Ebola virus disease (EVD), also known as Ebola hemorrhagic fever, is a serious disease that often causes death. Four of the five Ebola virus strains now identified are known to cause disease in humans.
Symptoms of Ebola virus disease
Ebola virus disease takes time to spread, i.e. it has an incubation period of 2 to 21 days. The incubation period is defined as the time between when a person is exposed to the infection and when the person begins to have symptoms. Humans are not infectious until they develop symptoms. The first symptoms of Ebola virus disease
- Fever that comes on quickly
- Muscle pain
- Sore throat
Later symptoms include:
Spread of Ebola virus disease
Ebola virus disease is thought to have originated in Africa. It is believed that the virus is transmitted from wild animals to humans. These wild animals include fruit bats, monkeys, gorillas, chimpanzees, and antelope. Humans can become infected by coming into contact with fluids or organs from infected animals.
In humans, the virus is transmitted through direct contact with blood, secretions, organs or other bodily fluids of infected people. The virus enters another person through broken skin
or mucus membranes. Transmission can also occur because of direct contact with surfaces, items, and materials (bedding, clothing) contaminated with these fluids. However, the virus is not transmitted through the air. The virus can live for several hours if it has dried on surfaces. In body fluids, the virus can live for several days. The Ebola virus is destroyed with disinfectants like bleach.
Infected people are still infectious for as long as the virus remains in fluid. For instance, the semen of men who have had Ebola virus disease
and recovered can still transmit the virus for up to 7 weeks after recovery. Women can transmit the virus through breast milk.
Diagnosis of Ebola virus disease
Because early symptoms are not specific to the illness, knowing whether or not the ill person has been exposed to infected blood or fluids is key. Ebola virus disease can only be confirmed through laboratory testing
. Examples of such tests include:
- Antibody-capture enzyme-linked immunosorbent assay
- Antigen-capture detection tests
- Serum neutralization test
- Reverse transcriptase polymerase chain reaction assay
- Electron microscopy
- Virus isolation by cell culture
Treatment of Ebola virus disease
Unfortunately, there is currently no specific and proven treatment to cure Ebola virus disease
. Possible treatments are undergoing tests, including blood products, immune therapies, and drug therapies. One promising medication therapy uses three monoclonal antibodies designed to stick to the Ebola virus and prevent it from attaching to cells. There are also vaccines under development.
Prevention of Ebola virus disease
Without a proven vaccine, prevention calls for strict infection control policies and education about risk factors. Everyone should practice good hygiene, especially washing hands. This also holds true for healthcare providers
and laboratory employees who come into contact with fluids or samples from confirmed or suspected cases of Ebola virus disease. Whenever possible, avoid:
- Contact with blood and bodily fluids from a person who has or might have Ebola virus disease
- Touching items that have been in contact with a person who has or might have Ebola virus disease
- Contact with bats and primates
- Going to hospitals or other places where patients with Ebola virus disease are being treated
According to WHO, the average Ebola virus disease fatality rate is about 50%. Previously, during other outbreaks, the rate has ranged from 25% to as high as 90%.