Global Epidemic of Ebola Virus Disease and the Importation Risk into China: An Assessment Based on the Risk Matrix Method

Objective To analyze the global epidemic status of the Ebola virus disease(EVD) and assess the importation risk into China.Methods Data from World Health Organization reports were used. We described the global epidemic status of EVD from 1976–2021, and assessed and ranked the importation risk of EVD from the diseaseoutbreaking countries into China using the risk matrix and Borda count methods, respectively.Results From 1976–2021, EVD mainly occurred in western and central Africa, with the highest cumulative number of cases(14,124 cases) in Sierra Leone, and the highest cumulative fatality rate(85%) in the Congo. Outbreaks of EVD have occurred in the Democratic Republic of the Congo and Guinea since 2018. The importation risk into China varies across countries with outbreaks of disease.The Democratic Republic of the Congo had an extremely high risk(23 Borda points), followed by Guinea and Liberia. Countries with a moderate importation risk were Nigeria, Uganda, Congo, Sierra Leone,Mali, and Gabon, while countries with a low importation risk included Sudan, Senegal, and Co te d’Ivoire.Conclusion China is under the risk of EVD importation with the globalization and severe epidemic status of EVD. Key attention need to be paid to the Democratic Republic of the Congo, Guinea, and Liberia. Therefore, it is necessary to prevent and prepare in advance for importation risk in China.

Lessons for Epidemic Emergency Policy: A Scoping Review of Ebola and COVID-19 Pandemics in Africa

Ebola Virus Disease (EVD) outbreaks in Central and West Africa 2013-2020 were the deadliest, most intense and most widely spread. On top of this, the novel Corona Virus Disease 2019 (COVID-19) has given us all a new experience. It is imperative to draw lessons to prepare for future disease outbreaks. This was a scoping review, a method that allows the assessment of emerging evidence. The objectives of the review were to 1) describe the manifestation of the epidemics;2) elaborate on the social and economic effects;3) characterize the responses;and 4) draw lessons. The findings show that Ebola risk is permanent and even increasing. The next COVID-19 epidemic is around the corner. For Africa, the situation has been made worse by poverty and fragility of institutions. Africa’s incapacity to manufacture its own vaccines, medicines, diagnostics and protective wear has been detrimental in the management of epidemics. The need for personal and home hygiene has been emphatically brought to attention. The trust in the government and other agencies is the cornerstone in the management of emergencies. The use of armed soldiers should be discouraged, for they scare people from seeking help. It is much better to use trusted local leaders instead of strangers during pandemic emergencies. Understanding the local politics without getting involved in them is essential. It is critical to understand community and individual perception of the risk of the disease in question. Often neglected is the psycho-social aspect, which should be planned early. The science of response measures ought to be explained simply and transparently, as part of risk communication. Emergency funds should be raised, and made easy and quick to disburse. Mechanisms of sharing health technologies and knowledge need to be devised under the UN. People centeredness ought to guide the conduct of trans-border movements and all transactions during pandemics.

An update on the 2014 Ebola outbreak in western Africa

The recent Ebola outbreak in Western Africa was the most devastating outbreak witnessed in recent times,There have been remarkable local and international efforts to control the crisis,Ebola Virus Disease is the focus of immense research activity,The progression of events in the region has been evolving swiftly and it is of paramount importance to the medical community to be acquainted with the situation,Over 28 000 people were inflicted with the condition,over 11 000 have died,Novel data has emerged regarding modes of transmission,providing rationale for recent flare-ups,Similarly,studies on survivors are elucidating the later stages of the disease recovery process,Novel techniques for diagnosis are also discussed,Finally,the current research regarding treatment and vaccine development is reviewed,particularly the implementation of r VSV-ZEBOV vaccination programs.

