Ebola

2020 ◽  
pp. 223-240
Author(s):  
Michael B. A. Oldstone
Keyword(s):  
Virus Infection ◽  
West Africa ◽  
Ebola Virus ◽  
Central Africa ◽  
Hemorrhagic Fever ◽  
Natural Reservoir ◽  
Western Africa ◽  
Fruit Bat ◽  
Contaminated Blood ◽  
Ebola Virus Infection

This chapter examines the Ebola virus in detail. Since 1976, with the exception of the 2013–2016 epidemic in West Africa, all outbreaks of Ebola virus infection have occurred in central Africa. The initial 1976 eruption of Ebola in Zaire in central Africa provided lessons for how to control future outbreaks of this disease. Unfortunately, those lessons were not well learned or sufficiently applied to the massive Ebola outbreak that followed in 2013–2016 in western Africa. Ebola virus can spread either through the air or by exposure to contaminated blood of infected humans. The clinical course of Ebola virus infection is that of a severe hemorrhagic fever. An Ebola vaccine was developed and administered to over 40,000 individuals for the 2018–2019 outbreak. However, the vaccine’s effectiveness in the outbreak has not been formally assessed, and critical scientific assessment will be difficult to achieve. Ultimately, Ebola virus remains endemic in Africa. Whether the fruit bat is the only natural reservoir for such viruses, how Ebola is transmitted, and where it lurks are still unresolved.

scholarly journals Seroprevalence of Ebola virus infection in Bombali District, Sierra Leone

2017 ◽  
Author(s):  
Nadege Goumkwa Mafopa ◽  
Gianluca Russo ◽  
Raoul Emeric Guetiya Wadoum ◽  
Emmanuel Iwerima ◽  
Vincent Batwala ◽  
...  
Keyword(s):  
Immune Response ◽  
Virus Infection ◽  
West Africa ◽  
Sierra Leone ◽  
Ebola Virus ◽  
Virus Disease ◽  
Asymptomatic Infection ◽  
Ebola Virus Disease ◽  
Efficient Immune Response ◽  
Ebola Virus Infection

A serosurvey of anti-Ebola Zaire virus nucleoprotein IgG prevalence was carried out among Ebola virus disease survivors and their Community Contacts in Bombali District, Sierra Leone. Our data suggest that the specie of Ebola virus (Zaire) responsible of the 2013-2016 epidemic in West Africa may cause mild or asymptomatic infection in a proportion of cases, possibly due to an efficient immune response.

scholarly journals Passive Transfer of Antibodies Protects Immunocompetent and Immunodeficient Mice against Lethal Ebola Virus Infection without Complete Inhibition of Viral Replication

2001 ◽  
Vol 75 (10) ◽  
pp. 4649-4654 ◽  
Author(s):  
Manisha Gupta ◽  
Siddhartha Mahanty ◽  
Mike Bray ◽  
Rafi Ahmed ◽  
Pierre E. Rollin
Keyword(s):  
Virus Infection ◽  
Viral Replication ◽  
Ebola Virus ◽  
Protective Efficacy ◽  
Hemorrhagic Fever ◽  
Passive Transfer ◽  
Immune Serum ◽  
Immunodeficient Mice ◽  
Ebola Hemorrhagic Fever ◽  
Ebola Virus Infection

ABSTRACT Ebola hemorrhagic fever is a severe, usually fatal illness caused by Ebola virus, a member of the filovirus family. The use of nonhomologous immune serum in animal studies and blood from survivors in two anecdotal reports of Ebola hemorrhagic fever in humans has shown promise, but the efficacy of these treatments has not been demonstrated definitively. We have evaluated the protective efficacy of polyclonal immune serum in a mouse model of Ebola virus infection. Our results demonstrate that mice infected subcutaneously with live Ebola virus survive infection and generate high levels of anti-Ebola virus immunoglobulin G (IgG). Passive transfer of immune serum from these mice before challenge protected upto 100% of naive mice against lethal Ebola virus infection. Protection correlated with the level of anti-Ebola virus IgG titers, and passive treatment with high-titer antiserum was associated with a delay in the peak of viral replication. Transfer of immune serum to SCID mice resulted in 100% survival after lethal challenge with Ebola virus, indicating that antibodies alone can protect from lethal disease. Thus antibodies suppress or delay viral growth, provide protection against lethal Ebola virus infection, and may not require participation of other immune components for protection.

