EBOLA RESEARCH PAPER | Augustine Akharumere - sexygf.info
The motive is to establish the relationship between the determinants of Ebola Conceptual Framework of Ebola Virus Outbreak The earliest described to occur after an Ebola virus is transmitted to an initial human by contact with an. health response to the international spread of disease, in ways that Figure 1 depicts the conceptual framework of these fac- tors. Human Development Index .. or inverse relationship between indicator value and risk, in contrast to the. In this study, a systematic analysis of the spread during the months of March to The incubation period for Ebola virus in humans is between two to .. The concept of social networks has been successfully applied in various . into the model, although details on individual cases can at times be limited.
However, after recovery, a person can potentially remain infectious as long as their blood and body fluids, including semen and breast milk, contain the virus. In particular, men can potentially transmit the virus through their seminal fluid, within the first 7 to 12 weeks after recovery from EVD [ 2 ]. Table 1 shows the estimated time frames and projected progression of the infection in an average EVD patient.
A possible progression path of symptoms from exposure to the Ebola Virus to treatment or death. Table shows a suggested transition and time frame in humans, of the virus, from exposure to incubation to symptoms development and recovery or death.
This table is adapted based on the image in the Huffington post, via [ 11 ].
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Institutions and governments need to educate the public and raise awareness about risk factors, proper hand washing, proper handling of Ebola patients, quick reporting of suspected Ebola cases, safe burial practices, use of public transportation, and so forth.
From a global perspective, a good surveillance and contact tracing program followed by isolation and monitoring of probable and suspected cases, with immediate commencement of disease management for patients exhibiting symptoms of EVD, is important if we must, in the future, elude a global epidemic and control of EVD transmission locally and globally [ 2 ].
It was by effective surveillance, contact tracing, and isolation and monitoring of probable and suspected cases followed by immediate supportive care for individuals and families exhibiting symptoms that the EVD was brought under control in Nigeria [ 17 ], Senegal, USA, and Spain [ 1 ].
Efficient control and management of any future EVD outbreaks can be achieved if new, more economical, and realizable methods are used to target and manage the dynamics of spread as well as the population sizes of those communities that may be exposed to any future Ebola Virus Disease outbreak.
More realistic mathematical models can play a role in this regard, since analyses of such models can produce clear insight to vulnerable spots on the Ebola transmission chain where control efforts can be concentrated.
Good models could also help in the identification of disease parameters that can possibly influence the size of the reproduction number of EVD. Existing mathematical models for Ebola [ 141618 — 21 ] have been very instrumental in providing mathematical insight into the dynamics of Ebola Virus transmission. Many of these models have also been helpful in that they have provided methods to derive estimates for the reproduction number for Ebola based on data from the previous outbreaks. However, few of the models have taken into account the fact that institution of quarantine states or treatment centres will affect the course of the epidemic in the population [ 16 ].
It is our understanding that the way the disease will spread will be determined by the initial and continual response of the health services in the event of the discovery of an Ebola disease case.
The objective of this paper is to derive a comprehensive mathematical model for the dynamics of Ebola transmission taking into consideration what is currently known of the disease. The primary objective is to derive a formula for the reproduction number for Ebola Virus Disease transmission in view of providing a more complete and measurable index for the spread of Ebola and to investigate the level of impact of surveillance, contact tracing, isolation, and monitoring of suspected cases, in curbing disease transmission.
The model is formulated in a way that it is extendable, with appropriate modifications, to other disease outbreaks with similar characteristics to Ebola, requiring such contact tracing strategies. Our model differs from other mathematical models that have been used to study the Ebola disease [ 14151820 — 22 ] in that it captures the quarantined Ebola Virus Disease patients and provides possibilities for those who escaped quarantine at the onset of the disease to enter quarantine at later stages.
To the best of our knowledge, this is the first integrated ordinary differential equation model for this kind of communicable disease of humans. Our final result would be a formula for the basic reproduction number of Ebola that depends on the disease parameters. The rest of the paper is divided up as follows. In Section 2we outline the derivation of the model showing the state variables and parameters used and how they relate together in a conceptual framework.
In Section 3we present a mathematical analysis of the derived model to ascertain that the results are physically realizable.
The Ebola contagion and forecasting virus: evidence from four African countries
We then reparameterise the model and investigate the existence and linear stability of steady state solution, calculate the basic reproduction number, and present some special cases. In Section 4we present a discussion on the parameters of the model.
