Sept 28 (Reuters) - The Democratic Republic of Congo said on Friday health experts were managing to contain the spread of an outbreak of deadly Ebola haemorrhagic fever whose confirmed cases have risen to 24.

However, a senior health official said it was not yet possible to say the epidemic in Western Kasai province was under control.

* ORIGINS:

-- Ebola haemorrhagic fever (EHF) is a severe, often fatal disease in humans and non-human primates (monkeys, gorillas, and chimpanzees) that has appeared sporadically since its initial recognition in 1976.

-- The disease is caused by infection with Ebola virus, named after a river in the Democratic Republic of Congo (formerly Zaire) in Africa, where it was first recognised.

-- The Ebola virus comprises four distinct subtypes: Zaire, Sudan, Côte d'Ivoire and Reston. Three subtypes, occurring in the Democratic Republic of Congo, Sudan and the Ivory Coast, have been identified as causing illness in humans. EHF is a febrile haemorrhagic illness which causes death in between 50 and 90 percent of all clinically ill cases.

* SYMPTOMS:

-- Ebola is often characterised 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.

-- The fever has an incubation period of two to 21 days.

-- No specific treatment or vaccine is yet available.

* TRANSMISSION:

-- The Ebola virus is transmitted by direct contact with the blood, secretions, organs or other bodily fluids of infected people.

-- Burial ceremonies where mourners have direct contact with the body of the deceased person can play a significant role in the transmission of Ebola. Health care workers have frequently been infected while treating Ebola patients.

* MAJOR OUTBREAKS:

-- Between June and November 1976, EHF infected 284 people in Sudan, causing 151 deaths. In the Democratic Republic of Congo, there were 318 cases and 280 deaths in late 1976.

-- Between September 2000 and January 2001, the Sudan subtype of the Ebola virus infected 425 people, including 224 deaths, making it the largest epidemic so far of Ebola.

-- From October 2001 to December 2003, several EHF outbreaks of the Zaire subtype, were reported in Gabon and the Republic of Congo, with a total of 302 cases and 254 deaths.

-- Approximately 1,850 cases with more than 1,200 deaths have been documented since the Ebola virus was discovered.

Sources: Reuters/ U.S. Centers for Disease Control and Prevention/ World Health Organisation.

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