人和猴的Ebola病毒感染

Ebola病毒为丝状病毒科(Filoviridae),1976年发现于非洲大陆,属“生物安全四级”病原。人类感染主要表现为发热和出血,发病急,病程短,死亡率高,是一种烈性病毒性传染病。1989年10月,由菲律宾运往美国的100只猕猴,突然发病,死亡60只,研究证实为Ebo-la病毒感染,从而引起人们对本病的极大关注。 一、发生与分布 1976年6月～11月间,在苏丹南部和扎伊尔北部同时爆发一种高致死性病毒性出血热。在苏丹,299人发病,死亡155人(病死率53％);在扎伊尔,318人发病,死亡280人(病死率88％)。研究人员从扎伊尔和苏丹的病人体内均分离到病毒。因该病流行于扎伊尔北部Ebola小河流域,故命名为Ebola病毒。之后,非洲其他一些国家,如尼日利尼、中非共和国、肯尼亚、几内亚、加蓬、喀麦隆及乌干达等也相继报道出现本病。泰国、美国、加拿大等国也有本病流行的血清学证据。

The Ebola epidemic is ongoing in West Africa and responses from China are positive

The ongoing Ebola outbreak poses an alarming risk to the countries of West Africa and beyond. On August 8, 2014, the World Health Organization(WHO) declared the cross-country Ebola outbreak a Public Emergency of International Concern. China has had no confirmed cases of Ebola. In this paper, virologic characteristics, pathogenesis, clinical manifestations, laboratory examination and prophylactic vaccines and therapeutic drugs of Ebola are summarized. Importantly, active responses and actions from China are introduced. Moreover, the key issues in the future prevention and control of Ebola were also addressed.

Strategy and technology to prevent hospital-acquired infections:Lessons from SARS,Ebola,and MERS in Asia and West Africa

Hospital-acquired infections(HAIs) are serious problems for healthcare systems, especially in developing countries where public health infrastructure and technology for infection preventions remain undeveloped. Here, we characterized how strategy and technology could be mobilized to improve the effectiveness of infection prevention and control in hospitals during the outbreaks of Ebola, Middle East respiratory syndrome(MERS), and severe acute respiratory syndrome(SARS) in Asia and West Africa. Published literature on the hospital-borne outbreaks of SARS, Ebola, and MERS in Asia and West Africa was comprehensively reviewed. The results showed that healthcare systems and hospital management in affected healthcare facilities had poor strategies and inadequate technologies and human resources for the prevention and control of HAIs, which led to increased morbidity, mortality, and unnecessary costs. We recommend that governments worldwide enforce disaster risk management, even when no outbreaks are imminent. Quarantine and ventilation functions should be taken into consideration in architectural design of hospitals and healthcare facilities. We also recommend that health authorities invest in training healthcare workers for disease outbreak response, as their preparedness is essential to reducing disaster risk.

Ebola Virus Disease: General Characteristics, Thoughts, and Perspectives

In December 2013, a new round of Ebola virus disease （EVD） first occurred in a remote countryside of Guinea and then spread in Guinea, Liberia, Sierra Leone, and Nigeria of West Africa. EVD, caused by Ebolavirus and previously known as Ebola hemorrhagic fever, is an acute infectious disease with fatality rates up to 90%. As of August 22, 2014, the number of suspected and confirmed cases was 2615, causing 1427 deaths[I]. On August 8, 2014, World Health Organization announced the current outbreak in West Africa as an international public health emergency. The global epidemic tendency remains ambiguous to date. In recent years, China closely collaborates with West Africa in labor, business, overseas education, and also sends aid medical team there. Thus, the risk of importing the disease cannot be ignored. We conduct this literature review of epidemiology, pathogen, prophylaxis, and treatment to provide evidence for controlling the risk and carrying out effective interventions.

Ebola virus disease: past, present and future

Ebola virus disease is one of the most deadly ailments known to mankind due to its high mortality rate(up to 90%) accompanying with the disease. Ebola haemorrhagic fever(EHF) is an infectious disease of animal that can be transmitted to both human and non-human primates. The first epidemic of EHF occurred in 1976 in the Democratic Republic of the Congo. The incubation period of ebola is less than 21 days. Ebola virus infections are depicted by immune suppression and a systemic inflammatory response that leads to damage of the vascular, coagulation and immune systems, causing multi-organ failure and shock. Five genetically distinct members of the Filoviridae family responsible for EHF are as follows: Zaire ebolavirus, Sudan ebolavirus, C?te d'Ivoire ebolavirus, Bundibugyo ebolavirus and Reston ebolavirus. The ongoing 2014 West Africa ebola epidemic has been considered as the most serious panic in the medical field with respect to both the number of human cases and death toll. The natural host for ebola virus is unknown, thus it is not possible to carry out programs to regulate or abolish virus from transmission to people. The ebola virus infection provides little chance to develop acquired immunity causing rapid progression of the disease. It is pertinent to mention that at present, there is no antiviral therapy or vaccine that is helpful against ebola virus infection in humans. The impediment of EHF necessitates much better understanding of the epidemiology of the disease, particularly the role of wildlife, as well as bats, in the spread of ebola virus to humans.

