Spanish Health Minister Ana Mato announced in a press conference on Monday that two tests had confirmed that the nurse had been infected with Ebola, which has killed more than 3,400 people in West Africa.

Mato said health officials were already monitoring 30 people, including the nurse's husband and coworkers, for symptoms of the disease and were seeking to find out who else she may have been in contact with since developing the symptoms a few days ago.

The 40-year-old nurse checked into hospital in the Madrid suburb of Alcorcon on Sunday, despite having started to feel ill several days earlier. She was quickly placed in isolation, and the Associated Press reported that she had been transferred early on Tuesday to Madrid's Carlos III hospital, where she had helped treat two elderly Spanish missionaries who died of Ebola shortly after being brought home from Africa.

Questions raised

Health officials said they were investigating how the nurse could have become infected, as she had access to special equipment meant to protect health workers from the disease.

"We are working to see if all the protocols which were established were strictly followed," said Mato. "Spain follows all the recommendations of the World Health Organization."

Ebola's symptoms include fever, vomiting, diarrhea and sometimes internal and external bleeding. It is spread through contact with the bodily fluids of someone who has the virus.

pfd/crh (dpa, AFP, AP)