Ebola hemorrhagic fever is a disease that appears sporadically in parts of Africa. Infection with the Ebola virus causes the severe illness, which has a mortality rate of between 50 and 90 percent. There are four subtypes of Ebola virus: Ivory Coast, Sudan, Zaire and Reston Ebola. All of these viruses except the last are known to cause severe illness in people.

Symptoms typically come on abruptly and begin with fever, headache, joint and muscle aches, sort throat, and weakness. These are followed by a second wave of symptoms, which may include potentially serious symptoms such as bleeding from body orifices, seizures and coma.

Diagnosing Ebola hemorrhagic fever can be difficult, because early symptoms of this illness resemble those of other more common illnesses (e.g. malaria). However, various types of blood tests can reveal the presence of Ebola.

At present, no standard treatment for Ebola exists. Instead, patients receive supportive therapy such as fluid and electrolyte replacement, and efforts to help patients maintain a healthy blood pressure and get enough oxygen.

The best way to prevent Ebola hemorrhagic fever is to avoid the virus by not traveling to the African countries where it is known to be endemic. Healthcare workers and others who spend time around infected patients can greatly reduce the risk of contracting Ebola by wearing gowns, gloves and masks around these patients.

Ebola hemorrhagic fever is a severe disease with a high mortality rate that has appeared sporadically in some central African countries since it first was discovered in 1976. It is among a group of illnesses known as viral hemorrhagic fevers. Humans, nonhuman primates (e.g., chimpanzees, gorillas, monkeys) and certain forest antelopes can be infected with the virus that causes Ebola hemorrhagic fever. No case of the illness in humans ever has been reported in the United States.

People with Ebola hemorrhagic fever are infected with the Ebola virus, which is named after a river in the Democratic Republic of the Congo (formerly Zaire) where the virus was discovered. Ebola virus is a filovirus, one of two members of the Filoviridae family of RNA viruses (the other is Marburg virus). RNA viruses use the host cells to reproduce by turning their RNA into DNA before inserting into the hosts’ DNA. The virus contains a protein that destroys endothelial cells, the cells that line blood vessel walls. There are four subtypes of Ebola virus: Ivory Coast, Sudan, Zaire and Reston Ebola.

All of these viruses except the last are known to cause severe illness in people. Reston Ebola has caused illness and death in nonhuman primates, but not in humans. This form of virus once caused severe illness and death in monkeys at research labs in the United States, Italy and the Philippines. While several workers were infected by these monkeys, none became ill.

Much remains unknown about Ebola hemorrhagic fever. Experts still do not know its exact origin or its natural habitat. However, it is believed to be transmitted by animals (possibly bats), and cases of the illness in humans have been confirmed in the Democratic Republic of the Congo, Gabon, Sudan, the Ivory Coast and Uganda.

Ebola hemorrhagic fever usually occurs in sporadic outbreaks that arise in hospital settings (nosocomial infections) where the illness moves from patient to patient, or from patient to healthcare worker or family member. This can occur through direct contact with the blood or other bodily fluids of an infected person, or after contact with a contaminated object, such as a contaminated needle and syringe.

A very high mortality rate is associated with Ebola hemorrhagic fever, with between 50 and 90 percent of patients dying after infection. In addition, it is almost always fatal in pregnant women. However, some patients recover from the illness. Experts do not know why the illness is fatal to so many, yet is not fatal in a few patients.

In recent years, terrorism experts have raised fears that the Ebola virus could be turned into an aerosol and sprayed into the air as part of a bioterrorism attack. There have been allegations that the former Soviet Union built large stockpiles of Ebola virus with the intention of possibly aerosolizing the virus in the form of weapons of mass destruction.

Today, government officials continue to study the potential that terrorists might carry out such an attack somewhere in the world. They also continue to look for ways to prevent such an attack or to effectively treat victims of such bioterrorism.

The incubation period for Ebola hemorrhagic fever lasts for between 2 and 21 days. Symptoms typically start abruptly and begin with fever, headache, joint and muscle aches, sort throat and weakness. These are followed by a second wave of symptoms, including diarrhea, nausea, stomach pain and vomiting and other potentially serious symptoms, including:

• Bleeding from the ears, eyes, mouth, nose and rectum
  
  
• Coma
  
  
• Delirium
  
  
• Depression
  
  
• Disseminated intravascular coagulation (small blood clots in the bloodstream)
  
  
• Hemorrhagic (bleeding) rash all over the body
  
  
• Increased skin pain
  
  
• Inflammation of the eyes (conjunctivitis)
  
  
• Bleeding in internal organs
  
  
• Seizures
  
  
• Shock (life-threatening depression of organ functions)
  
  
• Swelling of the genitals (e.g., labia, scrotum)

In diagnosing Ebola hemorrhagic fever, a physician will perform a complete physical examination and compile a thorough medical history. The physician also will likely ask about any recent travel to African nations.

Diagnosing Ebola hemorrhagic fever can be difficult, because early symptoms of this illness resemble those of more common illnesses, such as malaria. However, various types of blood tests can reveal the presence of the Ebola virus. Because Ebola is so virulent and contagious, testing will likely take place in a specially designed laboratory.

At present, no standard treatment for Ebola exists. Instead, patients receive supportive therapy such as fluid and electrolyte replacement, and efforts to help patients maintain oxygen levels and blood pressure. Associated infections that may develop are also treated. When possible, patients are treated in isolation, with healthcare workers taking extra precautions (goggles and masks) to avoid exposure to the fluids that can transmit the disease.

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions related to Ebola hemorrhagic fever:

1. Am I at risk for Ebola hemorrhagic fever because I traveled to Africa?
   
   
2. What can I do to prevent Ebola hemorrhagic fever?
   
   
3. What animals might carry Ebola hemorrhagic fever viruses?
   
   
4. How will I know if my early signs and symptoms indicate hemorrhagic fever?
   
   
5. When should I seek a doctor’s care?
   
   
6. How will you diagnose my Ebola hemorrhagic fever?
   
   
7. What treatment options do I have?
   
   
8. What are my chances of survival?
   
   
9. Am I at risk of secondary infections?
   
   
10. What are the risks that Ebola hemorrhagic fever may someday appear in the United States?