Ebola Virus Disease

Ebola virus disease, known until 2014 as Ebola hemorrhagic (e-BO-luh hehmuh-RAH-jik), fever is a rare viral disease that causes severe internal and external bleeding, and results in death in 50 to 90 percent of those who have been infected. Its contagiousness, high lethality, and short incubation * period (three to eight days on average) have raised fears that it could be used as an agent of bioterrorism.

What Is Ebola Virus Disease?

Although much remains unknown about the Ebola virus and Ebola virus disease, scientists have begun to piece together some of the puzzle. Ebola virus disease was first identified in 1976 in Zaire (now Democratic Republic of the Congo) and was named for a river that flows through that African nation. Part of the Filovirus family, the Ebola virus had as of 2016 five known subtypes, each named for the location in which it was discovered: Zaire, Bundibugyo, Sudan, Reston, and Taï Forest. The Ebola Reston virus, first detected in the United States in 1989, was discovered in sick monkeys imported from the Philippines to a research laboratory in Reston, Virginia. Although a few laboratory workers later showed signs of the virus in their blood, none of them became ill. The Reston strain was assumed to be harmless to humans.


The first documented outbreak of Ebola virus disease occurred in 1976. At that time, it was identified as the Zaire virus, which was spread by close personal contact and the use of contaminated needles and syringes in hospitals in Zaire (now Democratic Republic of the Congo). During this outbreak, 318 people were infected and 280 (88 percent) of them died. This outbreak was the first recognition of the disease.

Between 1976 and 1979, additional outbreaks of the disease occurred but were identified as the Sudan virus. Then in 1989, the Ebola–Reston virus was introduced into quarantine facilities in Virginia and Pennsylvania by monkeys imported from the Philippines. During this event, no one was infected or died. From 1990 to 2013, the virus surfaced periodically, affected a contained group of individuals in the underdeveloped areas of the Congo, and then faded again.

But this was not the case in 2014, when the largest outbreak of the fever appeared in March. As of March 29, 2016, the World Health Organization no longer considered the outbreak a Public Health Emergency of International Concern. As of that date, there had been 28,652 suspected cases; 15,261 confirmed cases; and 11,325 deaths from Ebola in 10 countries, mostly in West Africa.

Ebola Virus Disease

Illustration by Electronic Illustrators Group. © 2016 Cengage Learning®.

How Common Is Ebola Virus Disease?

Until 2014, Ebola virus disease was considered rare. With that outbreak, scientists and healthcare personnel worked diligently to control its spread. Efforts were started to develop a vaccine to render the effects of the virus harmless in vaccinated people. In April 2016, a promising vaccine was undergoing clinical trials.

Is Ebola Virus Disease Contagious?

Ebola virus is extremely contagious. It spreads through direct contact with infected blood, especially from contaminated needles, and through contact with the nasal or respiratory secretions of an infected person. Healthcare workers and family members tending to people who have the virus are at the greatest risk of becoming infected and dying of Ebola virus infection. The needles used to take blood samples from patients are an extreme biohazard * because accidental needlesticks expose healthcare workers to the virus and are potentially life-threatening.

Some African cultural traditions may contribute to the spread of the Ebola virus. For example, some funeral rites require a ritual cleansing of the corpse, which can bring the person performing the rite into contact with blood or other body fluids of the deceased. In addition, the Ebola virus infects nonhuman primates such as monkeys and apes. Ape meat is considered a delicacy in parts of Africa, but because of the virus, scientists are recommending that people who live in these regions should avoid eating it. It may contain the Ebola virus.

How Do People Know They Have Ebola Virus Disease?

In the first few days after individuals are infected with the Ebola virus, the symptoms may vary. They often resemble those of many other diseases: fever, severe sore throat, headache, and muscle aches. The early symptoms of Ebola virus disease, however, often progress rapidly to more serious symptoms such as rash, chest pain, severe bloody vomiting and diarrhea, uncontrolled internal bleeding, kidney and liver failure, and shock * .

How Do Doctors Diagnose and Treat Ebola Virus Disease?


Doctors can diagnose Ebola virus disease on the basis of the signs and symptoms that appear in patients, as they quickly become ill during outbreaks. Blood tests can sometimes identify the virus directly, or antibodies * to the Ebola virus produced by the body during infection can be detected in the blood. Doctors must be careful when performing tests because simply injecting a needle into a patient who is prone to hemorrhage * can trigger uncontrolled bleeding.

Ebola Virus Disease

Illustration by Electronic Illustrators Group. © 2016 Cengage Learning®.

The tale reads like something from a Stephen King novel. The Ebola virus infected and killed monkeys in a laboratory in Reston, Virginia. A biohazard SWAT team descended on the Reston Primate Quarantine Unit; and working in secret just miles from the nation's capital, struggled to decontaminate the monkey house.

In his suspenseful book The Hot Zone, Richard Preston recounts in detail how the U.S. Veterinary Corps in Frederick, Maryland, detected the Ebola virus in the primate population at Reston in 1989 and recruited the secret SWAT team to contain the deadly virus.

Scientists later named the virus subtype Ebola–Reston and determined that although it is deadly to monkeys, it does not cause Ebola virus disease in humans. The following year, the same virus was found in monkeys in labs in Texas and Pennsylvania.

