scholarly journals An Ebola virus disease model with fear and environmental transmission dynamics

2021 ◽  
Author(s):  
M.L. Juga ◽  
F. Nyabadza ◽  
F. Chirove
Keyword(s):  
Disease Transmission ◽  
Ebola Virus ◽  
Virus Disease ◽  
Case Fatality ◽  
Control Measures ◽  
Transmission Dynamics ◽  
Ebola Virus Disease ◽  
Fear Of Death ◽  
List Type ◽  
Environmental Transmission

ABSTRACTRecent Ebola virus disease (EVD) outbreaks have been limited not only to the interactions between humans but also to the complex interplay of the environment, human and socio-economic factors. Changes in human behaviour as a result of fear can also affect disease transmission dynamics. In this paper, a compartmental model is used to study the dynamics of EVD incorporating fear and environmental transmission. We formulate a fear dependent contact rate function to measure the rate of person to person, as well as pathogen to person transmissions. The epidemic threshold and the model equilibria are determined and, their stabilities are analysed. The model is validated by fitting it to data from the 2019 and 2020 EVD outbreaks in the Democratic Republic of Congo. Our results suggest that the fear of death from EVD may reduce the transmission and aid the control of the disease, but it is not sufficient to eradicate the disease. Policymakers need to also implement other control measures such as case finding, media campaigns, Quarantine and increase in the number of beds in the Ebola treatment centers, good laboratory services, safe burials and social mobilisation, to eradicate the disease.HighlightsDue to its high case fatality rate, EVD undoubtedly instills fear in the inhabitants of any affected community.We propose an Ebola model with fear, which considers the pathogens in the environment to quantify the effect of fear and environmental transmission on the EVD disease dynamics.The fear of death from Ebola is proportional to the Ebola disease transmission rate.At high levels of fear, the number of EVD cases decrease.

JOINT ESTIMATION OF THE TRANSMISSIBILITY AND SEVERITY OF EBOLA VIRUS DISEASE IN REAL TIME

2017 ◽  
Vol 25 (04) ◽  
pp. 587-603 ◽  
Author(s):  
YUSUKE ASAI ◽  
HIROSHI NISHIURA
Keyword(s):  
Real Time ◽  
Ebola Virus ◽  
Virus Disease ◽  
Critical Role ◽  
Estimation Method ◽  
Case Fatality ◽  
Ascertainment Bias ◽  
Joint Estimation ◽  
Ebola Virus Disease ◽  
Strong Impact

The effective reproduction number [Formula: see text], the average number of secondary cases that are generated by a single primary case at calendar time [Formula: see text], plays a critical role in interpreting the temporal transmission dynamics of an infectious disease epidemic, while the case fatality risk (CFR) is an indispensable measure of the severity of disease. In many instances, [Formula: see text] is estimated using the reported number of cases (i.e., the incidence data), but such report often does not arrive on time, and moreover, the rate of diagnosis could change as a function of time, especially if we handle diseases that involve substantial number of asymptomatic and mild infections and large outbreaks that go beyond the local capacity of reporting. In addition, CFR is well known to be prone to ascertainment bias, often erroneously overestimated. In this paper, we propose a joint estimation method of [Formula: see text] and CFR of Ebola virus disease (EVD), analyzing the early epidemic data of EVD from March to October 2014 and addressing the ascertainment bias in real time. To assess the reliability of the proposed method, coverage probabilities were computed. When ascertainment effort plays a role in interpreting the epidemiological dynamics, it is useful to analyze not only reported (confirmed or suspected) cases, but also the temporal distribution of deceased individuals to avoid any strong impact of time dependent changes in diagnosis and reporting.

scholarly journals Use of Viremia to Evaluate the Baseline Case Fatality Ratio of Ebola Virus Disease and Inform Treatment Studies: A Retrospective Cohort Study

