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 epidemi...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.展开更多
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 prev...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.展开更多
Background:By 28 June 2015,there were a total of 11,234 deaths from the Ebola virus disease(EVD)in five West African countries(Guinea,Liberia,Mali,Nigeria and Sierra Leone).The objective of this study was to estimate ...Background:By 28 June 2015,there were a total of 11,234 deaths from the Ebola virus disease(EVD)in five West African countries(Guinea,Liberia,Mali,Nigeria and Sierra Leone).The objective of this study was to estimate the future productivity losses associated with EVD deaths in these West African countries,in order to encourage increased investments in national health systems.Methods:A cost-of-illness method was employed to calculate future non-health(NH)gross domestic product(GDP)(NHGDP)losses associated with EVD deaths.The future non-health GDP loss(NHGDPLoss)was discounted at 3%.Separate analyses were done for three different age groups(<=14 years,15–44 years and=>45 years)for the five countries(Guinea,Liberia,Mali,Nigeria,and Sierra Leone)affected by EVD.We also conducted a one-way sensitivity analysis at 5 and 10%discount rates to gauge their impacts on expected NHGDPLoss.Results:The discounted value of future NHGDPLoss due to the 11,234 deaths associated with EVD was estimated to be Int$(international dollars)155,663,244.About 27.86%of the loss would be borne by Guinea,34.84%by Liberia,0.10%by Mali,0.24%by Nigeria and 36.96%by Sierra Leone.About 27.27%of the loss is attributed to those aged under 14 years,66.27%to those aged 15–44 years and 6.46%to those aged over 45 years.The average NHGDPLoss per EVD death was estimated to be Int$17,473 for Guinea,Int$11,283 for Liberia,Int$25,126 for Mali,Int$47,364 for Nigeria and Int$14,633 for Sierra Leone.Conclusion:In spite of alluded limitations,the estimates of human and economic losses reported in this paper,in addition to those projected by the World Bank,show that EVD imposes a significant economic burden on the affected West African countries.That heavy burden,coupled with human rights and global security concerns,underscores the urgent need for increased domestic and external investments to enable Guinea,Liberia and Sierra Leone(and other vulnerable African countries)to develop resilient health systems,including core capacities to detect,assess,notify,verify and report events,and to respond to public health risks and emergencies.展开更多
Public involvement in Ebola Virus Disease(EVD)prevention efforts is key to reducing disease outbreaks.Targeted education through practical health information to particular groups and sub-populations is crucial to cont...Public involvement in Ebola Virus Disease(EVD)prevention efforts is key to reducing disease outbreaks.Targeted education through practical health information to particular groups and sub-populations is crucial to controlling the disease.In this paper,we study the dynamics of Ebola virus disease in the presence of public health education with the aim of assessing the role of behavior change induced by health education to the dynamics of an outbreak.The power of behavior change is evident in two outbreaks of EVD that took place in Sudan only 3 years apart.The first occurrence was the first documented outbreak of EVD and produced a significant number of infections.The second outbreak produced far fewer cases,presumably because the population in the region learned from the first outbreak.We derive a system of ordinary differential equations to model these two contrasting behaviors.Since the population in Sudan learned from the first outbreak of EVD and changed their behavior prior to the second outbreak,we use data from these two instances of EVD to estimate parameters relevant to two contrasting behaviors.We then simulate a future outbreak of EVD in Sudan using our model that contains two susceptible populations,one being more informed about EVD.Our finding show how a more educated population results in fewer cases of EVD and highlights the importance of ongoing public health education.展开更多
The quarantine of people suspected of being exposed to an infectious agent is one of the most basic public health measure that has historically been used to combat the spread of communicable diseases in human communit...The quarantine of people suspected of being exposed to an infectious agent is one of the most basic public health measure that has historically been used to combat the spread of communicable diseases in human communities.This study presents a new deterministic model for assessing the population-level impact of the quarantine of individuals suspected of being exposed to disease on the spread of the 2014e2015 outbreaks of Ebola viral disease.It is assumed that quarantine is imperfect(i.e.,individuals can acquire infection during quarantine).In the absence of quarantine,the model is shown to exhibit global dynamics with respect to the disease-free and its unique endemic equilibrium when a certain epidemiological threshold(denoted byR 0)is either less than or greater than unity.Thus,unlike the full model with imperfect quarantine(which is known to exhibit the phenomenon of backward bifurcation),the version of the model with no quarantine does not undergo a backward bifurcation.Using data relevant to the 2014e2015 Ebola transmission dynamics in the three West African countries(Guinea,Liberia and Sierra Leone),uncertainty analysis of the model show that,although the current level and effectiveness of quarantine can lead to significant reduction in disease burden,they fail to bring the associated quarantine reproduction number(R Q0)to a value less than unity(which is needed to make effective disease control or elimination feasible).This reduction of R Q0 is,however,very possible with a modest increase in quarantine rate and effectiveness.It is further shown,via sensitivity analysis,that the parameters related to the effectiveness of quarantine(namely the parameter associated with the reduction in infectiousness of infected quarantined individuals and the contact rate during quarantine)are the main drivers of the disease transmission dynamics.Overall,this study shows that the singular implementation of a quarantine intervention strategy can lead to the effective control or elimination of Ebola viral disease in a community if its coverage and effectiveness levels are high enough.展开更多
Background: From May 2018 to September 2022, the Democratic Republic of Congo (DRC) experienced seven Ebola virus disease (EVD) outbreaks within its borders. During the 10th EVD outbreak (2018–2020), the largest expe...Background: From May 2018 to September 2022, the Democratic Republic of Congo (DRC) experienced seven Ebola virus disease (EVD) outbreaks within its borders. During the 10th EVD outbreak (2018–2020), the largest experienced in the DRC and the second largest and most prolonged EVD outbreak recorded globally, a WHO risk assessment identified nine countries bordering the DRC as moderate to high risk from cross border importation. These countries implemented varying levels of Ebola virus disease preparedness interventions. This case study highlights the gains and shortfalls with the Ebola virus disease preparedness interventions within the various contexts of these countries against the background of a renewed and growing commitment for global epidemic preparedness highlighted during recent World Health Assembly events.Main text: Several positive impacts from preparedness support to countries bordering the affected provinces in the DRC were identified, including