Researchers were able to trace the infected monkeys to a single exporter in the Philippines. In the United States, several of the monkeys died and four people were infected with the virus, although none of them became ill.


There is no specific medication to treat or cure the Ebola virus after infection occurs. Patients with Ebola virus disease are hospitalized and receive supportive care to treat symptoms. They may receive intravenous * fluids to protect against dehydration * ; monitoring of blood pressure, heart rate, and breathing; and treatment for bleeding or other infections that may develop during the illness. During past outbreaks, 50 to 90 percent of people who developed symptoms of the disease died. Those who survive usually recover in several weeks.

Researchers have discovered a protein on the surface of the Ebola virus that attaches to and damages specific cells of blood vessels. This finding may help to explain the massive bleeding that leads to most Ebola virus deaths.

A vaccine against Ebola known as VSV-EBOV was developed in Canada in 2010 and developed further by an American drug company in 2014. The vaccine underwent Phase I trials on healthy human subjects in Gabon, Kenya, and Germany. It underwent Phase II trials on healthcare workers in Guinea, one of the sites of a deadly outbreak, in 2015. The World Health Organization rated the VSV-EBOV vaccine as “highly effective,” with an effectiveness rate of 100 percent. Phase III trials of the vaccine were ongoing as of January 2016.

Can Ebola Virus Disease Be Prevented?


In 2014, there were four laboratory-confirmed cases of the Ebola virus in the United States. The first individual, Thomas Eric Duncan, died within eight days of being diagnosed. It is believed he contracted the virus while living in Liberia before moving to Texas in October 2014.

The second contracted case of the Ebola virus in the United States occurred in a nurse, Nina Pham. Pham had been assigned to care for Thomas Duncan. Within two days of his death, she showed signs of the infection. Pham never developed Ebola virus disease and has since been deemed free of the virus.

Amber Vinson, another nurse who cared for Thomas Duncan, was the third documented case of the Ebola virus in the United States. On October 14, 2014, Vinson showed signs of the infection; was isolated and treated; and by October 22 was found to be free of the virus.

The last documented case of the Ebola virus in the United States occurred on October 23, 2014, when the physician Craig Spencer arrived in New York from treating patients with Ebola in West Africa. He was admitted to the hospital, and on November 7, 2014, he was found to be free of the virus.

See also Bioterrorism Agents: Overview • Fever • Global Health Issues: Overview • Viral Infections


Books and Articles

Quammen, David. Ebola: The Natural and Human History of a Deadly Virus. New York: W. W. Norton, 2014.

Willett, Edward. What You Can Do about Ebola. New York: Enslow Publishing, 2016.


Centers for Disease Control and Prevention. “Ebola (Ebola Virus Disease).” http://www.cdc.gov/vhf/ebola/index.html (accessed June 2, 2016).

Centers for Disease Control and Prevention. “Guidance on Personal Protective Equipment (PPE) to Be Used by Healthcare Workers during Management of Patients with Confirmed Ebola or Persons under Investigation (PUIs) for Ebola Who Are Clinically Unstable or Have Bleeding, Vomiting, or Diarrhea in U.S. Hospitals, Including Procedures for Donning and Doffing PPE.” http://www.cdc.gov/vhf/ebola/healthcare-us/ppe/guidance.html (accessed March 15, 2016).

World Health Organization. “Fact Sheet: Ebola Virus Disease.” http://www.who.int/mediacentre/factsheets/fs103/en/ (accessed June 2, 2016).


Centers for Disease Control and Prevention. 1600 Clifton Rd., Atlanta, GA 30329-4027. Toll-free: 800-232-4636. Website: http://www.cdc.gov (accessed March 15, 2016).

Directors of Health Promotion and Education. 1432 K St. NW, Suite 400, Washington, DC 20005. Telephone: 202-659-2230. Website: http://www.dhpe.org (accessed March 15, 2016).

World Health Organization. Avenue Appia 20, 1211 Geneva 27, Switzerland. Telephone: 41-22-791-2111. Website: http://who.int/en/ (accessed June 2, 2016).

* incubation (in-kyoo-BAY-shun) is the period of time between infection by a disease organism and the appearance of the first symptoms. Depending on the organism, this period can extend from hours to months.

* biohazard is a biological agent or condition that poses a threat to humans.

* shock is a serious condition during which blood pressure falls very low and not enough blood flows to the body's organs and tissues. If left untreated, shock may result in death.

* antibodies (AN-tih-bah-deez) are protein molecules produced by the body's immune system to help fight specific infections caused by such microorganisms as bacteria and viruses.

* hemorrhage (HEH-muh-rij) is uncontrolled or abnormal bleeding.

* intravenous (in-tra-VEE-nus), or IV, means within or through a vein. For example, medications, fluid, or other substances can be given through a needle or soft tube inserted through the skin's surface directly into a vein.

* dehydration (dee-hi-DRAY-shun) is a condition in which the body is depleted of water, usually caused by excessive loss of body fluids that are not replaced, and occurs through sweating, vomiting, or diarrhea.

Disclaimer:   This information is not a tool for self-diagnosis or a substitute for professional care.

(MLA 8th Edition)