About Ebola Virus
According to the World Health Organization (WHO), Ebola virus disease (EVD), also sometimes called Ebola hemorrhagic fever, is a serious, often deadly illness. Ebola can affect people, as well as other primates like chimpanzees, gorillas, and monkeys, and has a fatality rate of about 90 percent.
The viruses that cause Ebola belong to the family Filoverdae and the genus Ebolavirus. Five subspecies of Ebolavirus have been identifiedand four of the viruses can cause disease in humans. Fruit bats are thought to be the natural host of Ebola.
Ebolavirus was discovered in 1976 when 2 outbreaks occurredin Zaire (now the Democratic Republic of Congo; near the Ebola River) and Sudan in Africa. Ebola outbreaks usually occur in remote areas near tropical rainforests. The largest Ebola outbreak to date began in March 2014 and involves several countries in West Africa. As of August 2015, this outbreak resulted in more than 15,200 laboratory-confirmed cases of Ebolaprimarily in Liberia, Guinea, Sierra Leone, and Nigeriaand more than 28,000 probable, suspected, or confirmed cases. According to the World Health Organization, about 11,314 people died from the disease as of November 1, 2015. The World Health Organization declared the end of Ebolavirus transmission in Sierra Leone in November 2015.
The virus is can be transmitted to humans through contact with the bodily fluids and organs of infected animals. Several outbreaks are thought to have occurred from eating the un- or under-cooked meat of animals infected with the virus.
Human-to-human transmission results from direct contact with blood, secretions, organs, or other bodily fluids (e.g., saliva, urine, feces, vomit, semen) of an infected person or indirect contact with contaminated substances in the environment. During an Ebola outbreak, anyone who has close contact with an infected animal or person or the animal or person’s environment, or has contact with contaminated needles, instruments, and medical equipmentfamily members, friends, and health care workers who do not take precautionsrisk exposure to the Ebola virus.
The incubation periodlength of time from infection to the onset of symptomsfor Ebola ranges from 2 to 21 days (810 days is most common). Ebola is an acute illnesssymptoms develop suddenly.
Initial symptoms of Ebola include the following:
- Abdominal pain
- Loss of appetite
- Muscle pain
- Severe weakness
- Sore throat
Additional Ebola symptoms follow, such as:
- External and internal bleeding
- Impaired liver and kidney function
Ebola is contagious as long as the virus remains in the bodyseveral weeks to months. Diagnosing EVD involves ruling out other conditions such as malaria, typhoid fever, cholera, meningitis, and several others.
Laboratory tests used to diagnose Ebola include:
- Antibody-capture enzyme-linked immunosorbent assay (ELISA)
- Antigen detection tests
- Electron microscopy
- Reverse transcriptase polymerase chain reaction (RT-PCR) assay
- Serum neutralization test
- Virus isolation by cell culture
These tests must be conducted under maximum biologic containment conditions, as samples present an extreme biohazard risk. Some tests are used within a few days of symptom onset and others are used later in the course of the disease.
Ebola Treatment & Prevention
As of September 2014, there is no standard treatment or vaccine for Ebola. According to the World Health Organization, new drug therapies are being evaluated. Some experimental treatments have proven effective.
The Centers for Disease Control and Prevention (CDC), WHO, and other health agencies have developed guidelines to help control and prevent the spread of Ebola virus. The CDC recommends that people traveling to areas with known cases of Ebolalocations in Central and West Africatake the following precautions:
- Practice careful hygiene.
- Avoid contact with animalsbats, chimpanzees, gorillas, monkeysand blood, bodily fluids, and raw meat from these animals.
- Avoid contact with blood, bodily fluids, and items that have come in contact with blood and bodily fluids of infected peoples.
- Avoid hospitals where patients with Ebola are treated.
- Avoid burial rituals that involve handling the body or fluids of a person who has died of Ebola.
- Upon returning, monitor your health for 21 days and seek immediate medical care of you develop Ebola symptoms.
Treatment for Ebola is supportive and requires isolation and intensive care. Intravenous fluids containing electrolytes and other medications may be administered.
Sources: World Health Organization (WHO), U.S. Centers for Disease Control and Prevention (CDC)