Ebola Virus: Transmission, Symptoms, Diagnosis, Treatment and Prevention

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Ebola virus
Ebola is a serious virus disease which affects human beings and other primates. Ebola is
said to be a viral hemorrhagic fever due to its severity and fatality in human beings. The rates of
fatality of this virus vary and are dependent on the strain. This viral disease first emerged in 1976
in Sudan and Zaire, and since then, there have been at least 10 outbreaks in different regions (Li
and Chen 2014). The disease has since then been a very common outbreak disease in the tropical
regions of sub-Saharan Africa. These include Guinea, Gabon, Democratic Republic of Congo
(DRC), Uganda, South Sudan, Nigeria, Mali, Senegal, Sierra Leone, Liberia, and Ivory Coast. In
2019, the intensity of transmission of this virus in the DRC has remained substantial. According
to World Health Organization (WHO) (2019), 3054 cases have been reported in DRC as of 4th of
September 2019 with 2945 confirmed cases, 109 probable cases of which 2052 have been death
cases with an overall case fatality ratio of 67%.
Transmission of Ebola
Ebola virus is usually transmitted to people through different means. According to
Malvy, McElroy, de Clerck, Günther, and van Griensven (2019), the most common form of
transmission of this virus is primarily through having a direct contact with the infected body
fluids and corpses. The fluids that may contain Ebola virus include mucus, saliva, vomit, feces,
sweat, tear, breast milk, urine and semen. In a situation where the there is lack of enough
resources, this contact can result into a major epidemic. The entry points of this deadly disease
are the nose, mouth, open wounds, cuts and abrasions, eyes, and even larger droplets. Osterholm
et al. (2015) argue that this virus is capable of surviving in dried state objects for a few hours and
few days on the body fluids which are outside human beings. This makes having contact with

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objects and surfaces that have been contaminated by the Ebola virus a mode of transmission of
the infection. Research conducted by Mate et al. (2015) reveals that Ebola virus is capable of
persisting in semen after recovery for more than 3 months. Therefore, sexual intercourse with an
infected person can result into an infection. Dead bodies and animals are very infectious and the
people handling them must take necessary precautions when disposing them off. Traditional
burial ceremonies and embalming are not recommended as they highly expose people to the
infections. Although there are no clear circumstances on how Ebola virus initially spread from
animals to human beings, it is believed that it is spread through direct contact with an infected
animal or fruit bat. Health care workers are also at risk of contracting Ebola especially when lack
appropriate protective gears, when they fail to properly handle the contaminated surfaces,
clothing and objects, when they do not properly wear their protective gears. It is important to
note that a person who has Ebola but has no symptoms of the disease cannot spread it (Lo,
Marston, Dahl and De Cock 2017). Although there has been several investigations done on this
disease, it is only believed to be a zoonotic but its natural reservoir has not yet been determined.
Signs and symptoms
The incubation period of Ebola virus ranges from 2 to 21 days after infection (Holmes,
Dudas, Rambaut and Andersen 2016). The symptoms of this disease are non-specific therefore
making the clinical diagnosis difficult. However, there are certain symptoms that can be used for
diagnosis. The early symptoms of this disease include fatigue, fever, joint and muscle pain, sore
throat, lack of appetite, weakness, and headache. The later symptoms of this disease include
vomiting, diarrhea, nausea, stomach pain, unexplained bruising for instance bloody nose,
bloodshot eyes, bloody urine, and bloody diarrhea. Some patients may also experience rash,
hiccups, cough, chest pain, difficulty in breathing, difficulty in swallowing and bleeding inside

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and outside the body. The fatality rate of Ebola virus is between 40% to 90% depending on
different factors like the species of the virus and the age of an individual (Kucharski and
Edmunds 2014). It is important to note that once the symptoms start showing, then the infected
individual is highly contagious and must be isolated so as to prevent further transmission. Also,
the people who survive are still contagious for 21-42 days after the symptoms go away
(Kucharski and Edmunds 2014). Mental confusion can also be a sign of Ebola virus infection.
Role of agent, host and environmental factors
Ebola virus disease is one of the hemorrhagic fevers caused by an infection with a virus
of the Filoviridae family of the genus Ebolavirus in the order of Mononegavirales (Malvy et al.
2019). In this genus, the genome of the viruses has a single strand of RNA enveloped in a lipid
membrane which consists of a negative polarity. The filovirus particles are known to form a long
and in some cases branched filaments of different shapes and sizes. Ebolavirus genus has five
different species of taxonomic designations. These include the Bundibugyo ebolavirus
(Bundibugyo virus), the Reston ebolavirus (Reston virus), Sudan ebolavirus (Sudan virus), Taï
Forest ebolavirus (Taï Forest virus), and Zaire ebolavirus (Ebola virus) (Malvy et al. 2019).
However, not all of them have been associated with the outbreak of diseases in human beings.
The only viruses which have so far been proved to cause diseases in human beings are Sudan,
Bundibugyo and Zaire ebolaviruses (Center for Disease Control and Prevention (CDC) n.d). The
Reston virus although pathogenic is found in nonhuman primates. On the other hand, there has
been an evolutionary overlap of rates with other viruses of RNA. Hoenen et al. (2015) argue that
the genomes of viruses from at least 5% of all the cases that have been reported have been
sequenced thereby allowing the reconstruction of Ebola virus across country borders.

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There are also few adaptive mutations which including alanine to valine which enhances
the entry of the virus into the cells of human beings during the outbreak of a strain. Upon
entering the body in an enclosed package which contains RNA, the virus specifically targets the
cells of the liver, the cells of the immune system as well as the cells of the endothelial tissues, all
of which are in line with the blood vessels. It is important to note that the virus gets into these
cells by travelling through the cell membrane, a barrier which offers protection from the cell’s
environment. Macropinocytosis, an engulfing process which allows the cell membrane to be
consumed by the virus after entering the cells through one of the pathways of nutrients intake
enables the Ebola virus cells to replicate (Tseng and Chan 2015). This in turn limits the proper
functioning of these cells or even their death. Once the virus is replicated, it then buds its viral
pieces so as to form its own cell membrane to make a capsule so as to enable its safe travel to the
nearby cells.
Ebola virus is capable of making its own protein known as the Ebola virus glycoprotein
which disrupts the adhesion of cells once it is inside (Bornholdt et al. 2016). When the cells have
difficulty in sticking together, the blood vessels start leaking hence hemorrhage as well as
internal bleeding. The virus targets the cells of the liver because it reduces its ability to clear the
toxic waste of the body thereby causing a compromise on the bloodstream as well as infecting
the immune system of the body. This leads to a rapid increase of the virus in the body area of
infection. With time, the infection can lead to severe loss of electrolytes, blood plasma and fluids
due to excessive bleeding, diarrhea and vomiting (Smith, Rawlinson, Kok, Dwyer and Catton
2015). It is important to note that the survival of Ebola virus highly depends on the host
mechanism. Human beings are not the host mechanism of this virus although they get infected
when they come into contact with the infected host.