PLoS Medicine ◽  
2015 ◽  
Vol 12 (12) ◽  
pp. e1001908 ◽  
Author(s):  
Oumar Faye ◽  
Alessio Andronico ◽  
Ousmane Faye ◽  
Henrik Salje ◽  
Pierre-Yves Boëlle ◽  
...  
Keyword(s):  
Cohort Study ◽  
Retrospective Cohort Study ◽  
Retrospective Cohort ◽  
Ebola Virus ◽  
Virus Disease ◽  
Case Fatality ◽  
Ebola Virus Disease ◽  
Case Fatality Ratio ◽  
Baseline Case

scholarly journals Effects of vaccines in protecting against Ebola virus disease: protocol for a systematic review

BMJ Open ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. e029617 ◽  
Author(s):  
Lindi Mathebula ◽  
Duduzile Edith Ndwandwe ◽  
Elizabeth Pienaar ◽  
Charles Shey Wiysonge
Keyword(s):  
Systematic Review ◽  
Ebola Virus ◽  
Virus Disease ◽  
Data Extraction ◽  
Case Fatality ◽  
Fixed Effect Model ◽  
Ebola Virus Disease ◽  
Pool Data ◽  
Cochrane Central Register ◽  
Clinical Trial Registry

IntroductionEbola virus disease is one of the most devastating infectious diseases in the world with up to 90% case fatality observed. There are at least 13 candidate vaccines developed and being tested to prevent the occurrence of the Ebola virus disease. While none of these candidate vaccines has received regulatory approval for use, one candidate vaccine (rVSVΔG-ZEBOV-GP) has been granted access for emergency use. Two other candidate vaccines (GamEvac-Combi and Ad5-EBOV) have been licensed for emergency use in their countries of origin. The objective of this systematic review is to summarise the effects of the Ebola candidate vaccines in humans.Methods and analysisWe will search for potentially eligible studies, with no language or date restrictions, in the Cochrane Central Register of Controlled Trials, PubMed, Scopus, the WHO International Clinical Trial Registry Platform, and reference lists of relevant publications. The Cochrane Database of Systematic Reviews (CDSR) and the Database of Abstracts of Reviews of Effect (DARE) will be searched for related reviews. Two review authors will independently screen search records, assess study eligibility, perform data extraction, and assess the risk of bias; and reconcile their findings. We will pool data from similar studies using Mantel-Haenszel’s fixed-effect model.Ethics and disseminationThis study is exempted from ethical consideration since the data collected are publicly available and at no point will confidential information from human participants be used. We will disseminate our results through publications in peer-reviewed journals and relevant conferences.PROSPERO registration numberCRD42018110505.

The Epidemiological Presentation Pattern of Ebola Virus Disease Outbreaks: Changes from 1976 to 2019

2020 ◽  
Vol 35 (3) ◽  
pp. 247-253
Author(s):  
Pedro Arcos González ◽  
Ángel Fernández Camporro ◽  
Anneli Eriksson ◽  
Carmen Alonso Llada
Keyword(s):  
At Risk ◽  
Ebola Virus ◽  
Virus Disease ◽  
Disease Outbreaks ◽  
Case Fatality ◽  
Ebola Virus Disease ◽  
World Health ◽  
Study Objective ◽  
Population At Risk ◽  
Case Fatality Ratio

