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, thereby serving as highly infectious channels of transmission even when the host is already dead.
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 EHF. The main indicator of Ebola infection is a history of travel or work in places where Ebola is endemic, including Sudan, the Democratic Republic of Congo, Côte d’Ivoire, and Gabon. A history of travel to the tropical African forests or exposure to an Ebola outbreak also increases the risk for EHF.
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.