Nucleoprotein-based indirect enzyme-linked immunosorbent assay(indirect ELISA) for detecting antibodies specific to Ebola virus and Marbug virus

Full-length nucleoproteins from Ebola and Marburg viruses were expressed as His-tagged recombinant proteins in Escherichia coli and nucleoprotein-based enzyme-linked immunosorbent assays(ELISAs) were established for the detection of antibodies specific to Ebola and Marburg viruses. The ELISAs were evaluated by testing antisera collected from rabbit immunized with Ebola and Marburg virus nucleoproteins. Although little cross-reactivity of antibodies was observed in antiEbola virus nucleoprotein rabbit antisera, the highest reactions to immunoglobulin G(Ig G) were uniformly detected against the nucleoprotein antigens of homologous viruses. We further evaluated the ELISA's ability to detect antibodies to Ebola and Marburg viruses using human sera samples collected from individuals passing through the Guangdong port of entry. With a threshold set at the mean plus three standard deviations of average optical densities of sera tested, the ELISA systems using these two recombinant nucleoproteins have good sensitivity and specificity. These results demonstrate the usefulness of ELISA for diagnostics as well as ecological and serosurvey studies of Ebola and Marburg virus infection.

Ebola viral disease: a review literature

Ebola virus is transmitted to people as a result of direct contact with body fluids containing virus of an infected patient. The incubation period usually lasts 5 to 7 d and approximately95% of the patients appear signs within 21 d after exposure. Typical features include fever,profound weakness, diarrhea, abdominal pain, cramping, nausea and vomiting for 3-5days and maybe persisting for up to a week. Laboratory complications including elevated aminotransferase levels, marked lymphocytopenia, and thrombocytopenia may have occurred.Hemorrhagic fever occurs in less than half of patients and it takes place most commonly in the gastrointestinal tract. The symptoms progress over the time and patients suffer from dehydration, stupor, confusion, hypotension, multi-organ failure, leading to fulminant shock and eventually death. The most general assays used for antibody detection are direct IgG and IgM ELISAs and IgM capture ELISA. An IgM or rising IgG titer(four-fold) contributes to strong presumptive diagnosis. Currently neither a licensed vaccine nor an approved treatment is available for human use. Passive transfer of serum collected from survivors of Junin virus or Lassa virus, equine IgG product from horses hypervaccinated with Ebola virus, a "cocktail"of humanized-mouse antibodies(ZMapp), recombinant inhibitor of factor VIIa/tissue factor,activated protein C, RNA-polymerase inhibitors and small interfering RNA nano particles are among the therapies in development. Preclinical evaluation is also underway for various vaccine candidates. One is a chimpanzee adenovirus vector vaccine; other vaccines involve replication-defective adenovirus serotype 5 and recombinant vesicular stomatitis virus.

Misinformation on salt water use among Nigerians during 2014 Ebola outbreak and the role of social media

Objective: To determine the spread of misinformation on salt water among Nigerians, salt water use for Ebola prophylaxis, and the role played by the social media during the 2014 Ebola outbreak.Methods: Information was collected from the general Nigerian population through online Google forms which were majorly disseminated via Facebook and WhatsApp platforms. The data retrieved was analysed using descriptive statistics, Chi-square test and multivariate logistic regression.Results: A total of 703 questionnaires were included in the final analysis. The respondents' mean age was(30.2±6.7) years, predominantly male(73.2%). Almost all of them(95.0%) had received some message to use salt water, 37.4% of whom received such message on social media. Around a half of them ever made an attempt to verify the health information they received on social media(50.9%), and about a quarter(24.0%) of them had used salt water during the outbreak. Many of them had used salt water because they believed it would not harm them(52.0%). Salt water was less likely to be used by those who had received such message on social media, as well as by those who had received some contrary information to salt use.Conclusions: Social media could serve as an effective tool in propagating health information and should be actively engaged by health agencies, to spread accurate information.