development of sustained capacities which were leveraged upon to respond to the subsequent coronavirus disease 2019 (COVID-19) pandemic. Shortfalls such as lost opportunities for operationalizing cross-border regional preparedness collaboration and better integration of multidisciplinary perspectives, vertical approaches to response pillars such as surveillance, over dependence on external support and duplication of efforts especially in areas of capacity building were also identified. A recurrent theme that emerged from this case study is the propensity towards implementing short-term interventions during active Ebola virus disease outbreaks for preparedness rather than sustainable investment into strengthening systems for improved health security in alignment with IHR obligations, the Sustainable Development Goals and advocating global policy for addressing the larger structural determinants underscoring these outbreaks.Conclusions: Despite several international frameworks established at the global level for emergency preparedness, a shortfall exists between global policy and practice in countries at high risk of cross border transmission from persistent Ebola virus disease outbreaks in the Democratic Republic of Congo. With renewed global health commitment for country emergency preparedness resulting from the COVID-19 pandemic and cumulating in a resolution for a pandemic preparedness treaty, the time to review and address these gaps and provide recommendations for more sustainable and integrative approaches to emergency preparedness towards achieving global health security is now.展开更多
Recent 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 a...Recent 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.展开更多
Background:Following the West Africa Ebola virus disease(EVD)outbreak(2013-2016),WHO developed a preparedness checklist for its member states.This checklist is currently being applied for the first time on a large and...Background:Following the West Africa Ebola virus disease(EVD)outbreak(2013-2016),WHO developed a preparedness checklist for its member states.This checklist is currently being applied for the first time on a large and systematic scale to prepare for the cross border importation of the ongoing EVD outbreak in the Democratic Republic of Congo hence the need to document the lessons learnt from this experience.This is more pertinent considering the complex humanitarian context and weak health system under which some of the countries such as the Republic of South Sudan are implementing their EVD preparedness interventions.Main text:We identified four main lessons from the ongoing EVD preparedness efforts in the Republic South Sudan.First,EVD preparedness is possible in complex humanitarian settings such as the Republic of South Sudan by using a longer-term health system strengthening approach.Second,the Republic of South Sudan is at risk of both domestic and cross border transmission of EVD and several other infectious disease outbreaks hence the need for an integrated and sustainable approach to outbreak preparedness in the country.Third,a phased and well-prioritized approach is required for EVD preparedness in complex humanitarian settings given the costs associated with preparedness and the difficulties in the accurate prediction of outbreaks in such settings.Fourth,EVD preparedness in complex humanitarian settings is a massive undertaking that requires effective and decentralized coordination.Conclusion:Despite a very challenging context,the Republic of South Sudan made significant progress in its EVD preparedness drive demonstrating that it is possible to rapidly scale up preparedness efforts in complex humanitarian contexts if appropriate and context-specific approaches are used.Further research,systematic reviews and evaluation of the ongoing preparedness efforts are required to ensure comprehensive documentation and application of the lessons learnt for future EVD outbreak preparedness and response efforts.展开更多
Background:Clinical and laboratory data were collected and analysed from patients with Ebola virus disease(EVD)in Jui Government Hospital in Freetown,Sierra Leone,where patients with EVD were received and/or treated f...Background:Clinical and laboratory data were collected and analysed from patients with Ebola virus disease(EVD)in Jui Government Hospital in Freetown,Sierra Leone,where patients with EVD were received and/or treated from October 1,2014 to March 21,2015 during the West Africa EVD outbreak.Methods:The study admitted 285 patients with confirmed EVD and followed them up till the endpoint(recovery or death).EVD was confirmed by quantitative RT-PCR assays detecting blood Ebola virus(EBOV).Results:Among the 285 lab-confirmed EVD cases in Jui Government Hospital,146 recovered and 139 died,with an overall survival rate of 51.23%.Patients under the age of 6 years had a lower survival rate(37.50%).Most non-survivors(79.86%)died within 7 days after admission and the mean hospitalization time for non-survivors was 5.56±6.11 days.More than half survivors(63.69%)turned blood EBOV negative within 3 weeks after admission and the mean hospitalization time for survivors was 20.38±7.58 days.High blood viral load(≥106 copies/ml)was found to be predictive of the non-survival outcome as indicated by the Receiver Operating Characteristic(ROC)curve analysis.The probability of patients’survival was less than 15%when blood viral load was greater than 106 copies/ml.Multivariate analyses showed that blood viral load(P=0.005),confusion(P=0.010),abdominal pain(P=0.003),conjunctivitis(P=0.035),and vomiting(P=0.004)were factors independently associated with the outcomes of EVD patients.Conclusions:Most death occurred within 1 week after admission,and patients at the age of 6 or younger had a lower survival rate.Most surviving patients turned blood EBOV negative within 1–4 weeks after admission.Factors such as high blood viral load,confusion,abdominal pain,vomiting and conjunctivitis were associated with poor prognosis for EVD patients.展开更多
Ebola virus disease(EVD)is a life-threatening viral disease with a fatality rate ranging from around 30%to 90%.The first EVD outbreak was reported in the 1970s in Zaire(now the Democratic Republic of the Congo).Until ...Ebola virus disease(EVD)is a life-threatening viral disease with a fatality rate ranging from around 30%to 90%.The first EVD outbreak was reported in the 1970s in Zaire(now the Democratic Republic of the Congo).Until 2013,most outbreaks occurred in the Central Africa region,including Zaire,Sudan and Uganda.However,between March and October 2014,over 10000 cases of EVD have been recorded in West Africa,such as in Guinea,Liberia,Sierra Leone,and Nigeria,and a few hospital or secondary infections of EVD have occurred in Spain and the United States of America.EVD is presently one of the world's most feared diseases.In this literature review,we describe the epidemiology,clinical features,diagnosis,and treatment of EVD.展开更多
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...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.展开更多
The family Filoviridae, which includes the genera Marburgvirus and Ebolavirus, contains some of the most pathogenic viruses in humans and non-human primates(NHPs), causing severe hemorrhagic fevers with high fatality ...The family Filoviridae, which includes the genera Marburgvirus and Ebolavirus, contains some of the most pathogenic viruses in humans and non-human primates(NHPs), causing severe hemorrhagic fevers with high fatality rates. Small animal models against filoviruses using mice, guinea pigs, hamsters, and ferrets have been developed with the goal of screening candidate vaccines and antivirals, before testing in the gold standard NHP models. In this review, we summarize the different animal models used to understand filovirus pathogenesis, and discuss the advantages and disadvantages of each model with respect to filovirus disease research.展开更多
