What is Ebola?

Fotografía microscópica del virus Ébola

The disease caused by the Ebola virus (formerly known as Ebola fever) is a febrile hemorrhagic pathology caused by a virus of the Ebolavirus genus, which affects humans and non-human primates (monkeys, gorillas and chimpanzees). Other animals are carriers of the virus but do not develop the disease.

The natural carrier of the Ebola virus is as yet unknown. However, based on the evidence available and the nature of other similar viruses, researchers believe that this virus is transmitted by animals and that the most likely carrier is the fruit bat. The Ebolavirus genus is comprised of five different species, identified in different outbreaks: Bundibugyo (BDBV), Zaire (EBOV), Sudan (SUDV), Reston (RESTV) and Tai Forest (TAFV). It was described for the first time in 1976, in two simultaneous outbreaks in the Democratic Republic of the Congo, close to the River Ebola, and in Sudan. Four of the five known sub-types are found in a host animal native to Africa.

The Ebola virus causes a serious disease with a high rate of fatality. However, it is difficult to contract since it can only be transmitted through very close contact with a person infected and with symptoms or through contaminated biological material. It is not an airborne virus.

The current outbreak (originating from the Zaire Ebola strain), despite being the most prolonged and with the most people affected, is one of the outbreaks that, to date, has had the lowest mortality rate (below 50%).

 

Timeline of main outbreaks of the disease caused by Ebola virus

Year Country Species of the virus No. Cases Deaths Mortality rate
2014 Guinea* Zaire Ebola 1,540 904 55%
2014 Liberia* Zaire Ebola 4,665 2,705 58%
2014 Sierra Leone* Zaire Ebola 3,706 1,259 34%
2012 Democratic Republic of the Congo Bundibugyo Ebola 57 29 51%
2012 Uganda Sudan Ebola 7 4 57%
2012 Uganda Sudan Ebola 24 17 71%
2011 Uganda Sudan Ebola 1 1 100%
2008 Democratic Republic of the Congo Zaire Ebola 32 14 44%
2007 Uganda Bundibugyo Ebola 149 37 25%
2007 Democratic Republic of the Congo Zaire Ebola 264 187 71%
2005 Congo Zaire Ebola 12 10 83%
2004 Sudan Sudan Ebola 17 7 41%
2003 Congo Zaire Ebola 35 29 83%
(Nov-Dec)
2003 Congo Zaire Ebola 143 128 90%
(Jan-Apr)
2001-2002 Congo Zaire Ebola 59 44 75%
2001-2002 Gabon Zaire Ebola 65 53 82%
2000 Uganda Sudan Ebola 425 224 53%
1996 South Africa
(ex- Gabon)
Zaire Ebola 1 1 100%
1996 Gabon Zaire Ebola 60 45 75%
(Jul-Dec)
1996 Gabon Zaire Ebola 31 21 68%
(Jan-Apr)
1995 Democratic Republic of the Congo Zaire Ebola 315 254 81%
1994 Ivory Coast Cote d’Ivoire Ebola 1 0 0%
1994 Gabon Zaire Ebola 52 31 60%
1979 Sudan Sudan Ebola 34 22 65%
1977 Democratic Republic of the Congo Zaire Ebola 1 1 100%
1976 Sudan Sudan Ebola 284 151 53%
1976 Democratic Republic of the Congo Zaire Ebola 318 280 88%

(*) The figures corresponding to each country are periodically updated. Source: World Health Organization