scholarly journals A THEORETICAL STUDY ON FRACTIONAL EBOLA HEMORRHAGIC FEVER MODEL

Fractals ◽  
2021 ◽  
Author(s):  
SHAHER MOMANI ◽  
R. P. CHAUHAN ◽  
SUNIL KUMAR ◽  
SAMIR HADID
Keyword(s):  
Virus Infection ◽  
Ebola Virus ◽  
Virus Disease ◽  
Numerical Technique ◽  
Disease Model ◽  
Hemorrhagic Fever ◽  
Health Concern ◽  
Ebola Hemorrhagic Fever ◽  
Conformable Derivatives ◽  
Ebola Virus Infection

The Ebola virus infection (EVI), generally known as Ebola hemorrhagic fever, is a major health concern. The occasional outbreaks of virus occur primarily in certain parts of Africa. Many researches have been devoted to the study of the Ebola virus disease. In this paper, we have taken susceptible-infected-recovered-deceased-environment (SIRDP) system to investigate the dynamics of Ebola virus infection. We adopted fractional operators for a better illustration of model dynamics and memory effects. Initially, the Ebola disease model is modified with Caputo–Fabrizio arbitrary operator in Caputo sense (CFC) and we employed the fixed-point results for the existence and uniqueness of the solution of the fractional system. Further, we adopted the arbitrary fractional conformable and [Formula: see text]-conformable derivatives to the alternative representation of the model. For the numerical approximation of the system, we show a numerical technique based on the fundamental theorem of fractional calculus for CFC derivative and a numerical scheme called the Adams–Moulton for conformable derivatives. Finally, for the validation of theoretical results, the numerical simulations are displayed.

scholarly journals Identification of Protective Epitopes on Ebola Virus Glycoprotein at the Single Amino Acid Level by Using Recombinant Vesicular Stomatitis Viruses

2003 ◽  
Vol 77 (2) ◽  
pp. 1069-1074 ◽  
Author(s):  
Ayato Takada ◽  
Heinz Feldmann ◽  
Ute Stroeher ◽  
Mike Bray ◽  
Shinji Watanabe ◽  
...  
Keyword(s):  
Amino Acid ◽  
Virus Infection ◽  
Ebola Virus ◽  
Hemorrhagic Fever ◽  
Passive Transfer ◽  
Single Amino Acid ◽  
Virus Glycoprotein ◽  
Vesicular Stomatitis ◽  
Encoding Gene ◽  
Ebola Virus Infection

ABSTRACT Ebola virus causes lethal hemorrhagic fever in humans, but currently there are no effective vaccines or antiviral compounds for this infectious disease. Passive transfer of monoclonal antibodies (MAbs) protects mice from lethal Ebola virus infection (J. A. Wilson, M. Hevey, R. Bakken, S. Guest, M. Bray, A. L. Schmaljohn, and M. K. Hart, Science 287:1664-1666, 2000). However, the epitopes responsible for neutralization have been only partially characterized because some of the MAbs do not recognize the short synthetic peptides used for epitope mapping. To identify the amino acids recognized by neutralizing and protective antibodies, we generated a recombinant vesicular stomatitis virus (VSV) containing the Ebola virus glycoprotein-encoding gene instead of the VSV G protein-encoding gene and used it to select escape variants by growing it in the presence of a MAb (133/3.16 or 226/8.1) that neutralizes the infectivity of the virus. All three variants selected by MAb 133/3.16 contained a single amino acid substitution at amino acid position 549 in the GP2 subunit. By contrast, MAb 226/8.1 selected three different variants containing substitutions at positions 134, 194, and 199 in the GP1 subunit, suggesting that this antibody recognized a conformational epitope. Passive transfer of each of these MAbs completely protected mice from a lethal Ebola virus infection. These data indicate that neutralizing antibody cocktails for passive prophylaxis and therapy of Ebola hemorrhagic fever can reduce the possibility of the emergence of antigenic variants in infected individuals.

