagnostic development are identified. The versatility and precision of the synthesizer is demonstrated by in situ synthesis of fluorescent molecules via Schiff base reaction and multi-step patterning of precisely definable amounts of fluorophores. This automated laser transfer synthesis approach opens new avenues for high-throughput chemical synthesis and biological screening.

PET imaging of TSPO expression in immune cells can assess organ-level pathophysiology in high-consequence viral infections

Ebola virus (EBOV) disease is characterized by lymphopenia, breach in vascular integrity, cytokine storm, and multiorgan failure. The pathophysiology of organ involvement, however, is incompletely understood. Using [18F]-DPA-714 positron emission tomography (PET) imaging targeting the translocator protein (TSPO), an immune cell marker, we sought to characterize the progression of EBOV-associated organ-level pathophysiology in the EBOV Rhesus macaque model. Dynamic [18F]-DPA-714 PET/computed tomography imaging was performed longitudinally at baseline and at multiple time points after EBOV inoculation, and distribution volumes (Vt) were calculated as a measure of peripheral TSPO binding. Using a mixed-effect linear regression model, spleen and lung Vt decreased, while the bone marrow Vt increased over time after infection. No clear trend was found for liver Vt. Multiple plasma cytokines correlated negatively with lung/spleen Vt and positively with bone marrow Vt. Multiplex immunofluorescence staining in spleen and lung sections confirmed organ-level lymphoid and monocytic loss/apoptosis, thus validating the imaging results. Our findings are consistent with EBOV-induced progressive monocytic and lymphocytic depletion in the spleen, rather than immune activation, as well as depletion of alveolar macrophages in the lungs, with inefficient reactive neutrophilic activation. Increased bone marrow Vt, on the other hand, suggests hematopoietic activation in response to systemic immune cell depletion and leukocytosis and could have prognostic relevance. In vivo PET imaging provided better understanding of organ-level pathophysiology during EBOV infection. A similar approach can be used to delineate the pathophysiology of other systemic infections and to evaluate the effectiveness of newly developed treatment and vaccine strategies.

Preparing for patients with high-consequence infectious diseases: Example of a high-level isolation unit

Introduction

Patients with high-consequence infectious diseases (HCID) are rare in Western Europe. However, high-level isolation units (HLIU) must always be prepared for patient admission. Case fatality rates of HCID can be reduced by providing optimal intensive care management. We here describe a single centre’s preparation, its embedding in the national context and the challenges we faced during the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) pandemic.

Methods

Ten team leaders organize monthly whole day trainings for a team of doctors and nurses from the HLIU focusing on intensive care medicine. Impact and relevance of training are assessed by a questionnaire and a perception survey, respectively. Furthermore, yearly exercises with several partner institutions are performed to cover different real-life scenarios. Exercises are evaluated by internal and external observers. Both training sessions and exercises are accompanied by intense feedback.

Results

From May 2017 monthly training sessions were held with a two-month and a seven-month break due to the first and second wave of the SARS-CoV-2 pandemic, respectively. Agreement with the statements of the questionnaire was higher after training compared to before training indicating a positive effect of training sessions on competence. Participants rated joint trainings for nurses and doctors at regular intervals as important. Numerous issues with potential for improvement were identified during post processing of exercises. Action plans for their improvement were drafted and as of now mostly implemented. The network of the permanent working group of competence and treatment centres for HCID (Ständiger Arbeitskreis der Kompetenz- und Behandlungszentren für Krankheiten durch hochpathogene Erreger (STAKOB)) at the Robert Koch-Institute (RKI) was strengthened throughout the SARS-CoV-2 pandemic.

Discussion

Adequate preparation for the admission of patients with HCID is challenging. We show that joint regular trainings of doctors and nurses are appreciated and that training sessions may improve perceived skills. We also show that real-life scenario exercises may reveal additional deficits, which cannot be easily disclosed in training sessions. Although the SARS-CoV-2 pandemic interfered with our activities the enhanced cooperation among German HLIU during the pandemic ensured constant readiness for the admission of HCID patients to our or to collaborating HLIU. This is a single centre’s experience, which may not be generalized to other centres. However, we believe that our work may address aspects that should be considered when preparing a unit for the admission of patients with HCID. These may then be adapted to the local situations.

Endothelial dysfunction contributes to severe COVID-19 in combination with dysregulated lymphocyte responses and cytokine networks

The systemic processes involved in the manifestation of life-threatening COVID-19 and in disease recovery are still incompletely understood, despite investigations focusing on the dysregulation of immune responses after SARS-CoV-2 infection. To define hallmarks of severe COVID-19 in acute disease (n = 58) and in disease recovery in convalescent patients (n = 28) from Hannover Medical School, we used flow cytometry and proteomics data with unsupervised clustering analyses. In our observational study, we combined analyses of immune cells and cytokine/chemokine networks with endothelial activation and injury. ICU patients displayed an altered immune signature with prolonged lymphopenia but the expansion of granulocytes and plasmablasts along with activated and terminally differentiated T and NK cells and high levels of SARS-CoV-2-specific antibodies. The core signature of seven plasma proteins revealed a highly inflammatory microenvironment in addition to endothelial injury in severe COVID-19. Changes within this signature were associated with either disease progression or recovery. In summary, our data suggest that besides a strong inflammatory response, severe COVID-19 is driven by endothelial activation and barrier disruption, whereby recovery depends on the regeneration of the endothelial integrity.

Powered air-purifying respirators used during the SARS-CoV-2 pandemic significantly reduce speech perception

BACKGROUND

Due to the coronavirus disease 2019 (COVID-19) pandemic, interventions in the upper airways are considered high-risk procedures for otolaryngologists and their colleagues. The purpose of this study was to evaluate limitations in hearing and communication when using a powered air-purifying respirator (PAPR) system to protect against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) transmission and to assess the benefit of a headset.

METHODS

Acoustic properties of the PAPR system were measured using a head and torso simulator. Audiological tests (tone audiometry, Freiburg speech test, Oldenburg sentence test (OLSA)) were performed in normal-hearing subjects (n = 10) to assess hearing with PAPR. The audiological test setup also included simulation of conditions in which the target speaker used either a PAPR, a filtering face piece (FFP) 3 respirator, or a surgical face mask.

RESULTS

Audiological measurements revealed that sound insulation by the PAPR headtop and noise, generated by the blower-assisted respiratory protection system, resulted in significantly deteriorated hearing thresholds (4.0 ± 7.2 dB hearing level (HL) vs. 49.2 ± 11.0 dB HL, p < 0.001) and speech recognition scores in quiet (100.0 ± 0.0% vs. 2.5 ± 4.2%, p < 0.001; OLSA: 20.8 ± 1.8 dB vs. 61.0 ± 3.3 dB SPL, p < 0.001) when compared to hearing without PAPR. Hearing with PAPR was significantly improved when the subjects were equipped with an in-ear headset (p < 0.001). Sound attenuation by FFP3 respirators and surgical face masks had no clinically relevant impact on speech perception.

CONCLUSIONS

The PAPR system evaluated here can be considered for high-risk procedures in SARS-CoV-2-positive patients, provided that hearing and communication of the surgical team are optimized by the additional use of a headset.

COVID-19: Sleep, Circadian Rhythms and Immunity - Repurposing Drugs and Chronotherapeutics for SARS-CoV-2

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has affected nearly 28 million people in the United States and has caused more than five hundred thousand deaths as of February 21, 2021. As the novel coronavirus continues to take its toll in the United States and all across the globe, particularly among the elderly (>65 years), clinicians and translational researchers are taking a closer look at the nexus of sleep, circadian rhythms and immunity that may contribute toward a more severe coronavirus disease-19 (COVID-19). SARS-CoV-2-induced multi-organ failure affects both central and peripheral organs, causing increased mortality in the elderly. However, whether differences in sleep, circadian rhythms, and immunity between older and younger individuals contribute to the age-related differences in systemic dysregulation of target organs observed in SARS-CoV-2 infection remain largely unknown. Current literature demonstrates the emerging role of sleep, circadian rhythms, and immunity in the development of chronic pulmonary diseases and respiratory infections in human and mouse models. The exact mechanism underlying acute respiratory distress syndrome (ARDS) and other cardiopulmonary complications in elderly patients in combination with associated comorbidities remain unclear. Nevertheless, understanding the critical role of sleep, circadian clock dysfunction in target organs, and immune status of patients with SARS-CoV-2 may provide novel insights into possible therapies. Chronotherapy is an emerging concept that is gaining attention in sleep medicine. Accumulating evidence suggests that nearly half of all physiological functions follow a strict daily rhythm. However, healthcare professionals rarely take implementing timed-administration of drugs into consideration. In this review, we summarize recent findings directly relating to the contributing roles of sleep, circadian rhythms and immune response in modulating infectious disease processes, and integrate chronotherapy in the discussion of the potential drugs that can be repurposed to improve the treatment and management of COVID-19.

Ten years of weekly epidemiological teleconference (EpiLag) - an effective and time-efficient tool for infectious disease event information, Germany, 2009-2018

In 2009, the Robert Koch Institute (RKI) and the 16 German federal state public health authorities (PHAs) established a weekly epidemiological teleconference (EpiLag) to discuss infectious disease (ID) events and foster horizontal and vertical information exchange. We present the procedure, discussed ID topics and evaluation results of EpiLag after 10 years. We analysed attendance, duration of EpiLag and the frequency of reported events. Participants (RKI and state PHA) were surveyed regarding their satisfaction with logistics, contents and usefulness of EpiLag (Likert scales). Between 2009 and 2018, RKI hosted 484 EpiLag conferences with a mean duration of 25 min (range: 4–60) and high participation (range: 9–16; mean: 15 PHAs). Overall, 2975 ID events (39% international, 9% national and 52% subnational) were presented (mean: 6.1 per EpiLag), most frequently on measles (18%), salmonellosis (8%) and influenza (5%). All responding participants (14/16 PHAs and 9/9 at RKI) were satisfied with the EpiLag's organization and minutes and deemed EpiLag useful for an overview and information distribution on ID events relevant to Germany. EpiLag is time efficient, easily applicable and useful for a low-threshold event communication. It supports PHAs in crises and strengthens the network of surveillance stakeholders. We recommend its implementation to other countries or sectors.

Antimicrobial peptides and other peptide-like therapeutics as promising candidates to combat SARS-CoV-2

Introduction: There are currently no specific drugs and universal vaccines for Coronavirus disease 2019 (COVID-19), hence urgent effective measures are needed to discover and develop therapeutic agents. Applying peptide therapeutics and their related compounds is a promising strategy to achieve this goal. This review is written based on the literature search using several databases, previous studies, scientific reports, our current knowledge about the antimicrobial peptides (AMPs), and our personal analyses on the potential of the antiviral peptides for the treatment of COVID-19.

Areas covered: In this review, we begin with a brief description of SARS-CoV2 followed by a comprehensive description of antiviral peptides (AVPs) including natural and synthetic AMPs or AVPs and peptidomimetics. Subsequently, the structural features, mechanisms of action, limitations, and therapeutic applications of these peptides are explained.

Expert opinion: Regarding the lack and the limitations of drugs against COVID-19, AMPs, AVPs, and other peptide-like compounds such as peptidomimetics have captured the attention of researchers due to their potential antiviral activities. Some of these compounds comprise unique properties and have demonstrated the potential to fight SARS-CoV2, particularly melittin, lactoferrin, enfuvirtide, and rupintrivir that have the potential to enter animal and clinical trials for the treatment of COVID-19.

Convalescent COVID-19 patients are susceptible to endothelial dysfunction due to persistent immune activation

Numerous reports of vascular events after an initial recovery from COVID-19 form our impetus to investigate the impact of COVID-19 on vascular health of recovered patients. We found elevated levels of circulating endothelial cells (CECs), a biomarker of vascular injury, in COVID-19 convalescents compared to healthy controls. In particular, those with pre-existing conditions (e.g., hypertension, diabetes) had more pronounced endothelial activation hallmarks than non-COVID-19 patients with matched cardiovascular risk. Several proinflammatory and activated T lymphocyte-associated cytokines sustained from acute infection to recovery phase, which correlated positively with CEC measures, implicating cytokine-driven endothelial dysfunction. Notably, we found higher frequency of effector T cells in our COVID-19 convalescents compared to healthy controls. The activation markers detected on CECs mapped to counter receptors found primarily on cytotoxic CD8⁺ T cells, raising the possibility of cytotoxic effector cells targeting activated endothelial cells. Clinical trials in preventive therapy for post-COVID-19 vascular complications may be needed.

Immunotherapeutics for Ebola Virus Disease: Hope on the Horizon

Ebola virus disease (EVD) remains among the biggest public health threats in Africa, even though recently a vaccine was approved for human use. However, in outbreak situations treatment strategies are needed in combination with vaccination campaigns to impact and stop the spread of the disease. Here, we discuss the development of the immunotherapeutics against EDV both targeting the virus itself and bolstering the immunological environment of the host at both the pre-clinical and clinical level. The early development of antibody therapy in preclinical settings and the early pitfalls in the implementation of this therapeutic strategy are discussed. We also consider the advancement of the production, modulation, and specificity of the antibody treatment that garnered increased success in preclinical studies to the point that it was warranted to test them in a clinical setting. Initial clinical trials in an outbreak scenario proved difficult to definitively confirm the efficacy of the implemented treatment. Upon further modification and with the experiences from the challenging outbreak conditions in mind, the PALM clinical trial demonstrated efficacy of an antibody cocktail which recently received approval for human use.

The sphingosine kinase 1 activator, K6PC-5, attenuates Ebola virus infection

Ebola virus (EBOV) is responsible for outbreaks with case fatality rates of up to 90% and for an epidemic in West Africa with more than ten thousand deaths. EBOV glycoprotein (EBOV-GP) is the only viral surface protein and is responsible for viral entry into cells. Here, by employing pseudotyped EBOV-GP viral particles, we uncover a critical role for sphingolipids in inhibiting viral entry. Sphingosine kinase 1 (SphK1) catalyzes the phosphorylation of sphingosine to sphingosine 1-phosphate (S1P). The administration of the SphK1 activator, K6PC-5, or S1P, or the overexpression of SphK1 consistently exhibited striking inhibitory effects in EBOV-GP-driven entry in diverse cell lines. Finally, K6PC-5 markedly reduced the EBOV titer in infected cells and the de novo production of viral proteins. These data present K6PC-5 as an efficient tool to inhibit EBOV infection in endothelial cells and suggest further studies to evaluate its systemic effects.

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K6PC-5, a sphingosine kinase 1 activator, inhibits Ebola virus infection

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Sphingosine 1-phosphate, the product of SphK1, attenuates the viral entry

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Inhibiton/activation of S1P receptors has no influence on Ebola virus entry

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These data support the endogen effect of S1P in Ebola virus infection

Remote-Controlled and Pulse Pressure-Guided Fluid Treatment for Adult Patients with Viral Hemorrhagic Fevers

Circulatory shock, caused by severe intravascular volume depletion resulting from gastrointestinal losses and profound capillary leak, is a common clinical feature of viral hemorrhagic fevers, including Ebola virus disease, Marburg hemorrhagic fever, and Lassa fever. These conditions are associated with high case fatality rates, and they carry a significant risk of infection for treating personnel. Optimized fluid therapy is the cornerstone of management of these diseases, but there are few data on the extent of fluid losses and the severity of the capillary leak in patients with VHFs, and no specific guidelines for fluid resuscitation and hemodynamic monitoring exist. We propose an innovative approach for monitoring VHF patients, in particular suited for low-resource settings, facilitating optimizing fluid therapy through remote-controlled and pulse pressure–guided fluid resuscitation. This strategy would increase the capacity for adequate supportive care, while decreasing the risk for virus transmission to health personnel.

Viral Pandemics of the Last Four Decades: Pathophysiology, Health Impacts and Perspectives

The twenty-first century has witnessed some of the deadliest viral pandemics with far-reaching consequences. These include the Human Immunodeficiency Virus (HIV) (1981), Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) (2002), Influenza A virus subtype H1N1 (A/H1N1) (2009), Middle East Respiratory Syndrome Coronavirus (MERS-CoV) (2012) and Ebola virus (2013) and the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) (2019-present). Age- and gender-based characterizations suggest that SARS-CoV-2 resembles SARS-CoV and MERS-CoV with regard tohigher fatality rates in males, and in the older population with comorbidities. The invasion-mechanism of SARS-CoV-2 and SARS-CoV, involves binding of its spike protein with angiotensin-converting enzyme 2 (ACE2) receptors; MERS-CoV utilizes dipeptidyl peptidase 4 (DPP4), whereas H1N1 influenza is equipped with hemagglutinin protein. The viral infections-mediated immunomodulation, and progressive inflammatory state may affect the functions of several other organs. Although no effective commercial vaccine is available for any of the viruses, those against SARS-CoV-2 are being developed at an unprecedented speed. Until now, only Pfizer/BioNTech's vaccine has received temporary authorization from the UK Medicines and Healthcare products Regulatory Agency. Given the frequent emergence of viral pandemics in the 21st century, proper understanding of their characteristics and modes of action are essential to address the immediate and long-term health consequences.

Association between Prolonged Intermittent Renal Replacement Therapy and All-Cause Mortality in COVID-19 Patients Undergoing Invasive Mechanical Ventilation: A Retrospective Cohort Study

Background

The mortality rate of critically ill patients with coronavirus disease 2019 (COVID-19) was high. We aimed to assess the association between prolonged intermittent renal replacement therapy (PIRRT) and mortality in patients with COVID-19 undergoing invasive mechanical ventilation.

Methods

This retrospective cohort study included all COVID-19 patients receiving invasive mechanical ventilation between February 12 and March 2, 2020. All patients were followed until death or March 28, and all survivors were followed for at least 30 days.

Results

For 36 hospitalized COVID-19 patients receiving invasive mechanical ventilation, the mean age was 69.4 (±10.8) years, and 30 patients (83.3%) were men. Twenty-two (61.1%) patients received PIRRT (PIRRT group), and 14 cases (38.9%) were managed with conventional strategy (non-PIRRT group). There were no differences in age, sex, comorbidities, complications, treatments, and most of the laboratory findings. During the median follow-up period of 9.5 (interquartile range 4.3–33.5) days, 13 of 22 (59.1%) patients in the PIRRT group and 11 of 14 (78.6%) patients in the non-PIRRT group died. Kaplan-Meier analysis demonstrated prolonged survival in patients in the PIRRT group compared with that in the non-PIRRT group (p = 0.042). The association between PIRRT and a reduced risk of mortality remained significant in 3 different models, with adjusted hazard ratios varying from 0.332 to 0.398. Increased IL–2 receptor, TNF-α, procalcitonin, prothrombin time, and NT-proBNP levels were significantly associated with an increased risk of mortality in patients with PIRRT.

Conclusion

PIRRT may be beneficial for the treatment of COVID-19 patients with invasive mechanical ventilation. Further prospective multicenter studies with larger sample sizes are required.

T cell responses in patients with COVID-19

The role of T cells in the resolution or exacerbation of COVID-19, as well as their potential to provide long-term protection from reinfection with SARS-CoV-2, remains debated. Nevertheless, recent studies have highlighted various aspects of T cell responses to SARS-CoV-2 infection that are starting to enable some general concepts to emerge.

Human Organs-on-Chips for Virology

While conventional in vitro culture systems and animal models have been used to study the pathogenesis of viral infections and to facilitate development of vaccines and therapeutics for viral diseases, models that can accurately recapitulate human responses to infection are still lacking. Human organ-on-a-chip (Organ Chip) microfluidic culture devices that recapitulate tissue–tissue interfaces, fluid flows, mechanical cues, and organ-level physiology have been developed to narrow the gap between in vitro experimental models and human pathophysiology. Here, we describe how recent developments in Organ Chips have enabled re-creation of complex pathophysiological features of human viral infections in vitro.

Microfluidic Organ Chip culture devices are emerging alternatives to conventional in vitro and animal models due to their ability to replicate many structural and functional features of human physiology and disease states.

Recent innovations demonstrate that Organ Chip technology is a promising strategy for virology studies where there have been successes in reproducing various viral disease phenotypes.

Organ Chips have enabled investigation of many aspects of viral infection, including virus–host interactions, viral therapy-resistance evolution, and development of new antiviral therapeutics, as well as underlying pathogenesis.

As Organ Chip-based assays provide accessibility to study virus-induced diseases in real time and at high resolution, they can open new avenues to uncover viral pathogenesis in a human-relevant environment and may eventually enable development of novel therapeutics and vaccines.

Viral genomics in Ebola virus research

Filoviruses such as Ebola virus continue to pose a substantial health risk to humans. Advances in the sequencing and functional characterization of both pathogen and host genomes have provided a wealth of knowledge to clinicians, epidemiologists and public health responders during outbreaks of high-consequence viral disease. Here, we describe how genomics has been historically used to investigate Ebola virus disease outbreaks and how new technologies allow for rapid, large-scale data generation at the point of care. We highlight how genomics extends beyond consensus-level sequencing of the virus to include intra-host viral transcriptomics and the characterization of host responses in acute and persistently infected patients. Similar genomics techniques can also be applied to the characterization of non-human primate animal models and to known natural reservoirs of filoviruses, and metagenomic sequencing can be the key to the discovery of novel filoviruses. Finally, we outline the importance of reverse genetics systems that can swiftly characterize filoviruses as soon as their genome sequences are available.

Annexin A2 depletion exacerbates the intracerebral microhemorrhage induced by acute rickettsia and Ebola virus infections

Intracerebral microhemorrhages (CMHs) are small foci of hemorrhages in the cerebrum. Acute infections induced by some intracellular pathogens, including rickettsia, can result in CMHs. Annexin a2 (ANXA2) has been documented to play a functional role during intracellular bacterial adhesion. Here we report that ANXA2-knockout (KO) mice are more susceptible to CMHs in response to rickettsia and Ebola virus infections, suggesting an essential role of ANXA2 in protecting vascular integrity during these intracellular pathogen infections. Proteomic analysis via mass spectrometry of whole brain lysates and brain-derived endosomes from ANXA2-KO and wild-type (WT) mice post-infection with R. australis revealed that a variety of significant proteins were differentially expressed, and the follow-up function enrichment analysis had identified several relevant cell-cell junction functions. Immunohistology study confirmed that both infected WT and infected ANXA2-KO mice were subjected to adherens junctional protein (VE-cadherin) damages. However, key blood-brain barrier (BBB) components, tight junctional proteins ZO-1 and occludin, were disorganized in the brains from R. australis-infected ANXA2-KO mice, but not those of infected WT mice. Similar ANXA2-KO dependent CMHs and fragments of ZO-1 and occludin were also observed in Ebola virus-infected ANXA2-KO mice, but not found in infected WT mice. Overall, our study revealed a novel role of ANXA2 in the formation of CMHs during R. australis and Ebola virus infections; and the underlying mechanism is relevant to the role of ANXA2-regulated tight junctions and its role in stabilizing the BBB in these deadly infections.

Bacillus paranthracis Isolate from Blood of Fatal Ebola Virus Disease Case

A Bacillus paranthracis isolate was cultured from the blood of a fatal Ebola virus disease (EVD) case in Liberia and was identified by whole genome sequencing. Although B. paranthracis has only recently been described and is poorly characterized, this case may represent the bacterial co-infection of an EVD patient.

Epitopes of Naturally Acquired and Vaccine-Induced Anti-Ebola Virus Glycoprotein Antibodies in Single Amino Acid Resolution

The Ebola virus (EBOV) can cause severe infections in humans, leading to a fatal outcome in a high percentage of cases. Neutralizing antibodies against the EBOV surface glycoprotein (GP) can prevent infections, demonstrating a straightforward way for an efficient vaccination strategy. Meanwhile, many different anti-EBOV antibodies have been identified, whereas the exact binding epitopes are often unknown. Here, the analysis of serum samples from an EBOV vaccine trial with the recombinant vesicular stomatitis virus-Zaire ebolavirus (rVSV-ZEBOV) and an Ebola virus disease survivor, using high-density peptide arrays, is presented. In this proof-of-principle study, distinct IgG and IgM antibodies binding to different epitopes of EBOV GP is detected: By mapping the whole GP as overlapping peptide fragments, new epitopes and confirmed epitopes from the literature are found. Furthermore, the highly selective binding epitope of a neutralizing monoclonal anti-EBOV GP antibody could be validated. This shows that peptide arrays can be a valuable tool to study the humoral immune response to vaccines in patients and to support Ebola vaccine development.

Impact of Intravenous Fluid Therapy on Survival Among Patients With Ebola Virus Disease: An International Multisite Retrospective Cohort Study

BACKGROUND

Intravenous fluid (IVF) is a frequently recommended intervention in Ebola virus disease (EVD), yet its impact on patient outcomes remains unclear.

METHODS

This retrospective cohort study evaluated patients with EVD admitted to 5 Ebola treatment units (ETUs) in West Africa. The primary outcome was the difference in 28-day survival between cases treated and not treated with IVF. To control for demographic and clinical factors related to both IVF exposure and survival, cases were compared using propensity score matching. To control for time-varying patient and treatment factors over the course of ETU care, a marginal structural proportional hazards model (MSPHM) with inverse probability weighting was used to assess for 28-day survival differences.

RESULTS

Among 424 EVD-positive cases with data for analysis, 354 (83.5%) were treated with IVF at some point during their ETU admission. Overall, 146 (41.3%) cases treated with IVF survived, whereas 31 (44.9%) cases not treated with any IVF survived (P = .583). Matched propensity score analysis found no significant difference in 28-day survival between cases treated and not treated with IVF during their first 24 and 48 hours of care. Adjusted MSPHM survival analyses also found no significant difference in 28-day survival for cases treated with IVF (27.3%) compared to those not treated with IVF (26.9%) during their entire ETU admission (P = .893).

CONCLUSIONS

After adjustment for patient- and treatment-specific time-varying factors, there was no significant difference in survival among patients with EVD treated with IVF as compared to those not treated with IVF.

Ebola virus disease

Ebola virus disease (EVD) is a severe and frequently lethal disease caused by Ebola virus (EBOV). EVD outbreaks typically start from a single case of probable zoonotic transmission, followed by human-to-human transmission via direct contact or contact with infected bodily fluids or contaminated fomites. EVD has a high case-fatality rate; it is characterized by fever, gastrointestinal signs and multiple organ dysfunction syndrome. Diagnosis requires a combination of case definition and laboratory tests, typically real-time reverse transcription PCR to detect viral RNA or rapid diagnostic tests based on immunoassays to detect EBOV antigens. Recent advances in medical countermeasure research resulted in the recent approval of an EBOV-targeted vaccine by European and US regulatory agencies. The results of a randomized clinical trial of investigational therapeutics for EVD demonstrated survival benefits from two monoclonal antibody products targeting the EBOV membrane glycoprotein. New observations emerging from the unprecedented 2013-2016 Western African EVD outbreak (the largest in history) and the ongoing EVD outbreak in the Democratic Republic of the Congo have substantially improved the understanding of EVD and viral persistence in survivors of EVD, resulting in new strategies toward prevention of infection and optimization of clinical management, acute illness outcomes and attendance to the clinical care needs of patients.

Ebola Hemorrhagic Shock Syndrome-on-a-Chip

Ebola virus, for which we lack effective countermeasures, causes hemorrhagic fever in humans, with significant case fatality rates. Lack of experimental human models for Ebola hemorrhagic fever is a major obstacle that hinders the development of treatment strategies. Here, we model the Ebola hemorrhagic syndrome in a microvessel-on-a-chip system and demonstrate its applicability to drug studies. Luminal infusion of Ebola virus-like particles leads to albumin leakage from the engineered vessels. The process is mediated by the Rho/ROCK pathway and is associated with cytoskeleton remodeling. Infusion of Ebola glycoprotein (GP_1,2) generates a similar phenotype, indicating the key role of GP_1,2 in this process. Finally, we measured the potency of a recently developed experimental drug FX06 and a novel drug candidate, melatonin, in phenotypic rescue. Our study confirms the effects of FX06 and identifies melatonin as an effective, safe, inexpensive therapeutic option that is worth investigating in animal models and human trials.

Ebola virus disease: An emerging and re-emerging viral threat

The genus Ebolavirus from the family Filoviridae is composed of five species including Sudan ebolavirus, Reston ebolavirus, Bundibugyo ebolavirus, Taï Forest ebolavirus, and Ebola virus (previously known as Zaire ebolavirus). These viruses have a large non-segmented, negative-strand RNA of approximately 19 kb that encodes for glycoproteins (i.e., GP, sGP, ssGP), nucleoproteins, virion proteins (i.e., VP 24, 30,40) and an RNA dependent RNA polymerase. These viruses have become a global health concern because of mortality, their rapid dissemination, new outbreaks in West-Africa, and the emergence of a new condition known as "Post-Ebola virus disease syndrome" that resembles inflammatory and autoimmune conditions such as rheumatoid arthritis, systemic lupus erythematosus and spondyloarthritis with uveitis. However, there are many gaps in the understanding of the mechanisms that may induce the development of such autoimmune-like syndromes. Some of these mechanisms may include a high formation of neutrophil extracellular traps, an uncontrolled "cytokine storm", and the possible formation of auto-antibodies. The likely appearance of autoimmune phenomena in Ebola survivors suppose a new challenge in the management and control of this disease and opens a new field of research in a special subgroup of patients. Herein, the molecular biology, pathogenesis, clinical manifestations, and treatment of Ebola virus disease are reviewed and some strategies for control of disease are discussed.

[Virus specific antibody - based remedies for the urgent prevention and treatment of Ebola virus disease]

The Ebola virus (member of Ebolavirus genus Filoviridae family) is the etiologic agent of extremely hazard human disease with high mortality rates (up to 90%). The most important components of spectrum of therapeutics for special prophylactic and current of disease, caused by Ebola virus, are prepares, based on virus specific antibodies (convalescent's plasma, geterologic immunoglobulins, monoclonal antibodies. The use of different class therapeutics, based on virus specific antibodies, the possible improvements of its composition and strategy of its application for special prophylactic and current of disease, caused by Ebola virus, are considered in this review.

Nanoparticles' interactions with vasculature in diseases

The ever-growing use of inorganic nanoparticles (NPs) in biomedicine provides an exciting approach to develop novel imaging and drug delivery systems, owing to the ease with which these NPs can be functionalized to cater to various applications. In cancer therapeutics, nanomedicine generally relies on the enhanced permeability and retention (EPR) effect observed in tumour vasculature to deliver anti-cancer drugs across the endothelium. However, such a phenomenon is dependent on the tumour microenvironment and is not consistently observed in all tumour types, thereby limiting drug transport to the tumour site. On the other hand, there is a rise in utilizing inorganic NPs to intentionally induce endothelial leakiness, creating a window of opportunity to control drug delivery across the endothelium. While this active targeting approach creates a similar phenomenon compared to the EPR effect arising from tumour tissues, its drug delivery applications extend beyond cancer therapeutics and into other vascular-related diseases. In this review, we summarize the current findings of the EPR effect and assess its limitations in the context of anti-cancer drug delivery systems. While the EPR effect offers a possible route for drug passage, we further explore alternative uses of NPs to create controllable endothelial leakiness within short exposures, a phenomenon we coined as nanomaterial-induced endothelial leakiness (NanoEL). Furthermore, we discuss the main mechanistic features of the NanoEL effect that make it unique from conventionally established endothelial leakiness in homeostatic and pathologic conditions, as well as examine its potential applicability in vascular-related diseases, particularly cancer. Therefore, this new paradigm changes the way inorganic NPs are currently being used for biomedical applications.

