History and Prevalence

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

· Between June and November 1976 the Ebola virus infected 284 people in Sudan, with 117 deaths. In Zaire, there were 318 cases and 280 deaths in September and October. An isolated case occurred in Zaire in 1977, a second outbreak in Sudan in 1979.

· In 1989 and 1990, a filovirus, named Ebola-Reston, was isolated in monkeys being held in quarantine in laboratories in Reston (Virginia), Alice (Texas) and Pennsylvania, United States of America. In the Philippines, Ebola-Reston infections occurred in the quarantine area for monkeys intended for exportation, near Manila. Ebola-related filoviruses were isolated from cynomolgus monkeys (Macacca fascicularis) imported into the United States of America from the Philippines in 1989. A number of the monkeys died and at least four persons were infected, although none of them suffered clinical illness.

· A large epidemic occurred in Kikwit, Zaire in 1995 with 315 cases, 244 of which had fatal outcomes.

· One human case of Ebola haemorrhagic fever and several cases in chimpanzees were confirmed in Côte d'Ivoire in 1994-95.

· In Gabon, Ebola haemorrhagic fever was first documented in 1994 and outbreaks occurred in February 1996 and July 1996.

· Ebola virus infections were not reported again until the autumn of 2000 when an outbreak occurred in northern Uganda.

Excluding the most recent outbreak, nearly 1100 cases with over 800 deaths have been documented since the virus was discovered.