(Fox News) A British nurse being treated for Ebola in London is in critical condition after deteriorating over the last two days, her hospital said on Saturday. The Royal Free Hospital has been treating Pauline Cafferkey, 39, with blood plasma from an Ebola survivor and an experimental anti-viral drug. She was diagnosed with Ebola on Monday after returning to Britain late on Sunday from Sierra Leone, where she had been working for the charity Save the Children at a treatment centre outside the capital, Freetown.

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Cafferkey is the first person to have been diagnosed with Ebola on British soil. The West African Ebola outbreak was first identified in Guinea’s remote southeast in early 2014. Guinea, Sierra Leone and Liberia have borne the brunt of the 20,000 infections and nearly 8,000 dead. The Royal Free, Britain’s main centre for Ebola cases, successfully treated British aid worker William Pooley with the experimental drug ZMapp after he was flown back to Britain in August.

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