The World Health Organization (WHO) has declared the spread of Ebola in West Africa an international health emergency.

WHO officials said a coordinated international response was essential to stop and reverse the spread of the virus.

The announcement came after experts convened a two-day emergency meeting in Switzerland.

So far more than 930 people have died from Ebola in West Africa this year.

The United Nations health agency said the outbreak was an "extraordinary event".

"The possible consequences of further international spread are particularly serious in view of the virulence of the virus, the intensive community and health facility transmission patterns, and the weak health systems in the currently affected and most at-risk countries," it said in a statement.

Complex outbreak

WHO director-general Dr Margaret Chan appealed for help for the countries hit by the "most complex outbreak in the four decades of this disease".

More than 1,700 cases of Ebola have been reported in Guinea, Liberia, Nigeria and Sierra Leone.

The WHO said there would be no general ban on international travel or trade.



However, states should be prepared to detect, investigate and manage Ebola cases, including at airports, it said.

Other recommendations include:

Good surveillance to pick up potential cases

Giving people in affected countries up-to-date information on risks

Effective measures to manage risks to healthcare workers.

There were a number of challenges in affected countries, said the WHO.

These include "very weak health system capacity" and lack of medical staff, laboratory technicians and protective clothing.

But Keiji Fukuda, the WHO's head of health security, said that with the right steps and measures to deal with infected people, Ebola's spread could be stopped.

"This is not a mysterious disease. This is an infectious disease that can be contained," he said. "It is not a virus that is spread through the air."

Prof David Heymann of the London School of Hygiene & Tropical Medicine, said the recommendations were "comprehensive and evidence-based".


Symptoms include high fever, bleeding and central nervous system damage

Fatality rate can reach 90% - but the current outbreak is about 55%

Incubation period is two to 21 days

There is no vaccine or cure

Supportive care such as rehydrating patients who have diarrhoea and vomiting can help recovery

Fruit bats are considered to be virus' natural host