West Africa is counting the cost of measures to contain the deadly Ebola epidemic, as unprecedented restrictions cause food shortages, transport snarls and soaring prices, sparking fears people could die of hunger.

The United States' top disease detective calls Ebola a "painful, dreadful, merciless virus."

The World Health Organization has declared the outbreak in West Africa an international emergency, killing more than 900 people and spreading.

Zambia has banned the entry of citizens from countries hit by the deadly Ebola virus, which is ravaging nations to the north of the continent, the health ministry said Saturday.

Clinical trials of vaccines for the deadly Ebola virus should soon get underway and will likely be ready for widespread use by early next year, the World Health Organization said Saturday.

Residents of northern Liberia have existed in a state of peril for months as the deadly Ebola epidemic swept through the region. Now they face a new threat as measures to stem the spread of the virus spark fears of starvation.

Guinea on Saturday said it was closing its land borders with Liberia and Sierra Leone in a bid to halt the spread of the deadly Ebola virus which has claimed hundreds of lives in the three west African countries.

"In order to better control contact" with people suspected of carrying the Ebola virus, "Guinea has decided to temporarily close its land borders with Liberia and Sierra Leone," government spokesman Albert Damantang Camara said.

A Saudi man who died while showing symptoms similar to Ebola was not infected with the virus, according to initial test results cited by health authorities on Saturday.

The health ministry announced Wednesday that the man had died of a heart attack.

Health Minister Wael Abou Faour on Saturday urged Lebanese expats who have concerns about getting infected with the deadly Ebola virus or other epidemics to report their fears to the ministry, assuring also that treatment will be provided for them.

"We call on all Lebanese expats in Sierra Leone, Guinea, Nigeria and Liberia who are suspecting that they might have been infected with the Ebola virus or any other epidemic, or those who are seeking treatment, to reach out to the Health Ministry in Beirut through their local embassies,” a statement issued by Abou Faour said.

A Congolese nun who worked with Spanish Catholic missionaries in Liberia has died of Ebola, the charity she worked for said Saturday in Madrid.

Chantal Pascaline died early Saturday "due to Ebola at the Hospital of Saint Joseph of Monrovia" in the Liberian capital, the Hospitaller Brothers of St. John of God said in a statement.

Here are the main epidemics which have broken out over the past century, after the World Health Organisation on Friday designated the killer Ebola ravaging parts of west Africa an international health emergency: