Ebolavirus in West Africa, and the use of experimental therapies or vaccines

Ebola outbreak in Nigeria: perceptions from commercial motorcyclists and passengers in Ibadan, Nigeria

The outbreak of deadliest and most widespread Ebola virus disease (EVD) in West African countries was not only unexpected but also sudden in places like Nigeria. The epidemic was an indication of weak health systems characterised by inadequate precautions and low knowledge of containment. Although Nigeria was able to contain EVD much earlier, people's perception, which also influenced their responses, might enhance the spread and retard containment. This study utilized 25 in-depth interviews conducted with commercial motorcycle-taxi (Okada) riders in key locations in Ibadan, Oyo state, to document their perception about EVD outbreak. Series of sociocultural practices such as handshaking, hugging and embracement identified were favourable to transmission of EVD and affected containment. Regular handwashing was difficult and not cost-effective to practice. The perceived trust in God's intervention could make treatment seeking and prevention slower to achieve. The potential of sociocultural practices, such as handshaking and hugging, as driver for transmission of EVD may influence the perception of motorcycle-taxi riders in the prevention and containment activities in Nigeria. Hence, understanding people's perception on handwashing practices, hugging and butchering of bushmeat should be given priority in designing programmes of EVD prevention and control in Nigeria.

Modeling the Ebola zoonotic dynamics: Interplay between enviroclimatic factors and bat ecology

Understanding Ebola necessarily requires the characterization of the ecology of its main enzootic reservoir, i.e. bats, and its interplay with seasonal and enviroclimatic factors. Here we present a SIR compartmental model where we implement a bidirectional coupling between the available resources and the dynamics of the bat population in order to understand their migration patterns. Our compartmental modeling approach and simulations include transport terms to account for bats mobility and spatiotemporal climate variability. We hypothesize that environmental pressure is the main driving force for bats' migration and our results reveal the appearance of sustained migratory waves of Ebola virus infected bats coupled to resources availability. Ultimately, our study can be relevant to predict hot spots of Ebola outbreaks in space and time and suggest conservation policies to mitigate the risk of spillovers.

Reverse Genetics Systems for Filoviruses

Filoviruses are among the most pathogenic viruses known to man. Reverse genetics systems, in particular full-length clone systems, allow the generation of recombinant filoviruses, which can be used to study virus biology, but also for applied uses such as screening for countermeasures. Here we describe the generation of recombinant filoviruses from cDNA.

Health-Care Workers' Perspectives on Ebola Virus Vaccine: A Focus Group and In-Depth Interview Interventional Study

Health-care workers (HCWs) will require Ebola virus vaccine (EVV) when it is introduced because of the high risk of exposure to the disease. Evaluations of factors that facilitate or limit vaccine uptake are critical for a successful vaccine program. Nigerian HCWs were interviewed to evaluate their knowledge, levels of acceptance, determinants of acceptance, and willingness to pay for EVV. The significance level was set at P ≤ 0.05. None of the 193 participating HCWs had correct knowledge of EVV; 34.7% (67/193) of workers thought that EVV was an extract of the serum of Ebola virus patients. About 77.3% (51/66) of workers in a region that reported Ebola cases (Lagos) were willing to be vaccinated, compared with 4.7% (3/61) in Enugu and 13.6% (9/66) in Abia (P = 0.0001). After health education, the proportion of HCWs willing to receive EVV increased (P = 0.006) except for doctors (P < 0.1). The percentage of HCWs willing to pay for EVV was 86.4%, 72.1%, and 59% in Lagos, Enugu, and Abia, respectively. The workers had fears about EVV based on nonfactual assumptions. Therefore, the EVV introduction strategy should include a strong awareness campaign with adequate explanation about the content of EVV.

Treating Ebola patients: a 'bottom up' approach using generic statins and angiotensin receptor blockers

The international community has responded to the Ebola outbreak in West Africa with a 'top down' approach. This has contributed to outbreak control, but has done much less to reduce the high mortality rate in individual patients. Ebola patients experience a breakdown in endothelial barrier integrity that leads to massive fluid losses and vascular collapse. Statins and angiotensin receptor blockers (ARBs) maintain or restore endothelial barrier integrity. Local physicians in Sierra Leone have treated approximately 100 consecutive Ebola patients with atorvastatin and irbesartan, and all but two inadequately treated patients have survived. The results of this experience have not been released and they need to be reviewed and validated. Unlike other treatments that target the Ebola virus itself, this 'bottom up' approach to treatment represents a paradigm shift by targeting the host response to infection. Treatment with these safe, inexpensive generic agents could be implemented readily throughout West Africa.

Cell-cell contact promotes Ebola virus GP-mediated infection

Ebola virus (EBOV) is a highly pathogenic filovirus that causes hemorrhagic fever in humans and animals. Here we provide evidence that cell-cell contact promotes infection mediated by the glycoprotein (GP) of EBOV. Interestingly, expression of EBOV GP alone, even in the absence of retroviral Gag-Pol, is sufficient to transfer a retroviral vector encoding Tet-off from cell to cell. Cell-to-cell infection mediated by EBOV GP is blocked by inhibitors of actin polymerization, but appears to be less sensitive to KZ52 neutralization. Treatment of co-cultured cells with cathepsin B/L inhibitors, or an entry inhibitor 3.47 that targets the receptor NPC1 for virus binding, also blocks cell-to-cell infection. Cell-cell contact also enhances spread of rVSV bearing GP in monocytes and macrophages, the primary targets of natural EBOV infection. Altogether, our study reveals that cell-cell contact promotes EBOV GP-mediated infection, and provides new insight into understanding EBOV spread and viral pathogenesis.

Recent advances in the development of vaccines for Ebola virus disease

Ebola virus is one of the most dangerous microorganisms in the world causing hemorrhagic fevers in humans and non-human primates. Ebola virus (EBOV) is a zoonotic infection, which emerges and re-emerges in human populations. The 2014 outbreak was caused by the Zaire strain, which has a kill rate of up to 90%, though 40% was recorded in the current outbreak. The 2014 outbreak is larger than all 20 outbreaks that have occurred since 1976, when the virus was first discovered. It is the first time that the virus was sustained in urban centers and spread beyond Africa into Europe and USA. Thus far, over 22,000 cases have been reported with about 50% mortality in one year. There are currently no approved therapeutics and preventive vaccines against Ebola virus disease (EVD). Responding to the devastating effe1cts of the 2014 outbreak and the potential risk of global spread, has spurred research for the development of therapeutics and vaccines. This review is therefore aimed at presenting the progress of vaccine development. Results showed that conventional inactivated vaccines produced from EBOV by heat, formalin or gamma irradiation appear to be ineffective. However, novel vaccines production techniques have emerged leading to the production of candidate vaccines that have been demonstrated to be effective in preclinical trials using small animal and non-human primates (NHP) models. Some of the promising vaccines have undergone phase 1 clinical trials, which demonstrated their safety and immunogenicity. Many of the candidate vaccines are vector based such as Vesicular Stomatitis Virus (VSV), Rabies Virus (RABV), Adenovirus (Ad), Modified Vaccinia Ankara (MVA), Cytomegalovirus (CMV), human parainfluenza virus type 3 (HPIV3) and Venezuelan Equine Encephalitis Virus (VEEV). Other platforms include virus like particle (VLP), DNA and subunit vaccines.

Treating the Host Response to Ebola Virus Disease with Generic Statins and Angiotensin Receptor Blockers

Treatments targeting the Ebola virus may eventually be shown to work, but they will not have an impact on overall Ebola mortality in West Africa. Endothelial dysfunction is responsible for the fluid and electrolyte imbalances seen in Ebola patients. Because inexpensive generic statins and angiotensin receptor blockers restore endothelial barrier integrity, they can be used to treat the host response in these patients. In Sierra Leone, approximately 100 Ebola patients were treated with this combination, and reports indicate that survival was greatly improved.

