London, Jan 4 (IANS): A British nurse, who was diagnosed with Ebola after returning from Sierra Leone, is now in a critical condition, a hospital said.

Doctors at the Royal Free Hospital in London said that Pauline Cafferkey’s condition was downgraded to “critical” BBC reported Saturday.

"The Royal Free London NHS Foundation Trust is sorry to announce that the condition of Pauline Cafferkey has gradually deteriorated over the past two days and is now critical," hospital officials said in a statement.

Cafferkey, the first Ebola patient on British soil, had traveled to Sierra Leone to treat victims from the latest Ebola outbreak in West Africa.

"We are giving her the very best care possible. However, the next few days will be crucial. The disease has a variable course and we will know much more in a week's time," said Dr. Michael Jacobs.

On Friday, the World Health Organization (WHO) said the number of fatalities due to the Ebola epidemic in Africa has soared to nearly 8,000.

Ebola is a form of hemorrhagic fever with diarrhea, vomiting, as well as internal and external bleeding as its symptoms.

The virus spreads through direct contact with the bodily fluids of an infected person. Those who care for the Ebola-infected patients or handle their bodies are particularly exposed and endangered.