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 Inter...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.展开更多
This paper examines the potential contribution of the fisheries sector to national economic development in Sierra Leone, following the cessation of the recent Ebola virus disease (EVD). The tragic deaths of some 4000 ...This paper examines the potential contribution of the fisheries sector to national economic development in Sierra Leone, following the cessation of the recent Ebola virus disease (EVD). The tragic deaths of some 4000 persons, as a direct result of this epidemic, have also been accompanied by serious economic disruption to one of the world’s poorest countries, amounting to a loss of over USD 1 billion (20 per cent of annual Gross Domestic Product, GDP). Based on recent work undertaken by the New Partnership for Africa’s Development (NEPAD), an assessment was made of the potential contribution of one of the country’s major natural resource sectors—fisheries—to future economic recovery. It was confirmed that the fish resources of Sierra Leone have an estimated capitalised economic value of USD 735 million, and could potentially make an increased contribution to GDP under suitable conditions, over and above the current estimated level of 10 per cent. However, our results also show that with an overall “readiness assessment” score of 41/100, the sector is unlikely to realise its full potential unless a number of specific areas are addressed (based on analysis valid up to January 2016). These include an improvement in fisheries economic assessment, the upgrading of the fisheries governance and management framework, and the establishment of a fisheries development strategy and implementation plan to channel future investments and interventions in an appropriate sequence. Particular attention should be given early on to an increase in the quality and capacity of both public and private sector organisations relevant to roles and functions within a general process of fisheries sector reform. Finally, the fisheries policy evaluation approach used here is novel. While it has been applied to Sierra Leone for the intrinsic interest of that case, this demonstration also shows that it could be applied elsewhere in the future when reviewing fisheries policy.展开更多
Background:In the three decades since the first reported case of Ebola virus,most known index cases have been consistently traced to the hunting of“bush meat”,and women have consistently recorded relatively high fat...Background:In the three decades since the first reported case of Ebola virus,most known index cases have been consistently traced to the hunting of“bush meat”,and women have consistently recorded relatively high fatality rates in most catastrophic outbreaks.This paper discusses Ebola-related risk factors,which constantly interact with cultural values,and provides an insight into the link between gender and the risk of contracting infectious diseases,using Ebola virus as an example within Africa.Method:A comprehensive search of the literature was conducted using the PubMed,Ovid Medline and Global Health CABI databases as well as CAB Abstracts,including gray literature.We used a descriptive and sex-and gender-based analysis to revisit previous studies on Ebola outbreaks since 1976 to 2014,and disaggregated the cases and fatality rates according to gender and the sources of known index cases based on available data.Results:In total,approximately 1530 people died in all previous Ebola outbreaks from 1976 to 2012 compared with over 11,310 deaths from the 2014 outbreak.Women’s increased exposure can be attributed to time spent at home and their responsibility for caring for the sick,while men’s increased vulnerability to the virus can be attributed to their responsibility for caring for livestock and to time spent away from home,as most known sources of the index cases have been infected in the process of hunting.We present a conceptual model of a circle of interacting risk factors for Ebola in the African context.Conclusion:There is currently no evidence related to biological differences in female or male sex that increases Ebola virus transmission and vulnerability;rather,there are differences in the level of exposure between men and women.Gender is therefore an important risk factor to consider in the design of health programs.Building the capacity for effective risk communication is a worthwhile investment in public and global health for future emergency responses.展开更多
Background:The 2014 Ebola epidemic is the largest in history,affecting multiple countries in West Africa.Some isolated cases were also observed in other regions of the world.Method:In this paper,we introduce a determi...Background:The 2014 Ebola epidemic is the largest in history,affecting multiple countries in West Africa.Some isolated cases were also observed in other regions of the world.Method:In this paper,we introduce a deterministic SEIR type model with additional hospitalization,quarantine and vaccination components in order to understand the disease dynamics.Optimal control strategies,both in the case of hospitalization(with and without quarantine)and vaccination are used to predict the possible future outcome in terms of resource utilization for disease control and the effectiveness of vaccination on sick populations.Further,with the help of uncertainty and sensitivity analysis we also have identified the most sensitive parameters which effectively contribute to change the disease dynamics.We have performed mathematical analysis with numerical simulations and optimal control strategies on Ebola virus models.Results:We used dynamical system tools with numerical simulations and optimal control strategies on our Ebola virus models.The original model,which allowed transmission of Ebola virus via human contact,was extended to include imperfect vaccination and quarantine.After the qualitative analysis of all three forms of Ebola model,numerical techniques,using MATLAB as a platform,were formulated and analyzed in detail.Our simulation results support the claims made in the qualitative section.Conclusion:Our model incorporates an important component of individuals with high risk level with exposure to disease,such as front line health care workers,family members of EVD patients and Individuals involved in burial of deceased EVD patients,rather than the general population in the affected areas.Our analysis suggests that in order for R0(i.e.,the basic reproduction number)to be less than one,which is the basic requirement for the disease elimination,the transmission rate of isolated individuals should be less than one-fourth of that for non-isolated ones.Our analysis also predicts,we need high levels of medication and hospitalization at the beginning of an epidemic.Further,optimal control analysis of the model suggests the control strategies that may be adopted by public health authorities in order to reduce the impact of epidemics like Ebola.展开更多