Transport of Ebolavirus Nucleocapsids Is Dependent on Actin Polymerization: Live-Cell Imaging Analysis of Ebolavirus-Infected Cells

BACKGROUND

Transport of ebolavirus (EBOV) nucleocapsids from perinuclear viral inclusions, where they are formed, to the site of budding at the plasma membrane represents an obligatory step of virus assembly. Until now, no live-cell studies on EBOV nucleocapsid transport have been performed, and participation of host cellular factors in this process, as well as the trajectories and speed of nucleocapsid transport, remain unknown.

METHODS

Live-cell imaging of EBOV-infected cells treated with different inhibitors of cellular cytoskeleton was used for the identification of cellular proteins involved in the nucleocapsid transport. EBOV nucleocapsids were visualized by expression of green fluorescent protein (GFP)-labeled nucleocapsid viral protein 30 (VP30) in EBOV-infected cells.

RESULTS

Incorporation of the fusion protein VP30-GFP into EBOV nucleocapsids was confirmed by Western blot and indirect immunofluorescence analyses. Importantly, VP30-GFP fluorescence was readily detectable in the densely packed nucleocapsids inside perinuclear viral inclusions and in the dispersed rod-like nucleocapsids located outside of viral inclusions. Live-cell imaging of EBOV-infected cells revealed exit of single nucleocapsids from the viral inclusions and their intricate transport within the cytoplasm before budding at the plasma membrane. Nucleocapsid transport was arrested upon depolymerization of actin filaments (F-actin) and inhibition of the actin-nucleating Arp2/3 complex, and it was not altered upon depolymerization of microtubules or inhibition of N-WASP. Actin comet tails were often detected at the rear end of nucleocapsids. Marginally located nucleocapsids entered filopodia, moved inside, and budded from the tip of these thin cellular protrusions.

CONCLUSIONS

Live-cell imaging of EBOV-infected cells revealed actin-dependent long-distance transport of EBOV nucleocapsids before budding at the cell surface. These findings provide useful insights into EBOV assembly and have potential application in the development of antivirals.

Animal models for ebolavirus countermeasures discovery: what defines a useful model?

INTRODUCTION

Ebolaviruses are highly pathogenic filoviruses, which cause disease in humans and nonhuman primates (NHP) in Africa. The Zaire ebolavirus outbreak in 2014, which continues to greatly affect Western Africa and other countries to which the hemorrhagic fever was exported due to travel of unsymptomatic yet infected individuals, was complicated by the lack of available licensed vaccines or therapeutics to combat infection. After almost a year of research at an increased pace to find and test vaccines and therapeutics, there is now a deeper understanding of the available disease models for ebolavirus infection. Demonstration of vaccine or therapeutic efficacy in NHP models of ebolavirus infection is crucial to the development and eventual licensure of ebolavirus medical countermeasures, so that safe and effective countermeasures can be accelerated into human clinical trials.

AREAS COVERED

The authors describe ebolavirus hemorrhagic fever (EHF) disease in various animal species: mice, guinea pigs, hamsters, pigs and NHP, to include baboons, marmosets, rhesus and cynomolgus macaques, as well as African green monkeys. Because the NHP models are supremely useful for therapeutics and vaccine testing, emphasis is placed on comparison of these models, and their use as gold-standard models of EHF.

EXPERT OPINION

Animal models of EHF varying from rodents to NHP species are currently under evaluation for their reproducibility and utility for modeling infection in humans. Complete development and licensure of therapeutic agents and vaccines will require demonstration that mechanisms conferring protection in NHP models of infection are predictive of protective responses in humans, for a given countermeasure.

Hegemonic structure of basic, clinical and patented knowledge on Ebola research: a US army reductionist initiative

Background

Ebola hemorrhagic fever (Ebola) is still a highly lethal infectious disease long affecting mainly neglected populations in sub-Saharan Africa. Moreover, this disease is now considered a potential worldwide threat. In this paper, we present an approach to understand how the basic, clinical and patent knowledge on Ebola is organized and intercommunicated and what leading factor could be shaping the evolution of the knowledge translation process for this disease.

