Ebola virus: A notoriously deadly virus that causes fearsome symptoms, the most prominent being high fever and massive internal bleeding. Ebola virus kills as many as 90% of the people it infects. It is one of the viruses that is capable of causing hemorrhagic (bloody) fever.
Epidemics of Ebola virus have occurred mainly in African countries including Zaire (now the Democratic Republic of Congo), Gabon, Uganda, the Ivory Coast, and Sudan. Ebola virus is a hazard to laboratory workers and, for that matter, anyone who is exposed to it.
Infection with Ebola virus in humans is incidental -- humans do not "carry" the virus. The way in which the virus first appears in a human at the start of an outbreak has not been determined. However, it has been hypothesized that the first patient (the index case) becomes infected through contact with an infected animal.
Ebola is a deadly virus originating in parts of Africa. It is classified as a hemorrhagic fever, putting it in the same category as Marburg fever, Lassa fever, and Dengue fever. There are four varieties of Ebola, named after their country of origin. Ebola Zaire, Ebola Cote d'Ivoire, and Ebola Sudan are all known to cause serious illness in human beings. Ebola Reston does not appear to cause illness in people.
Ebola may be transmitted via bodily fluids such as blood and secretions. Well-established vectors for infection include handling other primates infected with Ebola, contact with infected corpses during funeral services, and touching infected patients without exercising proper caution. It is thought that the disease may be transferred through airborne particles, but so far there are no proven cases of this method of infection. Hospital staff are particularly susceptible to infection during an outbreak, particularly in the nations in which Ebola has so far occurred. Difficult economic conditions and a lack of access to proper sterilization and protective garments make nurses and doctors an easy target when they deal with patients who have been infected with Ebola.
Contrary to popular misconception, Ebola does not kill within a matter of hours, and the virus will incubate for up to two weeks before symptoms begin to occur. These symptoms include a rapidly intensifying fever, horrible muscle pain, and debilitating weakness. Further symptoms may include diarrhea and vomiting, as well as both internal and external bleeding.
While popular media has presented the symptoms of Ebola as fast-acting and truly horrific visually, in most cases there is little external exhibition of the virus. While external bleeding may occur on occasion, it is rare, and the popular image of people "melting" or of internal organs literally liquefying is blown out of proportion. In fact, although Ebola is classified as a hemorrhagic fever, less than half of cases ultimately result in hemorrhaging. When hemorrhaging does occur, however, it is certainly capable of some grotesque exhibitions, with bleeding possibly occurring from the mouth, genitals, nose, and beneath the skin.
The first outbreak of Ebola in which the virus was identified occurred in western Sudan and part of Zaire, now known as the Democratic Republic of Congo, in 1976. More than 600 people were infected, of which more than 400 died. In 1995, a second large outbreak occurred in the Democratic Republic of Congo, infecting 315 people and killing 250. Since first being identified, more than 1800 cases of Ebola have been determined, of which 1200 resulted in deaths, making it one of the most fatal viruses to affect humans.
Bioterrorism -- There has been concern about Ebola virus as a possible weapon for bioterrorism. However, the General Accounting Office, the investigative arm of the US Congress, in a 1999 report considered Ebola virus to be an "unlikely" biologic threat for terrorism, because the virus is very difficult to obtain and process, unsafe to handle, and relatively unstable.
There is only one cause of Ebola. The cause of Ebola is an infection with the Ebola virus. There are no other causes of Ebola.
There are five known species of the Ebola virus. These include Ebola virus Zaire (EBO-Z) or Zaire Ebola virus (ZEV), Ebola virus Sudan (EBO-S) or Sudan Ebola virus (SEV), Ebola virus Côte d'Ivoire (EBO-C) or Côte d'Ivoire Ebola virus (CIEV), Ebola virus Bundibugyo (EBO-B) or Bundibugyo Ebola virus (BEV), and Ebola virus Reston (EBO-R) or Reston Ebola virus (REV). They all cause human infection, but only the first four cause hemorrhagic fever.
Ebola virus is transmitted by contact with blood, feces or body fluids from an infected person or by direct contact with the virus, as in a laboratory. People can be exposed to Ebola virus from direct contact with the blood or secretions of an infected person. This is why the virus has often been spread through the families and friends of infected persons: in the course of feeding, holding, or otherwise caring for them, family members and friends would come into close contact with such secretions. People can also be exposed to Ebola virus through contact with objects, such as needles, that have been contaminated with infected secretions.
