Ebola virus disease (EVD) or Ebola hemorrhagic fever (EHF) is the human disease caused by ebola viruses. Symptoms start two days to
three weeks after
contracting the virus with a fever, throat and muscle pains, and headaches. There is then nausea, vomiting and diarrhea along with decreased functioning of the liver and kidneys. At this point some people begin to
have problems with bleeding.[1] The disease is first acquired
by a population when a
person comes into contact
with the blood or bodily fluids of an infected animal such as a monkey or fruit bat. Fruit bats are believed to
carry and spread the disease
without being affected by it.
Once infection occurs, the
disease may be spread from
one person to another. Men who survive may be able to
transmit the disease sexually
for nearly two months. To
make the diagnosis, typically
other diseases with similar
symptoms such as malaria, cholera and other viral hemorrhagic fever are excluded. The blood may then
be tested for either antibodies to the virus, the viral RNA, or the virus itself to confirm the diagnosis.[1] Prevention involves
decreasing the spread of the
disease from infected
monkeys and pigs to humans.
This may be done by
checking these animals for infection and killing and
properly disposing of the
bodies if the disease is
discovered. Properly cooking
meat and wearing protective
clothing when handling meat may be helpful, as may
wearing protective clothing
and washing hands when around someone sick with
the disease. Samples from
people with the disease
should be handled with an extra degree of caution.[1] There is no specific treatment
for the virus with efforts to
help people including giving
the person either oral rehydration therapy or intravenous fluids.[1] The disease has a high death
rate: often between 50% and 90%.[1][2] It typically occurs in outbreaks in tropical
regions of Sub-Saharan Africa.[1] Between 1976, when it was first identified,
and 2014, fewer than 1,000
people a year have been infected.[1][3] The largest outbreak to date is the
ongoing 2014 West Africa Ebola outbreak, which is affecting Guinea, Sierra Leone, and Liberia. A Liberian national who
recently travelled to Nigeria
died in Lagos as a result of
the disease, none of those
who had contact with him
(Mr Sawyer) got infected. The disease was first identified
in the Sudan and the Democratic Republic of the
Congo. Efforts are ongoing to develop a vaccine; however, none exists as of 2014.[1] Signs and symptoms Manifestation of Ebola begins
abruptly with a sudden onset
of an influenza-like stage characterized by general malaise, fever with chills, sore throat, severe headache,
weakness, joint pain, muscle pain, and chest pain.[4] Respiratory tract involvement is characterized
by pharyngitis with sore throat, cough, dyspnea, and hiccups. The central nervous system is affected as judged by the development of
severe headaches, agitation, confusion, fatigue, depression, seizures, and sometimes coma. Cutaneous presentation may
include: maculopapular rash, petechiae, purpura, ecchymoses, and hematomas (especially around needle
injection sites). In general,
development of hemorrhagic
symptoms is indicative of a
negative prognosis.
However, contrary to popular belief, hemorrhage does not
lead to hypovolemia and is not the cause of death (total blood loss is low except
during labor). Instead, death occurs due to multiple organ dysfunction syndrome (MODS) due to fluid redistribution, hypotension, disseminated intravascular coagulation, and focal tissue necroses. The average time between
contracting the infection and
the onset of symptoms is 13
days, but can be as long as 25 days.[5] Hemorrhage All people infected show
some extent of coagulopathy and impaired circulatory system symptomology. [6] Bleeding from mucous
membranes and puncture
sites is reported in 40–50% of cases,[7] while maculopapular rashes are
evident in approximately 50% of cases.[6] Sources of bleeds include hematemesis, hemoptysis, melena, and aforementioned bleeding
from mucous membranes (gastrointestinal tract, nose, vagina and gingiva). However diffuse bleeding
(i.e. heavy) is rare;
occurrence is usually
exclusive to the gastrointestinal tract.[6][8] Causes Main article: Ebolavirus EVD is caused by four of five
viruses classified in the
genus Ebolavirus, family Filoviridae, order Mononegavirales: Bundibugyo virus (BDBV), Ebola virus (EBOV), Sudan virus (SUDV), Taï Forest virus (TAFV). The fifth virus, Reston virus (RESTV), is thought to be not disease
causing for humans and
therefore not discussed here. Transmission EVD is believed to occur after
an ebola virus is transmitted
to a human index case via
contact with an infected animal host.[citation needed] Human-to-human
transmission occurs via direct
contact with blood or bodily
fluids from an infected
person (including embalming of an infected dead person)
or by contact with
contaminated medical
equipment such as needles.[citation needed] In the past, explosive nosocomial transmission has occurred in under-equipped
African hospitals due to the
reuse of needles and lack of
implementation of universal precautions.[citation needed] Aerosol transmission has not
been observed during natural
EVD outbreaks.[citation needed] The potential for widespread
EVD epidemics is considered low due to the high case-
fatality rate, the rapidity of
demise of patients, and the
often remote areas where
infections occur.