Ebola virus disease: From epidemiology to prophylaxis

The outbreak of Ebola virus disease(EVD) continues to spread through West Africa. Since the first reported EVD in March 2014, the number of cases has increased rapidly, with the fatality rate of >50%. The most prevalent Ebola virus belongs to the species of Zaire ebolavirus, with a mortality rate as high as 90%. Although there were introduced cases in other continents, Africa is the endemic area where fruit bats and apes are suspected to be Ebola virus carriers. The virus might be transmitted from the host animals to humans if humans consume relative raw and contaminated meats; however, human-to-human transmission via close contact is the major route of current outbreaks. EVD happens at any seasons and affected people of any race in any age groups. Direct contact with body fluids of EVD patients and living in the contaminated environment greatly increase the risk of being infected. Transmission viaaerosol is less possible but the transmission via droplet is possible in humans. Thus, health care providers are facing danger of getting Ebola virus infection. So far, there are limited vaccines, drugs and/or therapies to prevent Ebola virus infection or treat EVD. Medical workers should follow the current standard prophylactic procedures. Military forces can orchestrate efficient care to mass EVD casualties. Although it is necessary to speed up the pace of developing effective vaccine and therapeutics for the prevention and treatment of EVD, public health prophylaxis is the most important issue at present to control the spread of this disease cost-effectively.

Social network analysis and modeling of cellphone-based syndromic surveillance data for ebola in Sierra Leone

Objective:To explore and visualize the connectivity of suspected Ebola cases and surveillance callers who used cellphone technology in Moyamba District in Sierra Leone for Ebola surveillance,and to examine the demographic differences and characteristics of Ebola surveillance callers who make more calls as well as those callers who are more likely to make at least one positive Ebola call.Methods:Surveillance data for 393 suspected Ebola cases(192 males,201 females) were collected from October 23,2014 to June 28,2015 using cellphone technology.UCINET and Net Draw software were used to explore and visualize the social connectivity between callers and suspected Ebola cases.Poisson and logistic regression analyses were used to do multivariable analysis.Results:The entire social network was comprised of 393 ties and 745 nodes.Women(AOR=0.33,95% CI [0.14,0.81]) were associated with decreased odds of making at least one positive Ebola surveillance call compared to men.Women(IR= 0.63,95% CI [0.49,0.82]) were also associated with making fewer Ebola surveillance calls compared to men.Conclusion:Social network visualization can analyze syndromic surveillance data for Ebola collected by cellphone technology with unique insights.

Ebola in West Africa:an international medical emergency

West Africa is facing the worst Ebola outbreak with 3685 cases and 1841 deaths reported from Liberia,Cuinea,Senegal,Sierra Leona and Nigeria.There is no vaccine or direct treatment available to treat the patients with Ebola.World Health Organization(WHO) has approved the use of experimental drugs for Ebola patients.Health workers are at high risk.The governments and WHO are responsible to provide necessary protective equipment to health workers dealing with Ebola.There is a strong need to identify the invisible chains of virus transmission.World Bank pledges $200 million to fight against Ebola,while WHO said $430 million are needed to control the Ebola outbreak.Ebola can be contained by early detection and isolation of case,contact tracing,monitoring of contacts and adaptation of rigorous procedures for virus control.

Neutralizing Antibody Titer Test of Ebola Recombinant Protein Vaccine and Gene Vector Vaccine pVR-GP-FC

Objective In previous studies, we immunized mice with Ebola recombinant protein vaccine and gene vector vaccine. Both stimulated high levels of humoral immunity. In this work, we constructed a pseudovirus containing Ebola membrane proteins to verify whether the two immunization strategies can induce neutralizing antibodies in mice. Methods A pseudovirus containing an Ebola virus membrane protein based on the HIV-1 viral gene sequence was constructed and evaluated using a known neutralizing antibody. The titer of the neutralizing antibody in the sera of mice immunized with the recombinant protein and the gene vector vaccine was examined using a neutralization test. Results Ebola pseudovirus was successfully prepared and applied for neutralizing antibody detection. Immunological experiments showed that recombinant protein GP-Fc and gene vaccine pVR-modGP-Fc had good immunogenicity. The titer of the bound antibody in the serum after 8 weeks of immunization in mice was more than 1：105, and the recombinant protein induced greater humoral immunity. The results of the neutralization test based on the Ebola pseudovirus system demonstrated that both vaccines induced production of protective antibodies, while the gene vaccine induced a higher titer of neutralizing antibodies. Conclusion An Ebola pseudovirus detection system was successfully established and used to evaluate two Ebola vaccines. Both produced good immunogenicity. The findings lay the foundation for the development of new Ebola vaccines and screening for neutralizing monoclonal antibodies.

