How is Ebola treated, how easy is it to contract it, can it be prevented and how likely is it to spread from west Africa? The National Institute for Communicable Diseases (NICD) answers these pressing questions.
What is Ebola virus disease?
Ebola virus disease (EVD) was previously known as Ebola haemorrhagic fever.
It is a severe, often fatal disease in humans and nonhuman primates (monkeys, gorillas and chimpanzees).
EVD is caused by a virus, and first appeared in 1976 when two outbreaks (one in an area near the Ebola River in Democratic Republic of Congo, and the other in South Sudan) occurred. Since then, sporadic outbreaks have occurred, most commonly in the Democratic Republic of Congo, Uganda, South Sudan, Congo and Gabon.
The origin of Ebola virus is not known, but fruit bats are thought to be the likely host of the virus.
How do people become infected with Ebola virus?
Ebola virus is transmitted to humans through direct contact with the blood, secretions, organs or other bodily fluids of infected animals (which include chimpanzees, gorillas, bats, monkeys, forest antelope and porcupines). This occurs when hunters/other persons come into contact with dead animals found lying in the rainforest, or handling raw meat of infected animals.
Once a person is infected, the Ebola virus can spread to other people in the community.
Infection occurs from direct contact (through broken skin or mucous membranes, including the nose, eyes and mouth) with blood, or other bodily fluids and secretions (including stool, urine, saliva, semen) of infected people.
Less commonly, infection can also occur from direct contact (through broken skin or mucous membranes, including the nose, eyes and mouth) with environments that are contaminated with an Ebola patient’s infectious blood or body fluids, such as soiled clothing, bed linen, or used needles.
Burial ceremonies in which mourners have direct contact with the body of the deceased person have also been responsible for spreading infection in some outbreaks.
Who is at risk for becoming infected with Ebola virus?
During EVD outbreaks, the following persons are most at risk for infection: Healthcare workers
Family members or friends in close contact with infected people, because they come in close contact with infectious secretions/bodily fluids when caring for ill persons
Mourners who have direct contact with the bodies of the deceased as part of burial ceremonies
Hunters/other persons in the rain forest who come into contact with infected animals in the forest
What are the signs and symptoms of EVD?
After infection with the Ebola virus, there is an incubation period of 2 – 21 days (on average, 8 – 10 days) after which the person will start to experience symptoms. The initial symptoms include fever, weakness and lethargy, muscle pain, headache and sometimes sore throat.
This is followed by vomiting, diarrhoea, abdominal pain, and sometimes a rash. Some patients may experience bleeding inside and outside of the body; this is the most serious complication.
How is EVD diagnosed?
EVD can only be confirmed through laboratory testing, usually a blood test. A specialised laboratory at the National Institute for Communicable Diseases in Johannesburg is able to test for Ebola virus infection.
What is the treatment of EVD?
There is no medication available to treat the Ebola virus itself. Standard treatment for EVD is limited to supportive therapy, and severely ill patients require intensive supportive care. This consists of balancing the patient’s fluids and electrolytes, maintaining their oxygen status and blood pressure, and treating them early for any complicating infections.Some patients will recover with the appropriate medical care.
To control further spread of Ebola virus, patients that are suspected to have EVD should be isolated from other patients and treated by healthcare workers using very strict precautions to prevent being infected.
Experimental treatment has been tested in animal models, but has not yet been used in humans.
Can EVD be prevented?
There is no licensed vaccine for EVD. Several vaccines are being tested, but none are available for clinical use as yet. Preventing initial cases is challenging, since it is still not known how exactly Ebola virus is maintained in nature and what preventive interventions would be successful.
Once an initial case of EVD occurs in a community, preventing spread to other people is critical. This includes educating the general public about the disease and how it can be prevented from spreading further.
How can healthcare workers protect themselves from infection with Ebola virus?
Healthcare workers are at high risk of exposure to the virus when caring for Ebola patients, and need to apply additional infection control precautions over and above the standard healthcare precautions.
This includes wearing personal protective equipment (including gloves, masks, gowns and goggles), ensuring complete equipment sterilisation, and the routine use of disinfectant. Infected patients must be isolated from other patients and cared for by staff who are trained in the appropriate infection control measures.
Is it safe to travel during an outbreak of EVD?
The World Health Organization regularly reviews the public health situation and recommends any travel or trade restrictions if necessary. At present, no travel or trade restrictions are recommended.
The risk of infection for travellers is very low, even if the visit included travel to the local areas from which primary cases have been reported.
Infection with Ebola virus requires direct contact with blood, secretions, organs or other body fluids of infected living or dead persons or animals, all of which are unlikely exposures for the average traveller.
There is no risk of Ebola virus transmission during the incubation period and only low risk of transmission in the early phase of disease.
Historically, several cases of haemorrhagic fever (Ebola, Marburg, Lassa, Crimean Congo haemorrhagic fever) disease were diagnosed after long-distance travel but none developed the symptoms during the international travel and no persons who came into contact with the patients during travel were infected.
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