Assessing Viral Transfer During Doffing of Ebola-Level Personal Protective Equipment in a Biocontainment Unit

Background

Personal protective equipment (PPE) protects healthcare workers (HCWs) caring for patients with Ebola virus disease (EVD), and PPE doffing is a critical point for preventing viral self-contamination. We assessed contamination of skin, gloves, and scrubs after doffing Ebola-level PPE contaminated with surrogate viruses: bacteriophages MS2 and Φ6.

Methods

In a medical biocontainment unit, HCWs (n = 10) experienced in EVD care donned and doffed PPE following unit protocols that incorporate trained observer guidance and alcohol-based hand rub (ABHR). A mixture of Φ6 (enveloped), MS2 (nonenveloped), and fluorescent marker was applied to 4 PPE sites, approximating body fluid viral load (Φ6, 105; MS2, 106). They performed a patient care task, then doffed. Inner gloves, face, hands, and scrubs were sampled for virus, as were environmental sites with visible fluorescent marker.

Results

Among 10 HCWs there was no Φ6 transfer to inner gloves, hands, or face; 1 participant had Φ6 on scrubs at low levels (1.4 × 102). MS2 transfer (range, 101-106) was observed to scrubs (n = 2), hands (n = 1), and inner gloves (n = 7), where it was highest. Most (n = 8) had only 1 positive site. Environmental samples with visible fluorescent marker (n = 21) were negative.

Conclusions

Among experienced HCWs, structured, observed doffing using ABHR protected against hand contamination with enveloped virus. Nonenveloped virus was infrequent on hands and scrubs but common on inner gloves, suggesting that inner gloves, but not necessarily ABHR, protect against hand contamination. Optimizing doffing protocols to protect against all types of viruses may require reinforcing careful handling of scrubs and good glove/hand hygiene with effective agents.

In Vitro and In Vivo Activity of Amiodarone Against Ebola Virus

At the onset of the 2013-2016 epidemic of Ebola virus disease (EVD), no vaccine or antiviral medication was approved for treatment. Therefore, considerable efforts were directed towards the concept of drug repurposing or repositioning. Amiodarone, an approved multi-ion channel blocker for the treatment of cardiac arrhythmia, was reported to inhibit filovirus entry in vitro. Compassionate use of amiodarone in EVD patients indicated a possible survival benefit. In support of further clinical testing, we confirmed anti-Ebola virus activity of amiodarone in different cell types. Despite promising in vitro results, amiodarone failed to protect guinea pigs from a lethal dose of Ebola virus.

Perspectives towards antiviral drug discovery against Ebola virus

Ebola virus disease (EVD), caused by Ebola viruses, resulted in more than 11 500 deaths according to a recent 2018 WHO report. With mortality rates up to 90%, it is nowadays one of the most deadly infectious diseases. However, no Food and Drug Administration‐approved Ebola drugs or vaccines are available yet with the mainstay of therapy being supportive care. The high fatality rate and absence of effective treatment or vaccination make Ebola virus a category‐A biothreat pathogen. Fortunately, a series of investigational countermeasures have been developed to control and prevent this global threat. This review summarizes the recent therapeutic advances and ongoing research progress from research and development to clinical trials in the development of small‐molecule antiviral drugs, small‐interference RNA molecules, phosphorodiamidate morpholino oligomers, full‐length monoclonal antibodies, and vaccines. Moreover, difficulties are highlighted in the search for effective countermeasures against EVD with additional focus on the interplay between available in silico prediction methods and their evidenced potential in antiviral drug discovery.

Vascular Leak and Hypercytokinemia Associated with Severe Fever with Thrombocytopenia Syndrome Virus Infection in Mice

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging viral hemorrhagic fever (VHF) endemic to China, South Korea, Japan, and Vietnam. Here we characterize the pathogenesis and natural history of disease in IFNAR^-/- mice challenged with the HB29 strain of SFTS virus (SFTSV) and demonstrate hallmark features of VHF such as vascular leak and high concentrations of proinflammatory cytokines in blood and tissues. Treatment with FX06, a natural plasmin digest product of fibrin in clinical development as a treatment for vascular leak, reduced vascular permeability associated with SFTSV infection but did not significantly improve survival outcome. Further studies are needed to assess the role of vascular compromise in the SFTS disease process modeled in IFNAR^-/- mice.