It is possible that the outbreak of Ebola haemorrhagic fever in Zaire could be officially declared at an end in the next two months, Dr Hiroshi Nakajima, Director-General of the World Health Organization said today. Dr Nakajima was speaking after returning to WHO's headquarters in Geneva yesterday from a fact-finding mission to Zaire.

"I hope that we will be able to announce that the epidemic is over by the end of September, and perhaps sooner," Dr Nakajima said. "However, before we can do that, a period equal to twice the maximum incubation period of the disease - that is, 42 days - needs to have passed from the date of recovery or burial of the last case, with no new cases identified through active searching. We are now counting one day at a time".

A total of 296 suspected or confirmed cases of the disease have been reported, of whom 233 are known to have died. The fact that no new case has been reported since June 20 reinforces optimism among medical experts in Zaire that the epidemic is well past its peak.

Dr Nakajima said that although the Ebola virus was the same as that which caused an outbreak in Zaire in 1976, the pattern of the latest epidemic was markedly different, in that it consisted of a series of waves of cases, whereas there was only one major wave of cases in 1976. This was due to differences in transmission of the virus, which in 1976 was largely through contaminated needles and syringes, while in the latest situation, transmission was thought to have occurred in the majority of cases directly from person to person through contact with blood or other body fluids.

The Director-General also confirmed today that WHO will organize an international medical conference to assess the latest epidemic and the national and international response to it. The conference will be held early next year in Kinshasa, Zaire.

Many thousands of residents of Kikwit, the centre of the epidemic, turned out in the streets of the city to give an enthusiastic welcome to Dr Nakajima and other WHO officials, including Dr Ebrahim Samba, the WHO Regional Director for Africa. According to local health officials, life in Kikwit has returned to normal and the welcome reflected residents' recognition of the leading role that WHO played in bringing the epidemic under control.

Dr Nakajima visited the two hospitals in Kikwit which treated the first Ebola cases and talked to doctors, local Red Cross workers, and some of the patients who are recovering from the disease. Dr Nakajima was given a full briefing by members of the International Committee on Scientific and Technical Coordination, which was set up to combat the outbreak.

Dr Nakajima outlined WHO's own plan of action on Ebola that will run until 31 December 1995. In a series of meetings during his four-day visit to Zaire, Dr Nakajima gave details of the plan to government officials, foreign diplomats, heads of United Nations agencies and other organizations based in Zaire.

The priorities of the plan are to ensure the containment of the epidemic; to better understand the Ebola virus epidemiology and its clinical manifestations; to ensure overall administrative, technical and scientific coordination of the international team in Kikwit; and to strengthen national response to potentially epidemic diseases. The plan will be implemented under the direction of Dr Samba at the WHO Regional Office for Africa in Brazzaville, Congo.

During his visit, Dr Nakajima observed a general deterioration in Zaire's health infrastructure due to the country's economic difficulties. There was a shortage of medical supplies, health workers were paid little and their pay was delayed, and there was a lack of public confidence in the health system.

The President of Zaire, His Excellency Marshall Mobutu Sese Seko, and the Prime Minister, His Excellency Mr Kengo Wa Dondo, expressed during meetings with Dr Nakajima their personal commitments to improving Zaire's health infrastructure.