Background:China has emerged as a powerful platform for global pharmaceutical research and development(R&D)amid the 2014 Ebola outbreak.The research and development impact of developing countries on prevention and...Background:China has emerged as a powerful platform for global pharmaceutical research and development(R&D)amid the 2014 Ebola outbreak.The research and development impact of developing countries on prevention and control of infectious disease outbreaks has long been underestimated,particularly for emerging economies like China.Here,we studied its research and development progress and government support in response to Ebola outbreak by timeline,input,and output at each research and development stage.This study will contribute to a deeper understanding of the research and development gaps and challenges faced by China,as well as providing evidence-based suggestions on how to accelerate the drug development process to meet urgent needs during future outbreaks.Methods:Data were obtained from the National Nature Science Foundation of China database,PubMed database,Patent Search System of the State Intelleaual Property Office of China,National Medical Products Administration,national policy reports and literature between Jan 1st,2006 and Dec 31st,2017.An overview of research funding,research output pharmaceutical product patent,and product licensed was described and analyzed by Microsoft Excel.A descriptive analysis with a visualization of plotting charts and graphs was conducted by reporting the mean±standard deviation.Results:China has successfully completed the research and development of the Ebola Ad5-EBOV vaccine within 26 months,while the preparation and implementation of clinical trials took relative long time.The National Nature Science Foundation of China funded CNY 44.05 million(USD 6.27 million)for Ebola-related researches and committed strongly to the phase of basic research(87.8%).A proliferation of literature arose between 2014 and 2015,with a 1.7-fold increase in drug research and a 2.5-fold increase in diagnostic research within 1 year.Three years on from the Ebola outbreak,six Ebola-related produas in China were approved by the National Medical Products Administration.Conclusions:China has started to emphasize the importance of medical produa innovation as one of the solutions for tackling emerging infectious diseases.Continuing research on the development of regulatory and market incentives,as well as a multilateral collaboration mechanism that unifies cross-channel supports,would advance the process for China to enter global R&D market more effectively.展开更多
Background:Ebola virus disease has reemerged as a major public health crisis in Africa,with isolated cases also observed globally,during the current outbreak.Methods:To estimate the basic reproductive ratio R0,which i...Background:Ebola virus disease has reemerged as a major public health crisis in Africa,with isolated cases also observed globally,during the current outbreak.Methods:To estimate the basic reproductive ratio R0,which is a measure of the severity of the outbreak,we developed a SEIR(susceptible-exposed-infected-recovered)type deterministic model,and used data from the Centers for Disease Control and Prevention(CDC),for the Ebola outbreak in Liberia and Sierra Leone.Two different data sets are available:one with raw reported data and one with corrected data(as the CDC suspects under-reporting).Results:Using a deterministic ordinary differential equation transmission model for Ebola epidemic,the basic reproductive ratio R0 for Liberia resulted to be 1.757 and 1.9 for corrected and uncorrected case data,respectively.For Sierra Leone,R0 resulted to be 1.492 and 1.362 for corrected and uncorrected case data,respectively.In each of the two cases we considered,the estimate for the basic reproductive ratio was initially greater than unity leading to an epidemic outbreak.Conclusion:We obtained robust estimates for the value of R0 associated with the 2014 Ebola outbreak,and showed that there is close agreement between our estimates of R0.Analysis of our model also showed that effective isolation is required,with the contact rate in isolation less than one quarter of that for the infected non-isolated population,and that the fraction of high-risk individuals must be brought to less than 10%of the overall susceptible population,in order to bring the value of R0 to less than 1,and hence control the outbreak.展开更多
Background:Ebola virus disease has taken a toll on more than 8,000 lives in West Africa in 2014.The most affected countries are Guinea,Liberia,and Sierra Leone.The number of people infected by Ebola in Sierra Leone su...Background:Ebola virus disease has taken a toll on more than 8,000 lives in West Africa in 2014.The most affected countries are Guinea,Liberia,and Sierra Leone.The number of people infected by Ebola in Sierra Leone surpassed that of Liberia in the last month in this year and almost half of human cases are distributed in this country.Discussion:The ignorance on Ebola among people,including health workers at the early stage,plaid an important role in spread of Ebola virus disease.Subsequently,Ebola ravages urban settings for the first time and takes a huge toll on the lives.The government and international partners do make efforts to control the epidemic,however,lack of synergy make them lip service.Summary:The leading role of government in the response to the epidemic should be emphasized.Basic information of Ebola should be quickly spread among communities by health education programme and social mobilization should be a basic measure for Ebola control.展开更多
Background:The Ebola virus disease spread rapidly in West Africa in 2014,leading to the loss of thousands of lives.Community engagement was one of the key strategies to interrupt Ebola transmission,and practical commu...Background:The Ebola virus disease spread rapidly in West Africa in 2014,leading to the loss of thousands of lives.Community engagement was one of the key strategies to interrupt Ebola transmission,and practical community level measures needed to be explored in the field and tailored to the specific context of communities.Methods:First,community-level education on Ebola virus disease(EVD)prevention was launched for the community’s social mobilizers in six districts in Sierra Leone beginning in November 2014.Then,from January to May of 2015,in three pilot communities,local trained community members were organized to engage in implementation of EVD prevention and transmission interruption measures,by involving them in alert case report,contact tracing,and social mobilization.The epidemiological indicators of transmission interruption in three study communities were evaluated.Results:A total of 6016 community social mobilizers from 185 wards were trained by holding 279 workshops in the six districts,and EVD message reached an estimated 631680 residents.In three pilot communities,72 EVD alert cases were reported,with 70.8%of them detected by trained local community members,and 14 EVD cases were finally identified.Contact tracing detected 64.3%of EVD cases.The median duration of community infectivity for the cases was 1 day.The secondary attack rate was 4.2%,and no third generation of infection was triggered.No health worker was infected,and no unsafe burial and noncompliance to EVD control measures were recorded.The community-based measures were modeled to reduce 77 EVD cases,and the EVD-free goal was achieved four months earlier in study communities than whole country of Sierra Leone.Conclusions: The community-based strategy of social mobilization and community engagement was effective in casedetection and reducing the extent of Ebola transmission in a country with weak health system. The successfullypractical experience to reduce the risk of Ebola transmission in the community with poor resources would potentiallybe helpful for the global community to fight against the EVD and the other diseases in the future.展开更多
基金funded by the National Natural Science Foundation of China[Grant No.71934002,Grant No.72122001]。
文摘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.
