Ebola Virus Disease

Key facts

Ebola virus disease (EVD), formerly known as Ebola haemorrhagic fever, is a severe, often fatal illness in humans.

EVD outbreaks have a fatality rate of up to 90%.

EVD outbreaks occur primarily in remote villages in Central and West Africa, near tropical rainforests.

The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission.

Fruit bats are considered to be the natural host of the Ebola virus.

Severely ill patients require intensive supportive care. No licensed specific treatment or vaccine is available for use in people or animals.

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Transmission

Ebola is introduced into the human population through close contact with the blood, secretions, organs or other bodily fluids of infected animals. In Africa, infection has been documented through the handling of infected chimpanzees, gorillas, fruit bats, monkeys, forest antelope and porcupines found ill or dead or in the rainforest.

Ebola then spreads in the community through human-to-human transmission, with infection resulting from direct contact (through broken skin or mucous membranes) with the blood, secretions, organs or other bodily fluids of infected people, and indirect contact with environments contaminated with such fluids.

Signs and symptoms

EVD is a severe acute viral illness often characterized by the sudden onset of fever, intense weakness, muscle pain, headache and sore throat. This is followed by vomiting, diarrhoea, rash, impaired kidney and liver function, and in some cases, both internal and external bleeding. Laboratory findings include low white blood cell and platelet counts and elevated liver enzymes.

People are infectious as long as their blood and secretions contain the virus.

The incubation period, that is, the time interval from infection with the virus to onset of symptoms, is 2 to 21 days.

Diagnosis

Other diseases that should be ruled out before a diagnosis of EVD can be made include: malaria, typhoid fever, shigellosis, cholera, leptospirosis, plague, rickettsiosis, relapsing fever, meningitis, hepatitis and other viral haemorrhagic fevers.

Diagnosing Ebola HF in an individual who has been infected for only a few days is difficult, because the early symptoms, such as red eyes and a skin rash, are nonspecific to ebolavirus infection and are seen often in patients with more commonly occurring diseases.

However, if a person has the early symptoms of Ebola HF and there is reason to believe that Ebola HF should be considered, the patient should be isolated and public health professionals notified. Samples from the patient can then be collected and tested to confirm infection.

Treatment

Standard treatment for Ebola HF is still limited to supportive therapy. This consists of:

• Balancing the patient’s fluids and electrolytes

• Maintaining their oxygen status and blood pressure

• Treating them for any complicating infections

Prevention

The prevention of Ebola HF presents many challenges. Because it is still unknown how exactly people are infected with Ebola HF, there are few established primary prevention measures.

When cases of the disease do appear, there is increased risk of transmission within health care settings. Therefore, health care workers must be able to recognize a case of Ebola HF and be ready to employ practical viral hemorrhagic fever isolation precautions or barrier nursing techniques. They should also have the capability to request diagnostic tests or prepare samples for shipping and testing elsewhere.

Barrier nursing techniques include:

• Wearing of protective clothing (such as masks, gloves, gowns, and goggles)

• The use of infection-control measures (such as complete equipment sterilization and routine use of disinfectant)

• Isolation of Ebola HF patients from contact with unprotected persons

The aim of all of these techniques is to avoid contact with the blood or secretions of an infected patient. If a patient withEbola HF dies, it is equally important that direct contact with the body of the deceased patient be prevented.

Please visit these websites for more details –

http://www.who.int/mediacentre/factsheets/fs103/en/

http://www.cdc.gov/vhf/ebola/