Ebola virus disease is a serious, fatal condition in humans and nonhuman primates. Ebola is one of several viral hemorrhagic fevers, caused by infection with a virus of the Filoviridae family, genus Ebolavirus.
The mortality rates of Ebola vary depending on the strain. Ebola-Zaire can have a fatality rate of up to 90% while Ebola-Reston has never caused a fatality in humans.
READ ALSO: What is Pneumococcal Disease?
The infection is transmitted by direct contact with the blood, body fluids, and tissues of infected humans and animals. Severely ill patients require intensive supportive care. Major symptoms of Ebola virus disease (EVD) are fever, intense weakness, muscle pain, and headache.
Symptoms of Ebola
The time interval from infection with Ebola to the start of symptoms is 2-21 days, or 8-10 days. Signs and symptoms include:
Some patients may also experience:
- bleeding inside and outside of the body
- red eyes
- sore throat
- chest pain
- difficulty breathing
- difficulty swallowing
What causes Ebola?
Ebola is caused by viruses in the Ebolavirus and Filoviridae family. Ebola is considered a zoonosis, which means the virus is present in animals and is transmitted to humans.
It is yet to be known how this transmission occurs at the onset of an outbreak in humans.
In Africa, people have developed Ebola after handling infected animals found ill or dead, including chimpanzees, gorillas, fruit bats, monkeys, forest antelope, and porcupines.
READ ALSO: Infectious Diseases
Person-to-person transmission occurs after someone infected with Ebolavirus becomes symptomatic. As it can take between 2 and 21 days for symptoms to develop, a person with Ebola may have been in contact with hundreds of people, which is why an outbreak can be hard to control and may spread rapidly.
How does Ebola transmission occur in humans?
Transmission of Ebola between humans can occur through:
- Direct contact through broken skin and mucous membranes with the blood, secretions, organs, or other body fluids of infected people.
- Indirect contact with environments contaminated with such fluids.
- Exposure to contaminated objects, such as needles.
- Burial ceremonies in which mourners have direct contact with the body of the deceased.
- Exposure to the semen of people with Ebola or who have recovered from the disease – the virus can still be transmitted through semen for up to 7 weeks after recovery from illness.
- Contact with patients with suspected or confirmed EVD – healthcare workers have frequently been infected while treating patients.
There is no evidence that Ebola can be spread via insect bites.