Fact sheet N°103
Provisional revision: December 2008


Ebola haemorrhagic fever


The Ebola virus belongs to the Filoviridae family (filovirus) and is comprised of five distinct species: Zaïre, Sudan, Côte d’Ivoire, Bundibugyo and Reston.

Zaïre, Sudan and Bundibugyo species have been associated with large Ebola hemorrhagic fever (EHF) outbreaks in Africa with high case fatality ratio (25–90%) while Côte d’Ivoire and Reston have not. Reston species can infect humans but no serious illness or death in humans have been reported to date.

Human infection with the Ebola Reston subtype, found in the Western Pacific, has only caused asymptomatic illness, meaning that those who contract the disease do not experience clinical illness. The natural reservoir of the Ebola virus seems to reside in the rain forests of the African continent and in areas of the Western Pacific.

Transmission

Incubation period: two to 21 days.

Symptoms

Ebola is characterized by the sudden onset of fever, intense weakness, muscle pain, headache and sore throat. This is often followed by vomiting, diarrhoea, rash, impaired kidney and liver function, and in some cases, both internal and external bleeding. Laboratory findings show low counts of white blood cells and platelets as well as elevated liver enzymes.

Diagnosis

Specialized laboratory tests on blood specimens detect specific antigens and/or genes of the virus. Antibodies to the virus can be detected, and the virus can be isolated in cell culture. Tests on samples present an extreme biohazard risk and are only conducted under maximum biological containment conditions. New developments in diagnostic techniques include non-invasive methods of diagnosis (testing saliva and urine samples) and testing inactivated samples to provide rapid laboratory diagnosis to support case management during outbreak control activities.

Therapy and vaccine

Containment

Contacts

History

The Ebola virus was first identified in a western equatorial province of Sudan and in a nearby region of Zaïre (now the Democratic Republic of the Congo) in 1976 after significant epidemics in Yambuku in northern Democratic Republic of the Congo, and Nzara in southern Sudan.

About 1850 cases with over 1200 deaths have been documented since the Ebola virus was discovered.

Natural reservoir

For more information contact:

WHO Media centre
Telephone: +41 22 791 2222
E-mail: mediainquiries@who.int

[an error occurred while processing this directive]