Ebola Virus FAQ

The Ebola virus is a single-stranded RNA virus that belongs to the Filoviridae family (filovirus). There are five distinct strains; -

Zaïre - causes Ebola in humans. Has the highest fatality rate.

Sudan -causes Ebola in humans, and was the second Ebola strain to be discovered.

Côte d’Ivoire - causes Ebola in humans. Also known as the Ivory Coast Ebola Virus

Bundibugyo - causes Ebola in humans and was discovered in 2007 after an outbreak in the Bundibugyo district of Uganda

Reston - causes Ebola in non-human primates; it is non pathogenic in humans.

According to the World Health Organisation (WHO) there have been 1850 cases of Ebola infection since the virus was discovered in 1976. And these have resulted in over 1200 deaths. These figures are correct as of November 2009.

There have been several outbreaks and epidemics since 1976.

• 1976: 151 deaths in Sudan, 280 deaths in the Democratic Republic of Congo
• 1979: 22 deaths in Sudan
• 1994: 9 deaths in Gabon
• 1995: 250 deaths in the Democratic Republic of Congo
• 1996: 45 deaths in Gabon
• 2000-2001: 224 deaths in Uganda
• 2001-2003: 254 deaths in Gabon and the Democratic Republic of Congo
• 2007-2008: 37 deaths in Uganda

Simultaneous outbreaks occurred in Zaire (now known as the Democratic Republic of Congo) and the western equatorial province of Sudan in 1976. More than 400 people were killed.

The exact origin and natural reservoir of the Ebola virus is still a mystery, despite exhaustive studies. Its location appears to be the rain forests of the African continent and the Western Pacific. Although non-human primates - gorillas, chimpanzees, monkeys - are the source of the infection for humans they are not considered to be the natural reservoir. Current thinking is that they are infected directly from the natural reservoir or through an infectious chain that starts with the natural reservoir.

A paper in the scientific journal Nature in 2005 reported that bat species captured during outbreaks in Gabon and the Republic of Congo (2001-2003) were infected with Ebola but showed no symptoms. This suggests that they may play a role in spreading the virus- either by passing it to great apes, or even infecting humans directly. In the first outbreak in Sudan in 1976 bats were found in the roof of a cotton factory where a number of people died from the disease.

As the natural reservoir is unknown scientists still haven't figured out how Ebola first appears in a human at the start of an outbreak. It is thought that a person is struck down by the virus after coming into contact with an infected animal.

Ebola virus is extremely contagious and it can spread from person to person via bodily fluids and secretions. So close family members and medical workers are at risk when tending to an infected person. People can also catch Ebola from coming into contact with objects such as needles that are infected with the virus. The bodies of people who have died from the disease are still infectious.

Medline Plus Haemorrhagic Fevers

World Health Organisation - Ebola