Ebola Virus

Ebola Virus Disease

What is Ebola Virus Disease?
Ebola Virus Disease is a rare and deadly disease most commonly affecting people and nonhuman primates (monkeys, gorillas, and chimpanzees). It is caused by an infection with a group of viruses within the genus Ebolavirus:

Ebola virus (species Zaire ebolavirus)
Sudan virus (species Sudan ebolavirus)
Taï Forest virus (species Taï Forest ebolavirus, formerly Côte d’Ivoire ebolavirus)
Bundibugyo virus (species Bundibugyo ebolavirus)
Reston virus (species Reston ebolavirus)
Bombali virus (species Bombali ebolavirus)
Of these, only four (Ebola, Sudan, Taï Forest, and Bundibugyo viruses) are known to cause disease in people. Reston virus is known to cause disease in nonhuman primates and pigs, but not in people. It is unknown if Bombali virus, which was recently identified in bats, causes disease in either animals or people.


Transmission
Scientists think people are initially infected with Ebola virus through contact with an infected animal, such as a fruit bat or nonhuman primate. This is called a spillover event. After that, the virus spreads from person to person, potentially affecting a large number of people.
The virus spreads through direct contact (such as through broken skin or mucous membranes in the eyes, nose, or mouth) with:
Blood or body fluids (urine, saliva, sweat, feces, vomit, breast milk, and semen) of a person who is sick with or has died from EVD
Objects (such as needles and syringes) contaminated with body fluids from a person sick with EVD or the body of a person who died from EVD
Infected fruit bats or nonhuman primates
Semen from a man who recovered from EVD (through oral, vaginal, or anal sex)
The Ebola virus cannot spread to others when a person shows no signs or symptoms of Ebola Virus Disease. Ebola virus is not usually transmitted by food. However, in certain parts of the world, Ebola virus may spread through the handling and consumption of bushmeat (wild animals hunted for food). There is also no evidence that mosquitoes or other insects can transmit Ebola virus.

Symptoms
Symptoms of Ebola Virus Disease include:
Fever
Severe headache
Muscle pain
Weakness
Fatigue
Diarrhea
Vomiting
Abdominal pain
Unexplained hemorrhage (bleeding)
Symptoms may appear anywhere from 2 to 21 days after contact with the virus, with an average of 8 to 10 days. Many common illnesses can have these same symptoms, including influenza (flu) or malaria.

EVD is a rare but severe and often deadly disease. Recovery from EVD depends on good supportive clinical care and the patient’s immune response. Studies show that survivors of Ebola virus infection have antibodies (molecules that are made by the immune system to label invading pathogens for destruction) that can be detected in the blood up to 10 years after recovery.

Prevention
While in an area affected by Ebola, it is important to avoid the following:
Contact with blood and body fluids (such as urine, feces, saliva, sweat, vomit, breast milk, semen, and vaginal fluids).
Items that may have come in contact with an infected person’s blood or body fluids (such as clothes, bedding, needles, and medical equipment).
Funeral or burial rituals that require handling the body of someone who died from EVD.
Contact with bats and nonhuman primates or blood, fluids and raw meat prepared from these animals (bushmeat) or meat from an unknown source.
Contact with semen from a man who had EVD until you know the virus is gone from the semen.
These same prevention methods apply when living in or traveling to an area affected by an Ebola outbreak. After returning from an area affected by Ebola, monitor your health for 21 days and seek medical care immediately if you develop symptoms of EVD.


Diagnosis
Diagnosing Ebola Virus Disease shortly after infection can be difficult. Early symptoms of EVD such as fever, headache, and weakness are not specific to Ebola virus infection and often are seen in patients with other more common diseases, like malaria and typhoid fever.
To determine whether Ebola virus infection is a possible diagnosis, there must be a combination of symptoms suggestive of EVD and a possible exposure to EVD within 21 days before the onset of symptoms. An exposure may include contact with:
blood or body fluids from a person sick with or who died from EVD
objects contaminated with blood or body fluids of a person sick with or who died from EVD
infected fruit bats and primates
semen from a man who has recovered from EVD
If a person shows early signs of EVD and has had a possible exposure, he or she should be isolated and public health authorities notified. Blood samples from the patient should be collected and tested to confirm infection. Ebola virus can be detected in blood after onset of symptoms, most notably fever. It may take up to three days after symptoms start for the virus to reach detectable levels. A positive laboratory test means that Ebola infection is confirmed. Public health authorities will conduct a public health investigation, including tracing of all possibly exposed contacts.


Treatment
Symptoms of Ebola Virus Disease are treated as they appear. When used early, basic interventions can significantly improve the chances of survival. These include:
Providing fluids and electrolytes (body salts) through infusion into the vein (intravenously).
Offering oxygen therapy to maintain oxygen status.
Using medication to support blood pressure, reduce vomiting and diarrhea and to manage fever and pain.
Treating other infections, if they occur.
Recovery from EVD depends on good supportive care and the patient’s immune response. Those who do recover develop antibodies that can last 10 years, possibly longer. It is not known if people who recover are immune for life or if they can later become infected with a different species of Ebola virus. Some survivors may have long-term complications, such as joint and vision problems.