The incubation period -- the period between contact with the virus and the appearance of symptoms -- ranges from 2 to 21 days.
The initial symptoms are usually high fever, headache, muscle aches, stomach pain, and diarrhea. There may also be sore throat, hiccups, and red and itchy eyes. The symptoms that tend to follow include vomiting and rash and bleeding problems with bloody nose (epistaxis), spitting up blood from the lungs (hemoptysis) and vomiting it up from the stomach (hematemesis), and bloody eyes (conjunctival hemorrhages). Then finally come chest pain, shock, and death.
A protein on the surface of the virus has been discovered that is responsible for the severe internal bleeding (the death-dealing feature of the disease). The protein attacks and destroys the endothelial cells lining blood vessels, causing the vessels to leak and bleed.
Ebolavirus, or Ebola, is a virus that causes a viral hemorrhagic fever (VHF). The Ebola hemorrhagic fever (EHF) is a highly lethal blood disorder that caused a mortality rate of 89% in the Democratic Republic of Congo, formerly known as Zaire, from December 2002 to April 2003. Prompt recognition of the symptoms of Ebola is essential in order to immediately initiate quarantine and supportive therapy. The most common symptoms of Ebola include severe headache, fever with or without chills, muscle or joint pains, lack of appetite, and asthenia or generalized feeling of weakness.
Together with the Marburg virus, Ebola is a virus that belongs to the family Filoviridae. When a human or a primate is infected, the Ebola virus rapidly replicates in all tissues, leading to necrosis of cells. The most damaging necrosis occurs in the liver. When the host's immune system becomes overwhelmed by the infection a fatal course occurs, and the host's blood and tissues contain large loads of the virus. In particular, body fluids and the skin have large numbers of the virions (virus particles), thereby serving as highly infectious channels of transmission even when the host is already dead.
The symptoms of Ebola hemorrhagic fever depend on the disease stage. Initially, an infected person experiences fever, inflammation of the pharynx or pharyngitis, joint pains, and muscle pains. Around the fifth day of infection, a maculopapular rash appears, usually more prominent on the trunk. Many patients also complain of bilateral conjunctivitis or sore eyes. Gastrointestinal complaints, including nausea and vomiting, abdominal pain, and diarrhea also occur in association with bleeding in the gastrointestinal tract.
Among those who are fatally infected, one important sign is obtundation, which is decreased mental alertness and diminished response to pain. At this late stage, spontaneous bleeding from mucous membranes is common. A lack of urine, increased respiratory rate, low blood pressure, and shock follow. Myocarditis and pulmonary edema are also observed. Patients often die while in coma.
There is no specific treatment for the disease. There is no known cure or vaccine for Ebola, primarily because it is exceptionally difficult to treat. If an individual is to recover from the disease, it will be because of the strength of the person's own immune system. Currently, patients receive supportive therapy. This consists of balancing the patient's fluids and electrolytes, maintaining their oxygen level and blood pressure, and treating them for any complicating infections. Death can occur within 10 days of the onset of symptoms.
When an individual is in the latter stages of the disease, the only useful actions that a medical professional can undertake are to administer fluids intravenously, control the bleeding, apply consistent oxygen levels and treat the associated infections. Chlorine is used by medical professionals to terminate the virus in an external setting.
In terms of vaccines and treatments for the Ebola virus, leading scientists, governmental organizations and educational institutions have endeavored to find a long-term and sustainable treatment. The main issue with the virus is its dynamic nature and the speed at which it permeates and penetrates the human body. The swift replication of the virus, for example, overwhelms the body's immune system.
There have been reports that ingesting an extract from a West African fruit helps to treat Ebola once it has been contracted; these reports have yet to be rigorously tested, however. Work on an Ebola vaccine is ongoing, with the recent success of a totally reliable vaccine for Ebola in monkeys. Though no human vaccine has been produced that yields positive results, the future is promising.
The prevention of the spread of Ebola fever involves practical viral hemorrhagic fever isolation precautions, or barrier nursing techniques. These techniques include the wearing of protective clothing, such as masks, gloves, gowns, and goggles; the use of infection-control measures, including complete equipment sterilization; and the isolation of Ebola fever patients from contact with unprotected persons. The aim of all of these techniques is to avoid any person's contact with the blood or secretions of any patient. If a patient with Ebola fever dies, it is equally important that direct contact with the body of the deceased patient be prevented.