Spatial-temporal transmission dynamics and control of infectious diseases: Ebola virus disease (EVD) as a case study

Author(s):  
Cécile Viboud ◽  
Hélène Broutin ◽  
Gerardo Chowell

Disentangling the spatial-temporal dynamics of infectious disease transmission is important to address issues of disease persistence, epidemic growth and optimal control. In this chapter, we review key concepts relating to the spatial-temporal dynamics of infectious diseases in meta-populations, whereby geographically separate subpopulations are connected by migration or mobility rates. We review the dynamics of colonization, persistence and extinction of emerging and recurrent pathogens in meta-populations; the role of demographic and environmental factors; and geographic heterogeneity in epidemic growth rate. We illustrate theoretical concepts by reviewing the spatial dynamics of childhood diseases and other acute infections in low- and middle-income countries, and provide a detailed description of the spatial-temporal dynamics of the 2014–16 Ebola epidemic in West Africa. We further discuss how increased availability of empirical data and recent methodological developments provide a deeper mechanistic understanding of transmission processes in space and time, and make recommendations for future work.

2020 ◽  
Vol 18 (6) ◽  
pp. 81-89
Author(s):  
E. G. Yanovich ◽  
E. A. Moskvitina

Along with the theoretical concepts and definitions of risk adopted in the epidemiological analysis of infectious diseases, the identification of «risk areas» is of great importance.The aim is to show the role of risk factors when determining the «risk areas» and in the genesis of complications of the epidemiological situation. Taking into account the multifactorial nature of the epidemic process under infectious diseases, we describe the risks used in zoning of natural focal particularly dangerous (plague, tularemia, anthrax, Ebola virus disease, Yellow fever); arbovirus (Crimean-Congo haemorrhagic fever, West Nile Fever and anthroponotic (cholera and other acute enteric infection (AEI) of norovirus, rotavirus and enterovirus etiology) infections. The importance of risk factors and conditions for their implementation in AEI with water pathogen distribution (unsatisfactory state of water supply and water use, population migration, etc.) and emergencies, in which certain risk factors can contribute to the complication of the epidemic situation, is shown.Conclusion. The use of risk factors in zoning of administrative territories is aimed at improving epidemiological surveillance. It is possible that potential risk factors can transfer to real, what results in activation of the epidemic process.


2020 ◽  
Vol 3 (1) ◽  
pp. 43-57 ◽  
Author(s):  
Russel J Reiter ◽  
Qiang Ma ◽  
Ramaswamy Sharma

This review summarizes published reports on the utility of melatonin as a treatment for virus-mediated diseases. Of special note are the data related to the role of melatonin in influencing Ebola virus disease. This infection and deadly condition has no effective treatment and the published works documenting the ability of melatonin to attenuate the severity of viral infections generally and Ebola infection specifically are considered. The capacity of melatonin to prevent one of the major complications of an Ebola infection, i.e., the hemorrhagic shock syndrome, which often contributes to the high mortality rate, is noteworthy. Considering the high safety profile of melatonin, the fact that it is easily produced, inexpensive and can be self-administered makes it an attractive potential treatment for Ebola virus pathology.  


2016 ◽  
Vol 10 (05) ◽  
pp. 537-543 ◽  
Author(s):  
Giulia Bertoli ◽  
Marco Mannazzu ◽  
Giordano Madeddu ◽  
Riccardo Are ◽  
Alberto Muredda ◽  
...  

Since the onset of the worst epidemic of Ebola virus disease in December 2013, 28,637 cases were reported as confirmed, probable, or suspected. Since the week of 3 January 2016, no more cases have been reported. The total number of deaths have amounted to 11,315 (39.5%). In developed countries, seven cases have been diagnosed: four in the United States, one in Spain, one in the United Kingdom, and one in Italy. On 20 July 2015, Italy was declared Ebola-free. On 9 May 2015, an Italian health worker came back to Italy after a long stay in Sierra Leone working for a non-governmental organization. Forty-eight hours after his arrival, he noticed headache, weakness, muscle pains, and slight fever. The following day, he was safely transported to the Infectious Diseases Unit of University Hospital of Sassari. The patient was hospitalized for 19 hours until an Italian Air Force medical division transferred him to Rome, to the Lazzaro Spallanzani Institute. Nineteen people who had contacts with the patient were monitored daily for 21 days by the Public Health Office of Sassari and none presented any symptoms. So far, neither vaccine nor treatment is available to be proposed on an international scale. Ebola is considered a re-emerging infectious disease which, unlike in the past, has been a worldwide emergency. This case study aimed to establish a discussion about the operative and logistic difficulties to be faced and about the discrepancy arising when protocols clash with the reality of facts.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Eric Okyere ◽  
Johnson De-Graft Ankamah ◽  
Anthony Kodzo Hunkpe ◽  
Dorcas Mensah

