What is Ebola Virus Disease?
Ebola virus occasionally causes fatal disease that occurs primarily on the African continent. Ebola virus disease (EVD) affects mostly humans and non-human primates (monkeys, gorillas, chimpanzees, etc.). This disease is caused by infection with a series of viruses in the Ebola virus genus.
- Ebola virus (Zaire Ebola virus sp.)
- Sudan virus (Sudan Ebola virus sp. )
- Thai jungle virus (Thai jungle Ebola virus, formerly Côte d’Ivoire Ebola virus)
- Bundibugyo virus (Ebola type of Bundibugyo virus)
- Reston virus (Reston Ebolavirus sp.)
- Bombaliebolavirus (Bombali ebolavirus sp.)
Of these, only four have caused disease in humans (Ebola, Sudan, Thai Jungle, and Bundibugyo). Reston virus can cause disease in non-human mammals and pigs but has not been reported to infect humans.
Bomballi virus was first identified in bats in 2018, but experts still don’t know whether it causes disease in animals or humans.
The Ebola virus was first discovered in 1976 near the Ebola River in the Democratic Republic of Congo. Since then, the virus has occasionally infected people and caused outbreaks in several African countries. Scientists do not know where the Ebola virus came from.
Based on similar viruses, they believe that Ebola virus disease is transmitted through animals, with bats or nonhuman primates being the most likely source of infection. Infected animals carrying the virus can transmit the virus to other animals such as monkeys, apes, duikers, and humans.
This virus first infects humans through direct contact with blood, body fluids, or animal tissues. The Ebola virus is then transmitted to others through direct contact with body fluids of people who have had or died of EVD.
This can happen when a person touches these contaminated body fluids or objects contaminated with them. Then the virus enters the body through cuts in the skin and mucous membranes of the eyes, nose, and mouth.
You can get the virus through sexual contact with someone who has or has recovered from Ebola virus disease. This virus can remain in some body fluids such as semen after a person recovers from an illness.
Ebola survivors may experience side effects after recovery. These may include fatigue, muscle aches, eye, and vision problems, and stomach pain.
Signs and Symptoms
Symptoms may appear 2 to 21 days after exposure to the virus, with an average of 8 to 10 days. The course of the disease usually progresses from “dry” symptoms (such as fever, aches and pains, and fatigue) initially to “wet” symptoms (such as diarrhea and vomiting) as the condition worsens.
The main signs and symptoms of Ebola often include some or more of the following:
- Aches and pains such as severe headaches, muscle, and joint pains
- Weakness and fatigue
- Sore throat
- Loss of appetite
- Gastrointestinal symptoms such as abdominal pain, diarrhea, and vomiting
- Unexplained bleeding, bleeding, or bruising
- Other symptoms include redness, rash, and hiccups (late stage).
- Many common diseases, such as influenza (flu), malaria, and typhoid, can have symptoms similar to EVD.
Ebola virus disease is a rare but serious and often fatal disease. Recovery from Ebola depends on good supportive care and the patient’s immune response.
Studies have shown that survivors of Ebola virus infection have antibodies (proteins made by the immune system that recognize and neutralize invading viruses) that can be detected in their blood for up to 10 years after recovery. Survivors are believed to have some level of protective immunity against the type of Ebola that is making them sick.
How is Ebola spread?
- Ebola is transmitted through direct contact with blood or other bodily fluids (vomit, diarrhea, urine, breast milk, sweat, semen, etc.) from an infected person who is showing symptoms of Ebola or has recently died from Ebola.
- It can also spread through objects and surfaces contaminated with bodily fluids from the infected person, such as Clothes and bedding of the sick person if they are not washed.
- Ebola will only spread from person to person when symptoms are present.
- Ebola cannot be transmitted through air, food, or water.
- Ebola is not transmitted through casual contact.
- In some situations, Ebola can spread from sick or dead wildlife. It is not known for certain which wild animals transmit Ebola, but it has been found in bats, monkeys and apes.
- Ebola is not usually transmitted through food, but hunting, slaughtering, and processing game meat exposes people to the blood and other bodily fluids of potentially infected animals. It is illegal to bring bushmeat into the United States.
- There are currently no reports of dogs or other pets contracting Ebola or transmitting it to humans.
- There is no evidence that Ebola is transmitted by mosquitoes or other insects.
How Is Ebola Diagnosed?
The Ebola virus can be detected in the blood after the symptoms appear. After symptoms appear, it can take up to 3 days for the virus to reach detectable levels.
Polymerase chain reaction (PCR) is one of the most common diagnostic methods that can detect small amounts of the Ebola virus.
Ebola virus disease (EVD) can be difficult to diagnose soon after infection. Early symptoms of Ebola virus disease, such as fever, headache, and weakness, are not specific to Ebola virus infection and are common in patients with other more common diseases, such as malaria and typhoid.
Determining whether Ebola virus disease is a suspect diagnosis requires a combination of symptoms suggestive of Ebola virus disease and possible exposure to Ebola virus disease in the 21 days prior to symptom onset. Exposure may include contact with:
- Blood or body fluids from a person who has had or died from Ebola virus disease.
- Items contaminated with blood or body fluids from people sick with or people who have died from Ebola virus disease.
- Infected fruit bats and non-human primates (monkeys or apes), or
- Sperm from men who have recovered from EVD.
If a person is showing symptoms of EVD and has been potentially exposed, the person should be quarantined (separated from others) and public health authorities notified.
To confirm the infection, a blood sample must be taken from the patient and tested. The Ebola virus can be detected in the blood after the symptoms appear. After symptoms appear, it can take up to 3 days for the virus to reach detectable levels.
Polymerase chain reaction (PCR) is one of the most common diagnostic methods that can detect small amounts of the Ebola virus. PCR can detect the presence of small numbers of virus particles in small amounts of blood, but its ability to detect viruses increases as viral load increases during an active infection.
The PCR becomes ineffective when there are not enough viruses left in the patient’s blood. Other methods based on the detection of antibodies that produce EVD cases against infection can be used to confirm the patient’s exposure and infection with the Ebola virus.
A positive laboratory test means that the Ebola infection is confirmed. Public health officials conduct public health investigations, including identifying and monitoring all potentially exposed contacts.
How Can You Prevent Ebola?
There are vaccines to prevent Ebola, but rVSV-ZEBOV (Ervebo) only treats the Zaire strain of the virus. The best way to prevent infection is to avoid traveling to areas where the virus has been found.
If you are in an Ebola area, avoid contact with bats, monkeys, chimpanzees, and gorillas. These animals transmit Ebola to humans. A vaccine may be available from the World Health Organization.
Healthcare workers can prevent transmission by wearing masks, gloves, and goggles when in contact with someone who may have Ebola.