Methodology

A combination of citation network analysis; analysis of Medical heading Subject (MeSH) and Gene Ontology (GO) terms, and quantitative content analysis for patents and scientific literature, aimed to map the organization of Ebola research was carried out.

Results

We found six putative research fronts (i.e. clusters of high interconnected papers). Three research fronts are basic research on Ebola virus structural proteins: glycoprotein, VP40 and VP35, respectively. There is a fourth research front of basic research papers on pathogenesis, which is the organizing hub of Ebola research. A fifth research front is pre-clinical research focused on vaccines and glycoproteins. Finally, a clinical-epidemiology research front related to the disease outbreaks was identified. The network structure of patent families shows that the dominant design is the use of Ebola virus proteins as targets of vaccines and other immunological treatments. Therefore, patents network organization resembles the organization of the scientific literature. Specifically, the knowledge on Ebola would flow from higher (clinical-epidemiology) to intermediated (cellular-tissular pathogenesis) to lower (molecular interactions) levels of organization.

Conclusion

Our results suggest a strong reductionist approach for Ebola research probably influenced by the lethality of the disease. On the other hand, the ownership profile of the patent families network and the main researches relationship with the United State Army suggest a strong involvement of this military institution in Ebola research.

Global Access Programs: A Collaborative Approach for Effective Implementation and Management

Global access programs (GAPs) provide access to medicinal products for patients with serious medical conditions and no commercially available treatment options. Providing early access to medicines can be challenging for a pharmaceutical company. The demand for a GAP often occurs at a time when other activities are the prime focus, such as delivery of pivotal clinical trials or gaining of marketing authorization. Furthermore, the skills, experience, and infrastructure necessary to implement and manage a successful GAP vary significantly from those required for regular clinical trial execution, and the regulatory environment presents its own challenges, with regulations often poorly defined and with considerable inter-country variation. This article considers the triggers for early access requests and examines the need for companies to develop a global strategy for GAPs in order to respond appropriately to requests for early access. It also provides a comprehensive overview of the processes for GAP set-up, implementation, management, and closure, along with the considerations affecting the type and scope of GAP, such as demand, regulatory feasibility, license status of the product, drug pricing structure, company strategy, costs, and product supply. Also discussed is the need for appropriate personnel to implement and manage the GAP, and when to consider collaboration with an external GAP provider. In summary, GAPs require careful and efficient planning and management, from set-up to closure. Well-run GAPs provide an ethical and regulatory-compliant pathway for access of new treatments to patients with serious conditions and an unmet medical need.

Human Ebola virus infection in West Africa: a review of available therapeutic agents that target different steps of the life cycle of Ebola virus

The recent outbreak of the human Zaire ebolavirus (EBOV) epidemic is spiraling out of control in West Africa. Human EBOV hemorrhagic fever has a case fatality rate of up to 90%. The EBOV is classified as a biosafety level 4 pathogen and is considered a category A agent of bioterrorism by Centers for Disease Control and Prevention, with no approved therapies and vaccines available for its treatment apart from supportive care. Although several promising therapeutic agents and vaccines against EBOV are undergoing the Phase I human trial, the current epidemic might be outpacing the speed at which drugs and vaccines can be produced. Like all viruses, the EBOV largely relies on host cell factors and physiological processes for its entry, replication, and egress. We have reviewed currently available therapeutic agents that have been shown to be effective in suppressing the proliferation of the EBOV in cell cultures or animal studies. Most of the therapeutic agents in this review are directed against non-mutable targets of the host, which is independent of viral mutation. These medications are approved by the Food and Drug Administration (FDA) for the treatment of other diseases. They are available and stockpileable for immediate use. They may also have a complementary role to those therapeutic agents under development that are directed against the mutable targets of the EBOV.