In this paper, we have studied epidemiological models for Ebola infection using nonlinear ordinary differential equations and optimal control theory. We considered optimal control analysis of SIR and SEIR models for the deadly Ebola infection using vaccination, treatment, and educational campaign as time-dependent control functions. We have applied indirect methods to study existing deterministic optimal control epidemic models for Ebola virus disease. These methods in optimal control are based on Hamiltonian function and Pontryagin’s maximum principle to construct adjoint equations and optimality systems. The forward-backward sweep numerical scheme with the fourth-order Runge–Kutta method is used to solve the optimality system for the various control strategies. From our numerical illustrations, we can conclude that effective educational campaigns and vaccination of susceptible individuals as well as effective treatments of infected individuals can help reduce the disease transmission.


2018 ◽  
Vol 3 (2) ◽  
pp. e000534 ◽  
Author(s):  
Darryl Stellmach ◽  
Isabel Beshar ◽  
Juliet Bedford ◽  
Philipp du Cros ◽  
Beverley Stringer

Recent outbreaks of Ebola virus disease (2013–2016) and Zika virus (2015–2016) bring renewed recognition of the need to understand social pathways of disease transmission and barriers to care. Social scientists, anthropologists in particular, have been recognised as important players in disease outbreak response because of their ability to assess social, economic and political factors in local contexts. However, in emergency public health response, as with any interdisciplinary setting, different professions may disagree over methods, ethics and the nature of evidence itself. A disease outbreak is no place to begin to negotiate disciplinary differences. Given increasing demand for anthropologists to work alongside epidemiologists, clinicians and public health professionals in health crises, this paper gives a basic introduction to anthropological methods and seeks to bridge the gap in disciplinary expectations within emergencies. It asks: ‘What can anthropologists do in a public health crisis and how do they do it?’ It argues for an interdisciplinary conception of emergency and the recognition that social, psychological and institutional factors influence all aspects of care.


2021 ◽  
Vol 9 ◽  
Author(s):  
Patrice Debré ◽  
Marie Neunez ◽  
Michel Goldman

Ebola virus disease is one of the deadliest infections in the world today. The microbe to blame is the Ebola virus. It has already caused numerous outbreaks in Africa, in the regions located south of the Sahara. This article describes the main characteristics of this infectious disease as well as the currently available treatments, namely vaccines and antibodies. Antibodies are produced by the human body when it is infected by a microbe. Antibodies can be collected from the blood of infected humans or animals and purified or manufactured in a laboratory to produce drugs. While vaccines have demonstrated their effectiveness in preventing infectious diseases, antibodies are effective in stopping the progression of several infectious diseases. In this article, you will discover that the stimulation of the immune system, either by the vaccine or by antibodies, is essential to tackle Ebola virus disease.


Author(s):  
Stephen B. Kennedy ◽  
John B. Dogba ◽  
Christine L. Wasunna ◽  
Philip Sahr ◽  
Candace B. Eastman ◽  
...  

Prior to the Ebola virus disease outbreak in Liberia, the laboratory system was duplicativefragmented and minimally coordinated. The National Reference Laboratory was conceptualisedto address the existing challenges by promoting the implementation of effective and sustainablelaboratory services in Liberia. However, in a resource-limited environment such as Liberiaprogress regarding the rebuilding of the health system can be relatively slow, while efforts tosustain the transient gains remain a key challenge for the Ministry of Health. In this paper, wedescribe the pre-Ebola virus disease laboratory system in Liberia and its prevailing efforts toaddress future emerging infectious diseases, as well as current Infectious diseases, all of whichare exacerbated by poverty. We conclude that laboratory and diagnostic services in Liberiahave encountered numerous challenges regarding its efforts to strengthen the healthcaredelivery system. These challenges include limited trained human resource capacity, inadequateinfrastructure, and a lack of coordination. As with most countries in sub-Saharan Africa, whencomparing urban and rural settings, diagnostic and clinical services are generally skewedtoward urban health facilities and private, faith-based health facilities. We recommend thatstructured policy be directed at these challenges for national institutions to develop guidelinesto improve, strengthen and sustain diagnostic and curative laboratory services to effectivelyaddress current infectious diseases and prepare for future emerging and re-emerging infectiousdiseases.


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