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:

The devastating news didn't make sense to Brazilian Pierre Freitaz. How was it possible that, at age 17, he was infected with HIV if his only boyfriend seemed fit and healthy?

Freitaz confesses he knew little about the virus when he was diagnosed in 2004. He didn't understand the difference between the infection and the disease it caused: AIDS. He was confused by the lack of obvious symptoms.

A Canadian hospital put a patient in isolation Friday after he arrived in the country from Nigeria with symptoms of fever and flu -- possible signs he is infected with Ebola -- local media said.

Nigeria is one of several countries in West Africa that has had confirmed cases of Ebola, in the world's largest ever outbreak of the deadly hemorrhagic fever that has seen nearly 1,000 deaths and more than 1,700 people infected since the beginning of the year.

Spanish doctors said Friday that blood tests showed no sign of Ebola in a nun who was evacuated from Liberia along with an elderly missionary infected with the deadly virus.

The Spanish nun, 65-year-old Juliana Bonoha Bohe, was flown to Madrid on Thursday along with 75-year-old Roman Catholic priest Miguel Pajares, who contracted Ebola while helping hospital patients in the Liberian capital Monrovia.

Nigeria's president on Friday declared a national emergency over the deadly Ebola virus that has claimed two lives in Africa's most populous country.

"President Goodluck Ebele Jonathan Friday in Abuja declared the control and containment of the Ebola virus in Nigeria, a national emergency," his office said in a statement.

Nurses taking nervous passengers' temperatures at airports and isolation wards standing eerily empty waiting to receive anyone showing symptoms -- the world was already on the lookout for Ebola victims before the WHO issued a global alert on Friday.

Concern is highest in the west African neighbors of the countries -- Liberia, Guinea and Sierra Leone -- which are worst affected by an outbreak that has killed nearly 1,000 people.