Spanish Health Minister Ana Mato has confirmed that a nurse who treated two victims of Ebola in Madrid has tested positive for the disease.
The nurse is said to be the first person in the current outbreak known to have contracted Ebola outside Africa.
The woman was part of the team that treated Spanish priests Manuel Garcia Viejo and Miguel Pajares, who both died of the virus, officials say.
The nurse was admitted to hospital in Alcorcon, near Madrid, on Monday morning with a high fever, she said.
Meanwhile, Thomas Duncan, the first person to be diagnosed with Ebola in the US, is being treated at a Dallas hospital in isolation. He caught the virus in his native Liberia.
He has been given Brincidofovir, a new experimental drug for treating Ebola which was developed in North Carolina.
Europe at Risk
Scientists are warning that the Ebola virus could reach the UK and France by the end of the month. Following an analysis of disease spread patterns and airline traffic data, experts have predicted there is a 75 per cent chance the virus could be imported to France by October 24, while there is a 50 per cent chance it could have also hit Britain.
France is believed to be among the countries most likely to be hit next because the worst affected countries - Guinea, Sierra Leone and Liberia - include French speakers and have busy travel routes back.
Heathrow airport meanwhile is one of the world’s biggest travel hubs.
Belgium has a 40 per cent chance of seeing the disease imported, while Switzerland has lower risk of 14 per cent, according to the study first published in the journal PLoS Current Outbreaks.
Ebola spreads through contact with the bodily fluids of someone who has the virus and the only way to stop an outbreak is to isolate those who are infected.
The deadly epidemic has killed more than 3,400 people since it began in West Africa in March and has now started to spread faster, infecting almost 7,500 people so far.