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Ebola hemorrhagic fever (EHF; commonly referred to as simply Ebola)
is a recently identified, severe, often fatal infectious disease
occurring in humans and some primates caused by the
Ebola virus was first discovered in 1976, and since its discovery,
different strands of Ebola have caused epidemics with 50 to 90 percent
mortality in Za?e, Gabon and Uganda.
The Ebola virus
Ebola virus comes from the Filoviridae family, similar to the Marburg
virus. It is named after the Ebola River in Zaire, Africa, near where
the first outbreak in 1976 after a significant outbreak in Yambuku,
Zaire (now the Democratic Republic of the Congo), and Nzara, in
western Sudan. Of 602 identified cases, there were 397 deaths.
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The two strains identified in 1976 were named Ebola-Zaire (EBO-Z)
and Ebola-Sudan (EBO-S). The outbreak in Sudan showed a lower fatality
rate?50%?compared to the 90% mortality rate of the Zaire strain. In
1990, a second, similar virus was identified in Reston, Virginia
amongst monkeys imported from the Philippines, and was named
Further outbreaks have occurred in Zaire/Congo (1995 and 2003),
Gabon (1994, 1995 and 1996), and in Uganda (2000). A new subtype was
identified from a single human case in the C?e d'Ivoire (Ivory Coast)
in 1994, EBO-CI.
Of around 1500 identified Ebola cases, two-thirds of the patients
have died. The animal (or other) reservoir which sustains the virus
between outbreaks has not been identified.
Ebola hemorrhagic fever
Among humans, the virus is transmitted by direct contact with
infected body fluids such as blood. The cause of the index case is
The incubation period of Ebola hemorrhagic fever varies from two
days to four weeks. Symptoms are variable too, but the onset is
usually sudden and characterized by high fever, prostration, myalgia,
arthralgia, abdominal pains and headache. These symptoms progress to
vomiting, diarrhea, oropharyngeal lesions, conjunctivitis, organ
damage (notably the kidney and liver) by co-localized necrosis,
proteinuria, and bleeding both internal and external, commonly through
the gastrointestinal tract. Death or recovery to convalescence occurs
within six to ten days.
No specific treatment has been proven effective, and no vaccine
currently exists. A vaccine is in the developmental stages. Ebola is
known to exist in humans and a few monkey species can be infected. To
develop the vaccine, monkeys are used but it can not be tested on
humans except in outbreak environments so the vaccine must be tested
extensively and meet strict government regulations. Also, in the
development of a vaccine, accessibility and cost for people of poor
nations and the transportation efficiency of it must be considered.
Although there is no specific treatment for patients with Ebola,
there have been entire books written about how to prevent it from
spreading from the patient to health care workers or other patients.
The first step in prevention is to make advanced preparations for
Ebola and other viral hemorrhagic fevers (VHFs). Selecting a VHF
Coordinator to oversee preparations for VHF activities, such as the
following, does this:
Serving as the focal point for information and leadership when a
VHF case is suspected.
Informing all health facility staff about VHFs and the risks
associated with them.
Organizing training in VHF Isolation Precautions for staff that
will work with VHF patients or infectious body fluids.
Making sure that teams are trained to prepare and transport bodies
for burial (CDC 115-116).
The next step is maintaining a minimum standard of cleanliness in the
hospital. This includes washing hands and sterilizing needles (CDC
9-18). Also, the medical staff must be informed about the different
types of VHFs, including Ebola, and their symptoms. Symptoms that are
common to many VHFs are severe weakness and fatigue, and a fever for
more than 72 hours and less than three weeks. The patient also may
have unexplained bleeding from the mucous membranes, skin, eyes, or
gastrointestinal tract. The patient may also be going into shock (has
a blood pressure of less than 90 mm Hg or a rapid weak pulse).
Finally, that patient may have had contact with someone in the last
three weeks that had an unexplained illness with fever or bleeding or
who died with an unexplained severe illness with a fever (CDC 23).
The next thing to do is isolate the patient from other patients who
may get sick and health care workers who are not directly involved
with the patient's care. The patient should be given intravenous
support, as he or she is probably dehydrated from losing fluids
through vomiting and diarrhea. Finally, if the patient expires, the
body should be properly disposed of, preferably through cremation, so
that the dead body will not spread disease to other people (CDC 26).