In Section 5we carry out some numerical simulations based on the selected feasible parameters for the system and then round up the paper with a discussion and conclusion in Section 6. The Mathematical Model 2. Description of Model Variables We divide the human population into 11 states representing disease status and quarantine state. At any time there are the following. Denoted bythis class also includes false probable cases, that is, all those individuals who would have displayed early Ebola-like symptoms but who eventually return a negative test for Ebola Virus infection.
The class of suspected EVD patients comprises those who have come in contact with, or been in the vicinity of, anybody who is known to have been sick or died of Ebola.
Individuals in this class may or may not show symptoms. Two types of suspected cases are included: Thus a suspected case is either quarantined or not. The class of probable cases comprises all those persons who at some point were considered suspected cases and who now present with fever and at least three other early Ebola-like symptoms.
Two types of probable cases are included: Thus a probable case is either quarantined or not.
Since the early Ebola-like symptoms of high fever, headache, muscle and joint pains, sore throat, and general weakness can also be a result of other infectious diseases such as malaria or flu, we cannot be certain at this stage whether or not the persons concerned have Ebola infection. However, since the class of probable persons is derived from suspected cases, and to remove the uncertainties, we will assume that probable cases may eventually turn out to be EVD patients and if that were to be the case, since they are already exhibiting some symptoms, they can be assumed to be mildly infectious.
The class of confirmed early asymptomatic cases comprises all those persons who at some point were considered probable cases and a confirmatory laboratory test has been conducted to confirm that there is indeed an infection with Ebola Virus. This class is called confirmed early symptomatic because all that they have as symptoms are the early Ebola-like symptoms of high fever, headache, muscle and joint pains, sore throat, and general weakness.
Two types of confirmed early symptomatic cases are included: Thus a confirmed early symptomatic case is either quarantined or not. The class of confirmed early symptomatic individuals may not be very infectious.
The class of confirmed late symptomatic cases comprises all those persons who at some point were considered confirmed early symptomatic cases and in addition the persons who now present with most or all of the later Ebola-like symptoms of vomiting, diarrhea, stomach pain, skin rash, red eyes, hiccups, internal bleeding, and external bleeding.
The Ebola contagion and forecasting virus: evidence from four African countries
Two types of confirmed late symptomatic cases are included: Thus a confirmed late symptomatic case is either quarantined or not. The class of confirmed late symptomatic individuals may be very infectious and any bodily secretions from this class of persons can be infectious to other humans. Three types of removals are considered, but only two are related to EVD.
Previous Ebola virus modeling papers have examined its outbreak in Kikwit, DRC [ 14 - 16 ] and [ 1718 ]and the in Uganda in — see [ 1619 ] and [ 17 ]. Indeed, a small number of cases are reported in Nigeria 21 deaths and a single case in Senegal travelers arriving from Guinea. This consists, actually, in is the contagious Ebola virus spread among countries. Until September 8,cases had been reported, including deaths.
The first Ebola outbreak among human beings occurred in [ 20 ], with a spread contagion due mainly to travelling. An infected person travelled for instance from Guinea to Liberia may be carrying the infection, which would in turn infect some other people there The institute of tropical medicine, [ 21 ]. Based on the Ministry Health reported information SeptemberGuinea recorded confirmed deaths highly exceeding the confirmed cases.
Figures relevant to the Ebola cases and deaths have been provided by WHO, with the most prominent number being registered in Liberia, more thanwhile, probable deaths have been reported with respect to Sierra Leone. These data are based on official information reported by the Ministry of Health up the October 5th for both Guinea and Sierra Leone and October 4th for Liberia. Concerning Guinea, one might well note that the number of confirmed cases is important in respect of the probable and suspected cases.
Still, the Liberian probable cases remain the most significant in relation to the entirety of: As for Sierra Lione confirmed cases, they constitute the highest proportion as compared to the other three remaining countries. Finally, Nigeria exhibits the weakest level of cases regarding the three indicators involving confirmed, probable and suspected cases.
As a matter of fact, the Ebola virus is transmitted to human beings from wild animals, and then spreads from human-to-human. The Ebola epidemic is the most prominent in history, affecting aerial several countries. Since the beginning ofsome cases of Ebola virus infection have been reported in several sub-Saharan African countries. Travelers to or from these countries can find relevant health care related information on the Ministry of Foreign Affairs and International Development website.