基金supported by the General Logistics of PLA in China (Grant No. AWS11L009)
文摘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.
文摘Background:By 28 June 2015,there were a total of 11,234 deaths from the Ebola virus disease(EVD)in five West African countries(Guinea,Liberia,Mali,Nigeria and Sierra Leone).The objective of this study was to estimate the future productivity losses associated with EVD deaths in these West African countries,in order to encourage increased investments in national health systems.Methods:A cost-of-illness method was employed to calculate future non-health(NH)gross domestic product(GDP)(NHGDP)losses associated with EVD deaths.The future non-health GDP loss(NHGDPLoss)was discounted at 3%.Separate analyses were done for three different age groups(<=14 years,15–44 years and=>45 years)for the five countries(Guinea,Liberia,Mali,Nigeria,and Sierra Leone)affected by EVD.We also conducted a one-way sensitivity analysis at 5 and 10%discount rates to gauge their impacts on expected NHGDPLoss.Results:The discounted value of future NHGDPLoss due to the 11,234 deaths associated with EVD was estimated to be Int$(international dollars)155,663,244.About 27.86%of the loss would be borne by Guinea,34.84%by Liberia,0.10%by Mali,0.24%by Nigeria and 36.96%by Sierra Leone.About 27.27%of the loss is attributed to those aged under 14 years,66.27%to those aged 15–44 years and 6.46%to those aged over 45 years.The average NHGDPLoss per EVD death was estimated to be Int$17,473 for Guinea,Int$11,283 for Liberia,Int$25,126 for Mali,Int$47,364 for Nigeria and Int$14,633 for Sierra Leone.Conclusion:In spite of alluded limitations,the estimates of human and economic losses reported in this paper,in addition to those projected by the World Bank,show that EVD imposes a significant economic burden on the affected West African countries.That heavy burden,coupled with human rights and global security concerns,underscores the urgent need for increased domestic and external investments to enable Guinea,Liberia and Sierra Leone(and other vulnerable African countries)to develop resilient health systems,including core capacities to detect,assess,notify,verify and report events,and to respond to public health risks and emergencies.
基金This research was conducted as part of the Masamu Advanced Study Institute(MASI),which is funded by NSF grant number 1343651.
文摘Public involvement in Ebola Virus Disease(EVD)prevention efforts is key to reducing disease outbreaks.Targeted education through practical health information to particular groups and sub-populations is crucial to controlling the disease.In this paper,we study the dynamics of Ebola virus disease in the presence of public health education with the aim of assessing the role of behavior change induced by health education to the dynamics of an outbreak.The power of behavior change is evident in two outbreaks of EVD that took place in Sudan only 3 years apart.The first occurrence was the first documented outbreak of EVD and produced a significant number of infections.The second outbreak produced far fewer cases,presumably because the population in the region learned from the first outbreak.We derive a system of ordinary differential equations to model these two contrasting behaviors.Since the population in Sudan learned from the first outbreak of EVD and changed their behavior prior to the second outbreak,we use data from these two instances of EVD to estimate parameters relevant to two contrasting behaviors.We then simulate a future outbreak of EVD in Sudan using our model that contains two susceptible populations,one being more informed about EVD.Our finding show how a more educated population results in fewer cases of EVD and highlights the importance of ongoing public health education.
基金A.Dénes was supported by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences,by the project no.128363implemented with the support provided from the National Research,Development and Innovation Fund of Hungary,financed under the PD_18 funding scheme and by the project no.125628+1 种基金implemented with the support provided from the National Research,Development and Innovation Fund of Hungary,financed under the KH_17 funding scheme.A.Gumel acknowledges the support,in part,of the Simons Foundation(Award#585022)The authors are grateful to the two anonymous reviewers for their very insightful and constructive comments.
文摘The quarantine of people suspected of being exposed to an infectious agent is one of the most basic public health measure that has historically been used to combat the spread of communicable diseases in human communities.This study presents a new deterministic model for assessing the population-level impact of the quarantine of individuals suspected of being exposed to disease on the spread of the 2014e2015 outbreaks of Ebola viral disease.It is assumed that quarantine is imperfect(i.e.,individuals can acquire infection during quarantine).In the absence of quarantine,the model is shown to exhibit global dynamics with respect to the disease-free and its unique endemic equilibrium when a certain epidemiological threshold(denoted byR 0)is either less than or greater than unity.Thus,unlike the full model with imperfect quarantine(which is known to exhibit the phenomenon of backward bifurcation),the version of the model with no quarantine does not undergo a backward bifurcation.Using data relevant to the 2014e2015 Ebola transmission dynamics in the three West African countries(Guinea,Liberia and Sierra Leone),uncertainty analysis of the model show that,although the current level and effectiveness of quarantine can lead to significant reduction in disease burden,they fail to bring the associated quarantine reproduction number(R Q0)to a value less than unity(which is needed to make effective disease control or elimination feasible).This reduction of R Q0 is,however,very possible with a modest increase in quarantine rate and effectiveness.It is further shown,via sensitivity analysis,that the parameters related to the effectiveness of quarantine(namely the parameter associated with the reduction in infectiousness of infected quarantined individuals and the contact rate during quarantine)are the main drivers of the disease transmission dynamics.Overall,this study shows that the singular implementation of a quarantine intervention strategy can lead to the effective control or elimination of Ebola viral disease in a community if its coverage and effectiveness levels are high enough.