scholarly journals Pooled Analysis of the Accuracy of Xpert Ebola Assay for Diagnosing Ebola Virus Infection

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Zhi-Yong Pan ◽  
Yan-Jun Wu ◽  
Ye-Xian Zeng ◽  
Hao Lin ◽  
Tian-Ao Xie ◽  
...  
Keyword(s):  
Virus Infection ◽  
Likelihood Ratio ◽  
Ebola Virus ◽  
Meta Analysis ◽  
Positive Likelihood Ratio ◽  
Negative Likelihood Ratio ◽  
Hemorrhagic Fever ◽  
Pooled Analysis ◽  
Rt Pcr ◽  
Ebola Virus Infection

Background. West Africa has witnessed the unprecedented outbreak of Ebola virus disease (EVD). The Ebola virus (EBOV) can cause Ebola hemorrhagic fever, which is documented as the most deadly viral hemorrhagic fever in the world. RT-PCR had been suggested to be employed in the detection of Ebola virus; however, this method has high requirements for laboratory equipment and takes a long time to determine Ebola infection. Although Xpert Ebola is a fast and simple instrument for the detection of Ebola virus, its effect is still unclear. This study is aimed at evaluating the accuracy of Xpert Ebola in diagnosing Ebola virus infection. Methods. Using the keywords “Xpert” and “Ebola virus”, relevant studies were retrieved from the database of PubMed, Embase, Web of Science, and Cochrane. RT-PCR was employed as a reference standard to evaluate whether the study is eligible to be included in the meta-analysis. Data from these included studies were extracted by two independent assessors and were then analyzed by the Meta-DiSc 1.4 software to produce the heterogeneity of sensitivity (SEN), specificity (SP), positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic advantage ratio (DOR) of the study. The results of pooled analysis were plotted, together with the summary receiver operating characteristic (SROC) curve plotted by calculating the area under the curve (AUC). Generated pooled summary estimates (95% CIs) were calculated for the evaluation of the overall accuracy of this study. Results. Five fourfold tables were made from the four studies that were included in the meta-analysis. The pooled sensitivity of Xpert Ebola was 0.98 (95% confidence interval (CI) (0.95, 0.99)), and the pooled specificity was 0.98 (95% CI (0.97, 0.99)). The pooled values of positive likelihood ratio was 53.91 (95% CI (12.82, 226.79)), with negative likelihood ratio being 0.04 (95% CI (0.02, 0.08)) and diagnostic odds ratio being 2649.45 (95% CI (629.61, 11149.02)). The AUC was 0.9961. Conclusions. Compared with RT-PCR, Xpert Ebola has high sensitivity and specificity. Therefore, it is a valued alternative method for the clinical diagnosis of Ebola virus infection. However, the Xpert Ebola test is a qualitative test that does not provide quantitative testing of EBOV concentration. Whether it can completely replace other methods or not calls for further evidences.

scholarly journals C-Type Lectins DC-SIGN and L-SIGN Mediate Cellular Entry by Ebola Virus in cis and in trans

2002 ◽  
Vol 76 (13) ◽  
pp. 6841-6844 ◽  
Author(s):  
Carmen P. Alvarez ◽  
Fátima Lasala ◽  
Jaime Carrillo ◽  
Oscar Muñiz ◽  
Angel L. Corbí ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Virus Infection ◽  
Receptor Binding ◽  
Ebola Virus ◽  
Hemorrhagic Fever ◽  
In Trans ◽  
Cellular Entry ◽  
In Cis ◽  
Ebola Virus Infection

ABSTRACT Ebola virus is a highly lethal pathogen responsible for several outbreaks of hemorrhagic fever. Here we show that the primate lentiviral binding C-type lectins DC-SIGN and L-SIGN act as cofactors for cellular entry by Ebola virus. Furthermore, DC-SIGN on the surface of dendritic cells is able to function as a trans receptor, binding Ebola virus-pseudotyped lentiviral particles and transmitting infection to susceptible cells. Our data underscore a role for DC-SIGN and L-SIGN in the infective process and pathogenicity of Ebola virus infection.

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