The Ebola virus causes a hemorrhagic fever that is very often fatal. This filamentous virus (or filovirus) is a classic example of an infectious disease poorly adapted to humans and accidentally transmitted from animal to man (also called a ‘zoonotic’ disease). There is evidence that bats (fruit bats in particular) are the likely host. As the virus largely escapes the body’s immune system (its natural defense), it is able to spread very quickly and cause increasing organ damage.

Transmission

Transmission of the virus occurs through direct contact with the blood or other bodily fluids from a person already infected with Ebola, or through indirect contact with objects that are contaminated with blood or secretions from a sick person. Transmission is not airborne or arthropod borne.

Symptoms

Symptoms of Ebola virus disease may include one or several of the following:

• High grade fever > 38°C
• Headache
• Sore throat
• Nausea
• Vomiting
• Diarrhea
• Sometimes accompanied by bleeding (at a later stage)

Outcome

The outcome is fatal in 50-90% of the patients. There is no EMA or FDA approved treatment nor a vaccine available, but the WHO has has declared that the use of experimental drugs can be considered providing the necessary ethical standards are upheld.

Incubation

Incubation ranges from 2 to 21 days (but mostly between 3 and 7 days). There is no risk of transmission before the onset of the first symptoms (the “incubation period”) and the risk is low during the first few days after symptom onset. Note that the initial symptoms (fever, diarrhea,…) are quite non-specific, before complications develop (e.g. bleeding).

How infectious is Ebola?

Ebola is a very dangerous, but not a very contagious disease. Although the death rate is higher than 50%, infection occurs only through direct contact with blood or body fluids (saliva, sweat, feces, vomit, semen, urine, vaginal excretions and menstrual fluids), or by indirect contact with utensils contaminated with blood or body fluids of an infected person. Ill-prepared health professionals, family members and other people who have been in close contact with infected or recently deceased patients risk infection. Ebola is not spread through the air or through insect bites.

There is no risk of contamination from infected persons who are not yet sick (during the incubation period). However the risk of contamination increases after the onset of the disease, when the viral load in the body fluids is high.

Is there a risk Ebola might spread to Belgium?

Although it is possible that an infected person who has not yet developped signs of illness ends up in Belgium, it is highly unlikely that the disease will spread here. Ebola is not contagious enough and surveillance systems in Europe are sufficiently developed. In Belgium, doctors and hospitals are extra vigilant for possible symptoms and the diagnosis can be made quickly.

The limited spread of the disease in Nigeria and Senegal illustrates that the surrounding countries can potentially contain the outbreak using appropriate measures.

Who is at risk of contracting the disease?

Seen the nature of the disease and its mode of transmission, only the following people are at risk:

• People having travelled in the affected districts (see map) no longer than 3 weeks ago and who have been in close contact with patients suffering of Ebola virus infections
• Health care workers who have been in contact with infected patients.
• Family members who have been in contact with infected and deceased persons and have cared for these persons during their illness.