文摘Background: From May 2018 to September 2022, the Democratic Republic of Congo (DRC) experienced seven Ebola virus disease (EVD) outbreaks within its borders. During the 10th EVD outbreak (2018–2020), the largest experienced in the DRC and the second largest and most prolonged EVD outbreak recorded globally, a WHO risk assessment identified nine countries bordering the DRC as moderate to high risk from cross border importation. These countries implemented varying levels of Ebola virus disease preparedness interventions. This case study highlights the gains and shortfalls with the Ebola virus disease preparedness interventions within the various contexts of these countries against the background of a renewed and growing commitment for global epidemic preparedness highlighted during recent World Health Assembly events.Main text: Several positive impacts from preparedness support to countries bordering the affected provinces in the DRC were identified, including development of sustained capacities which were leveraged upon to respond to the subsequent coronavirus disease 2019 (COVID-19) pandemic. Shortfalls such as lost opportunities for operationalizing cross-border regional preparedness collaboration and better integration of multidisciplinary perspectives, vertical approaches to response pillars such as surveillance, over dependence on external support and duplication of efforts especially in areas of capacity building were also identified. A recurrent theme that emerged from this case study is the propensity towards implementing short-term interventions during active Ebola virus disease outbreaks for preparedness rather than sustainable investment into strengthening systems for improved health security in alignment with IHR obligations, the Sustainable Development Goals and advocating global policy for addressing the larger structural determinants underscoring these outbreaks.Conclusions: Despite several international frameworks established at the global level for emergency preparedness, a shortfall exists between global policy and practice in countries at high risk of cross border transmission from persistent Ebola virus disease outbreaks in the Democratic Republic of Congo. With renewed global health commitment for country emergency preparedness resulting from the COVID-19 pandemic and cumulating in a resolution for a pandemic preparedness treaty, the time to review and address these gaps and provide recommendations for more sustainable and integrative approaches to emergency preparedness towards achieving global health security is now.
文摘Recent 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.
文摘Background:Following the West Africa Ebola virus disease(EVD)outbreak(2013-2016),WHO developed a preparedness checklist for its member states.This checklist is currently being applied for the first time on a large and systematic scale to prepare for the cross border importation of the ongoing EVD outbreak in the Democratic Republic of Congo hence the need to document the lessons learnt from this experience.This is more pertinent considering the complex humanitarian context and weak health system under which some of the countries such as the Republic of South Sudan are implementing their EVD preparedness interventions.Main text:We identified four main lessons from the ongoing EVD preparedness efforts in the Republic South Sudan.First,EVD preparedness is possible in complex humanitarian settings such as the Republic of South Sudan by using a longer-term health system strengthening approach.Second,the Republic of South Sudan is at risk of both domestic and cross border transmission of EVD and several other infectious disease outbreaks hence the need for an integrated and sustainable approach to outbreak preparedness in the country.Third,a phased and well-prioritized approach is required for EVD preparedness in complex humanitarian settings given the costs associated with preparedness and the difficulties in the accurate prediction of outbreaks in such settings.Fourth,EVD preparedness in complex humanitarian settings is a massive undertaking that requires effective and decentralized coordination.Conclusion:Despite a very challenging context,the Republic of South Sudan made significant progress in its EVD preparedness drive demonstrating that it is possible to rapidly scale up preparedness efforts in complex humanitarian contexts if appropriate and context-specific approaches are used.Further research,systematic reviews and evaluation of the ongoing preparedness efforts are required to ensure comprehensive documentation and application of the lessons learnt for future EVD outbreak preparedness and response efforts.
文摘Background:Clinical and laboratory data were collected and analysed from patients with Ebola virus disease(EVD)in Jui Government Hospital in Freetown,Sierra Leone,where patients with EVD were received and/or treated from October 1,2014 to March 21,2015 during the West Africa EVD outbreak.Methods:The study admitted 285 patients with confirmed EVD and followed them up till the endpoint(recovery or death).EVD was confirmed by quantitative RT-PCR assays detecting blood Ebola virus(EBOV).Results:Among the 285 lab-confirmed EVD cases in Jui Government Hospital,146 recovered and 139 died,with an overall survival rate of 51.23%.Patients under the age of 6 years had a lower survival rate(37.50%).Most non-survivors(79.86%)died within 7 days after admission and the mean hospitalization time for non-survivors was 5.56±6.11 days.More than half survivors(63.69%)turned blood EBOV negative within 3 weeks after admission and the mean hospitalization time for survivors was 20.38±7.58 days.High blood viral load(≥106 copies/ml)was found to be predictive of the non-survival outcome as indicated by the Receiver Operating Characteristic(ROC)curve analysis.The probability of patients’survival was less than 15%when blood viral load was greater than 106 copies/ml.Multivariate analyses showed that blood viral load(P=0.005),confusion(P=0.010),abdominal pain(P=0.003),conjunctivitis(P=0.035),and vomiting(P=0.004)were factors independently associated with the outcomes of EVD patients.Conclusions:Most death occurred within 1 week after admission,and patients at the age of 6 or younger had a lower survival rate.Most surviving patients turned blood EBOV negative within 1–4 weeks after admission.Factors such as high blood viral load,confusion,abdominal pain,vomiting and conjunctivitis were associated with poor prognosis for EVD patients.
