The health of a Spanish nurse who is the first person known to have caught Ebola outside of Africa has worsened, the Madrid hospital where she is being treated said Thursday.
"Her clinical situation has deteriorated but I can't provide more information," because of the express wishes of the infected nurse, a spokeswoman for the La Paz-Carlos III hospital told reporters.
The nurse, Teresa Romero, helped treat two elderly Spanish missionaries who died after returning from west Africa with Ebola. She tested positive for the disease on Monday.
Her case has heightened concerns that the worst epidemic of Ebola on record could spread from west Africa, where it began late last year and has taken nearly 3,900 lives, mainly in Liberia, Sierra Leone and Guinea.
Romero, who is in her 40s, had gone on leave after the second of her Ebola patients died on September 25, although authorities said she did not leave Madrid.
She started to feel ill on September 29 but was not admitted to hospital until seven days later, creating a large window of time in which other people may have been exposed.
Her brother Jose Ramon said she had been intubated, was being treated by a team of 14 doctors and would receive a different treatment for Ebola.
"She has gotten worse, they have intubated her, I am not really sure but it is something pulmonary," he said during an interview with La Sexta television.
"They told me as well that they are going to try another medication, I don't remember the name," he added.
Romero had been receiving injections with antibodies extracted from blood of Ebola virus survivors, hospital officials told a news conference earlier this week.
The infected nurse said in a newspaper interview published Wednesday she believes she might have caught the deadly virus after touching her face with an infected glove after cleaning the room of one of the missionaries who died from Ebola.
Six other people are in quarantine at the hospital as a precaution, including Romero's husband and several health workers, according to the latest tally from the hospital.
Health officials said they would monitor about 50 other people -- mostly health staff -- who had been in contact with the infected nurse for the duration of the 21-day incubation period of Ebola.
The nurse's family dog -- a mixed breed mutt named Excalibur -- was put down on Wednesday as a precaution, triggering an uproar from animal rights activists.
Ebola is transmitted by close contact with the bodily fluids of a person who is showing symptoms of infection such as fever, aches, vomiting and diarrhoea, or who has recently died of the virus.