Ebola vaccine 2014:remained problems to be answered

Ebola virus outbreak in Africa in 2014 is a big global issue.The vaccine is the hope for management of the present outbreak of Ebola virus infection.There are several ongoing researches on new Ebola vaccine.In this short manuscript,we discuss and put forward specific remained problems to be answered on this specific issue.Lack for complete knowledge on the new emerging virus,concern from pharmaceutical company and good trial of new vaccine candidates are the remained problem to be further discussed in vaccinology.

Detection and Analysis of Ebola Virus in Sierra Leone-China Friendship Biosafety Laboratory from March 11 to April 20, 2015

Ebola virus disease reemerged in Western Africa in 2014.Chinese Center for Disease Control and Prevention dispatched the first Ebola virus（EBOV）detection team to run newly established Sierra Leone-China Friendship Biological Safety Laboratory.The aims of study were to understand epidemiology,clinical manifestations and survival time of EBOV in patient＇s blood.A total of 913specimens were tested between March 11 and April20, 2015. EBOV positivity occurred in 7.37% of the blood and 0.53% in throat swabs.

Ebola virus disease: Recent advances in diagnostics and therapeutics

Ebola virus disease(EVD)is associated with haemorrhagic fever in humans and nonhuman primates,with a high rate of fatality(up to 90%).Some outbreaks in human history have proven the lethality of EVD.The recent epidemic of 2014 and 2015 in West Africa was the deadliest of all time(11 284 deaths).To understand the transmission dynamics,we have reviewed the epidemiology of EVD to date.The absence of any licensed vaccines or approved drugs against Ebola virus(EBOV)further highlights the severity and crisis level of EVD.Some organizations(public and private)are making considerable efforts to develop novel therapeutic approaches or vaccines to contain the outbreak of EBOV shortly.Here,we summarized the various potential drugs and vaccines(undergoing multiple phases of clinical trials)that have arisen as an alternative against EBOV,and we highlighted the numerous issues and limitations hindering this process.Alternatively,an increasing focus on strengthening the medical and civic health structure could provide speedy benefits in containing the spread of EVD,as well as offer a resilient foundation for the deployment of novel drugs and vaccines to the affected countries,once such drugs and vaccines become available.

Key features of Ebola hemorrhagic fever:a review

The current outbreak of Ebola virus in West Africa has become a devastating problem.with a mortality rate around 51%;over 3132 deaths have been confirmed and even more arc expected in this case.The virus causes a characteristic disease known as hemorrhagic fever.Its symptoms range from nonspecific signs such as fever,lo more specific problems such as serious bleeding.Transmission occurs easily when a person comes in contact with contaminated fluids.Treatment is supportive because there are still no specific drugs for use.The present review focuses on the main features related to the Ebola virus,its transmission,pathogenesis,treatment and control forms.There is little in-depth knowledge about this disease,but its severily requires attention and information lo prevent a worse scenario than the current.

Optimal control application to an Ebola model

Ebola virus is a severe,frequently fatal illness,with a case fatality rate up to 90%.The outbreak of the disease has been acknowledged by World Health Organization as Public Health Emergency of International Concern.The threat of Ebola in West Africa is still a major setback to the socioeconomic development.Optimal control theory is applied to a system of ordinary differential equations which is modeling Ebola infection through three different routes including contact between humans and a dead body.In an attempt to reduce infection in susceptible population,a preventive control is put in the form of education and campaign and two treatment controls are applied to infected and late-stage infected(super) human population.The Pontryagins maximum principle is employed to characterize optimality control,which is then solved numerically.It is observed that time optimal control is existed in the model.The activation of each control showed a positive reduction of infection.The overall effect of activation of all the controls simultaneously reduced the effort required for the reduction of the infection quickly.The obtained results present a good framework for planning and designing cost-effective strategies for good interventions in dealing with Ebola disease.It is established that in order to reduce Ebola threat all the three controls must be taken into consideration concurrently.