文摘Ebola virus disease(EVD)is a life-threatening viral disease with a fatality rate ranging from around 30%to 90%.The first EVD outbreak was reported in the 1970s in Zaire(now the Democratic Republic of the Congo).Until 2013,most outbreaks occurred in the Central Africa region,including Zaire,Sudan and Uganda.However,between March and October 2014,over 10000 cases of EVD have been recorded in West Africa,such as in Guinea,Liberia,Sierra Leone,and Nigeria,and a few hospital or secondary infections of EVD have occurred in Spain and the United States of America.EVD is presently one of the world's most feared diseases.In this literature review,we describe the epidemiology,clinical features,diagnosis,and treatment of EVD.
文摘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.
基金supported by the Public Health Agency of Canada(PHAC)partially supported by the NIH and CIHR grants to X.G.Qiu(U19 AI109762-1 and CIHR-IER-143487,respectively)+1 种基金the National Natural Science Foundation of China International Cooperation and Exchange Program(8161101193)National Science and Technology Major Project(2016ZX10004222)to G.Wong
文摘The family Filoviridae, which includes the genera Marburgvirus and Ebolavirus, contains some of the most pathogenic viruses in humans and non-human primates(NHPs), causing severe hemorrhagic fevers with high fatality rates. Small animal models against filoviruses using mice, guinea pigs, hamsters, and ferrets have been developed with the goal of screening candidate vaccines and antivirals, before testing in the gold standard NHP models. In this review, we summarize the different animal models used to understand filovirus pathogenesis, and discuss the advantages and disadvantages of each model with respect to filovirus disease research.
文摘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.
文摘This paper examines the potential contribution of the fisheries sector to national economic development in Sierra Leone, following the cessation of the recent Ebola virus disease (EVD). The tragic deaths of some 4000 persons, as a direct result of this epidemic, have also been accompanied by serious economic disruption to one of the world’s poorest countries, amounting to a loss of over USD 1 billion (20 per cent of annual Gross Domestic Product, GDP). Based on recent work undertaken by the New Partnership for Africa’s Development (NEPAD), an assessment was made of the potential contribution of one of the country’s major natural resource sectors—fisheries—to future economic recovery. It was confirmed that the fish resources of Sierra Leone have an estimated capitalised economic value of USD 735 million, and could potentially make an increased contribution to GDP under suitable conditions, over and above the current estimated level of 10 per cent. However, our results also show that with an overall “readiness assessment” score of 41/100, the sector is unlikely to realise its full potential unless a number of specific areas are addressed (based on analysis valid up to January 2016). These include an improvement in fisheries economic assessment, the upgrading of the fisheries governance and management framework, and the establishment of a fisheries development strategy and implementation plan to channel future investments and interventions in an appropriate sequence. Particular attention should be given early on to an increase in the quality and capacity of both public and private sector organisations relevant to roles and functions within a general process of fisheries sector reform. Finally, the fisheries policy evaluation approach used here is novel. While it has been applied to Sierra Leone for the intrinsic interest of that case, this demonstration also shows that it could be applied elsewhere in the future when reviewing fisheries policy.
文摘Background:In the three decades since the first reported case of Ebola virus,most known index cases have been consistently traced to the hunting of“bush meat”,and women have consistently recorded relatively high fatality rates in most catastrophic outbreaks.This paper discusses Ebola-related risk factors,which constantly interact with cultural values,and provides an insight into the link between gender and the risk of contracting infectious diseases,using Ebola virus as an example within Africa.Method:A comprehensive search of the literature was conducted using the PubMed,Ovid Medline and Global Health CABI databases as well as CAB Abstracts,including gray literature.We used a descriptive and sex-and gender-based analysis to revisit previous studies on Ebola outbreaks since 1976 to 2014,and disaggregated the cases and fatality rates according to gender and the sources of known index cases based on available data.Results:In total,approximately 1530 people died in all previous Ebola outbreaks from 1976 to 2012 compared with over 11,310 deaths from the 2014 outbreak.Women’s increased exposure can be attributed to time spent at home and their responsibility for caring for the sick,while men’s increased vulnerability to the virus can be attributed to their responsibility for caring for livestock and to time spent away from home,as most known sources of the index cases have been infected in the process of hunting.We present a conceptual model of a circle of interacting risk factors for Ebola in the African context.Conclusion:There is currently no evidence related to biological differences in female or male sex that increases Ebola virus transmission and vulnerability;rather,there are differences in the level of exposure between men and women.Gender is therefore an important risk factor to consider in the design of health programs.Building the capacity for effective risk communication is a worthwhile investment in public and global health for future emergency responses.
文摘Background:The 2014 Ebola epidemic is the largest in history,affecting multiple countries in West Africa.Some isolated cases were also observed in other regions of the world.Method:In this paper,we introduce a deterministic SEIR type model with additional hospitalization,quarantine and vaccination components in order to understand the disease dynamics.Optimal control strategies,both in the case of hospitalization(with and without quarantine)and vaccination are used to predict the possible future outcome in terms of resource utilization for disease control and the effectiveness of vaccination on sick populations.Further,with the help of uncertainty and sensitivity analysis we also have identified the most sensitive parameters which effectively contribute to change the disease dynamics.We have performed mathematical analysis with numerical simulations and optimal control strategies on Ebola virus models.Results:We used dynamical system tools with numerical simulations and optimal control strategies on our Ebola virus models.The original model,which allowed transmission of Ebola virus via human contact,was extended to include imperfect vaccination and quarantine.After the qualitative analysis of all three forms of Ebola model,numerical techniques,using MATLAB as a platform,were formulated and analyzed in detail.Our simulation results support the claims made in the qualitative section.Conclusion:Our model incorporates an important component of individuals with high risk level with exposure to disease,such as front line health care workers,family members of EVD patients and Individuals involved in burial of deceased EVD patients,rather than the general population in the affected areas.Our analysis suggests that in order for R0(i.e.,the basic reproduction number)to be less than one,which is the basic requirement for the disease elimination,the transmission rate of isolated individuals should be less than one-fourth of that for non-isolated ones.Our analysis also predicts,we need high levels of medication and hospitalization at the beginning of an epidemic.Further,optimal control analysis of the model suggests the control strategies that may be adopted by public health authorities in order to reduce the impact of epidemics like Ebola.