AbstractIntroduction:Ebola Virus Disease (EVD) is the international health emergency paradigm due to its epidemiological presentation pattern, impact on public health, resources necessary for its control, and need for a national and international response.Study Objective:The objective of this work is to study the evolution and progression of the epidemiological presentation profile of Ebola disease outbreaks since its discovery in 1976 to the present, and to explore the possible reasons for this evolution from different perspectives.Methods:Retrospective observational study of 38 outbreaks of Ebola disease occurred from 1976 through 2019, excluding laboratory accidents. United Nations agencies and programs; Ministries of Health; the US Centers for Disease Control and Prevention (CDC); ReliefWeb; emergency nongovernmental organizations; and publications indexed in PubMed, EmBase, and Clinical Key have been used as sources of data. Information on the year of the outbreak, date of beginning and end, duration of the outbreak in days, number of cases, number of deaths, population at risk, geographic extension affected in Km2, and time of notification of the first cases to the World Health Organization (WHO) have been searched and analyzed.Results:Populations at risk have increased (P = .024) and the geographical extent of Ebola outbreaks has grown (P = .004). Reporting time of the first cases of Ebola to WHO has been reduced (P = .017) and case fatality (P = .028) has gone from 88% to 62% in the period studied. There have been differences (P = .04) between the outbreaks produced by the Sudan and Zaire strains of the virus, both in terms of duration and case fatality ratio (Sudan strain 74.5 days on average and 62.7% of case fatality ratio versus Zaire strain with 150 days on average and 55.4% case fatality ratio).Conclusion:There has been a change in the epidemiological profile of the Ebola outbreaks from 1976 through 2019 with an increase in the geographical extent of the outbreaks and the population at risk, as well as a significant decrease in the outbreaks case fatality rate. There have been advances in the detection and management capacity of outbreaks, and the notification time to the WHO has been reduced. However, there are social, economic, cultural, and political obstacles that continue to greatly hinder a more efficient epidemiological approach to Ebola disease, mainly in Central Africa.

Modeling transmission dynamics of Ebola virus disease

2017 ◽  
Vol 10 (04) ◽  
pp. 1750057 ◽  
Author(s):  
Mudassar Imran ◽  
Adnan Khan ◽  
Ali R. Ansari ◽  
Syed Touqeer Hussain Shah
Keyword(s):  
Ebola Virus ◽  
Virus Disease ◽  
Control Strategies ◽  
Transmission Dynamics ◽  
Ebola Virus Disease ◽  
Transmission Model ◽  
Globally Asymptotically Stable ◽  
Dynamical Systems Analysis ◽  
Number Formula ◽  
Disease Free

Ebola virus disease (EVD) has emerged as a rapidly spreading potentially fatal disease. Several studies have been performed recently to investigate the dynamics of EVD. In this paper, we study the transmission dynamics of EVD by formulating an SEIR-type transmission model that includes isolated individuals as well as dead individuals that are not yet buried. Dynamical systems analysis of the model is performed, and it is consequently shown that the disease-free steady state is globally asymptotically stable when the basic reproduction number, [Formula: see text] is less than unity. It is also shown that there exists a unique endemic equilibrium when [Formula: see text]. Using optimal control theory, we propose control strategies, which will help to eliminate the Ebola disease. We use data fitting on models, with and without isolation, to estimate the basic reproductive numbers for the 2014 outbreak of EVD in Liberia and Sierra Leone.

scholarly journals Ocular Manifestations of Ebola Virus Disease: An Ophthalmologist’s Guide to Prevent Infection and Panic

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Enzo Maria Vingolo ◽  
Giuseppe Alessio Messano ◽  
Serena Fragiotta ◽  
Leopoldo Spadea ◽  
Stefano Petti
Keyword(s):  
Ebola Virus ◽  
Virus Disease ◽  
Clinical Signs ◽  
Case Fatality ◽  
Hemorrhagic Fever ◽  
Ebola Virus Disease ◽  
Ocular Manifestations ◽  
Ebola Hemorrhagic Fever ◽  
Sub Saharan ◽  
The Moment

Ebola virus disease (EVD—formerly known as Ebola hemorrhagic fever) is a severe hemorrhagic fever caused by lipid-enveloped, nonsegmented, negative-stranded RNA viruses belonging to the genusEbolavirus. Case fatality rates may reach up to 76% of infected individuals, making this infection a deadly health problem in the sub-Saharan population. At the moment, there are still no indications on ophthalmological clinical signs and security suggestions for healthcare professionals (doctors and nurses or cooperative persons). This paper provides a short but complete guide to reduce infection risks.

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