文摘Background:China has emerged as a powerful platform for global pharmaceutical research and development(R&D)amid the 2014 Ebola outbreak.The research and development impact of developing countries on prevention and control of infectious disease outbreaks has long been underestimated,particularly for emerging economies like China.Here,we studied its research and development progress and government support in response to Ebola outbreak by timeline,input,and output at each research and development stage.This study will contribute to a deeper understanding of the research and development gaps and challenges faced by China,as well as providing evidence-based suggestions on how to accelerate the drug development process to meet urgent needs during future outbreaks.Methods:Data were obtained from the National Nature Science Foundation of China database,PubMed database,Patent Search System of the State Intelleaual Property Office of China,National Medical Products Administration,national policy reports and literature between Jan 1st,2006 and Dec 31st,2017.An overview of research funding,research output pharmaceutical product patent,and product licensed was described and analyzed by Microsoft Excel.A descriptive analysis with a visualization of plotting charts and graphs was conducted by reporting the mean±standard deviation.Results:China has successfully completed the research and development of the Ebola Ad5-EBOV vaccine within 26 months,while the preparation and implementation of clinical trials took relative long time.The National Nature Science Foundation of China funded CNY 44.05 million(USD 6.27 million)for Ebola-related researches and committed strongly to the phase of basic research(87.8%).A proliferation of literature arose between 2014 and 2015,with a 1.7-fold increase in drug research and a 2.5-fold increase in diagnostic research within 1 year.Three years on from the Ebola outbreak,six Ebola-related produas in China were approved by the National Medical Products Administration.Conclusions:China has started to emphasize the importance of medical produa innovation as one of the solutions for tackling emerging infectious diseases.Continuing research on the development of regulatory and market incentives,as well as a multilateral collaboration mechanism that unifies cross-channel supports,would advance the process for China to enter global R&D market more effectively.
文摘Background:Ebola virus disease has reemerged as a major public health crisis in Africa,with isolated cases also observed globally,during the current outbreak.Methods:To estimate the basic reproductive ratio R0,which is a measure of the severity of the outbreak,we developed a SEIR(susceptible-exposed-infected-recovered)type deterministic model,and used data from the Centers for Disease Control and Prevention(CDC),for the Ebola outbreak in Liberia and Sierra Leone.Two different data sets are available:one with raw reported data and one with corrected data(as the CDC suspects under-reporting).Results:Using a deterministic ordinary differential equation transmission model for Ebola epidemic,the basic reproductive ratio R0 for Liberia resulted to be 1.757 and 1.9 for corrected and uncorrected case data,respectively.For Sierra Leone,R0 resulted to be 1.492 and 1.362 for corrected and uncorrected case data,respectively.In each of the two cases we considered,the estimate for the basic reproductive ratio was initially greater than unity leading to an epidemic outbreak.Conclusion:We obtained robust estimates for the value of R0 associated with the 2014 Ebola outbreak,and showed that there is close agreement between our estimates of R0.Analysis of our model also showed that effective isolation is required,with the contact rate in isolation less than one quarter of that for the infected non-isolated population,and that the fraction of high-risk individuals must be brought to less than 10%of the overall susceptible population,in order to bring the value of R0 to less than 1,and hence control the outbreak.
文摘Background:Ebola virus disease has taken a toll on more than 8,000 lives in West Africa in 2014.The most affected countries are Guinea,Liberia,and Sierra Leone.The number of people infected by Ebola in Sierra Leone surpassed that of Liberia in the last month in this year and almost half of human cases are distributed in this country.Discussion:The ignorance on Ebola among people,including health workers at the early stage,plaid an important role in spread of Ebola virus disease.Subsequently,Ebola ravages urban settings for the first time and takes a huge toll on the lives.The government and international partners do make efforts to control the epidemic,however,lack of synergy make them lip service.Summary:The leading role of government in the response to the epidemic should be emphasized.Basic information of Ebola should be quickly spread among communities by health education programme and social mobilization should be a basic measure for Ebola control.
基金National Health and Family Planning Commission,and Ministry of Commerce,China.
文摘Background:The Ebola virus disease spread rapidly in West Africa in 2014,leading to the loss of thousands of lives.Community engagement was one of the key strategies to interrupt Ebola transmission,and practical community level measures needed to be explored in the field and tailored to the specific context of communities.Methods:First,community-level education on Ebola virus disease(EVD)prevention was launched for the community’s social mobilizers in six districts in Sierra Leone beginning in November 2014.Then,from January to May of 2015,in three pilot communities,local trained community members were organized to engage in implementation of EVD prevention and transmission interruption measures,by involving them in alert case report,contact tracing,and social mobilization.The epidemiological indicators of transmission interruption in three study communities were evaluated.Results:A total of 6016 community social mobilizers from 185 wards were trained by holding 279 workshops in the six districts,and EVD message reached an estimated 631680 residents.In three pilot communities,72 EVD alert cases were reported,with 70.8%of them detected by trained local community members,and 14 EVD cases were finally identified.Contact tracing detected 64.3%of EVD cases.The median duration of community infectivity for the cases was 1 day.The secondary attack rate was 4.2%,and no third generation of infection was triggered.No health worker was infected,and no unsafe burial and noncompliance to EVD control measures were recorded.The community-based measures were modeled to reduce 77 EVD cases,and the EVD-free goal was achieved four months earlier in study communities than whole country of Sierra Leone.Conclusions: The community-based strategy of social mobilization and community engagement was effective in casedetection and reducing the extent of Ebola transmission in a country with weak health system. The successfullypractical experience to reduce the risk of Ebola transmission in the community with poor resources would potentiallybe helpful for the global community to fight against the EVD and the other diseases in the future.
