Madrid (AFP) - Doctors in Spain hospitalised four more people and rushed to identify dozens of others at risk on Tuesday after a nurse was infected with the deadly Ebola virus, raising fears of contagion in Europe.
The European Union demanded answers about how the disease spread in a specialised disease unit, while health staff protested over safety failures.
The nurse was identified by Spanish media as Teresa Romero, a woman in her forties who worked at Madrid's La Paz-Carlos III hospital.
She became the first person to contract the disease outside Africa after caring for two elderly Spanish missionaries who died from the virus following their return from West Africa where the disease has killed nearly 3,500 people.
Officials said they were trying to find out who she came into contact with before being isolated on Monday. They were monitoring 52 people -- mostly health staff.
"It would be very naive to think that there is no possibility of contagion," the government's health emergencies coordinator Fernando Simon told Cadena Ser radio.
Doctors at the hospital said her husband was also at "high risk" and was put in isolation. Another "suspect case" -- a Spanish engineer recently returned from Nigeria -- was also being monitored.
Another two patients were colleagues of the nurse.
One of them was taken in for observation after suffering from diarrhoea, the hospital said.
The other is a nurse who was in contact with the infected healthworker, Spanish newspaper El Pais reported, adding that she was hospitalised by precaution as she was running a mild fever.
- Risk of contagion -
The infected nurse treated Spanish priest Miguel Pajares, 75, who contracted Ebola in Liberia and died on August 12, as well as Manuel Garcia Viejo, 69, who was repatriated from Sierra Leone and died on September 25.
She is believed to have caught the virus while caring for Garcia Viejo.
The European Commission has written to the Spanish health ministry demanding an explanation.
"There is obviously a problem somewhere," Commission spokesman Frederic Vincent said, at a time when all EU member states are supposed to have taken measures to prevent an Ebola outbreak.
However Peter Piot, one of the scientists who discovered Ebola, said while the disease posed a threat to healthcare workers around the world, there was "no risk that I see for outbreaks" in developed countries.
Spanish government officials said the nurse began to feel ill on September 30 while on leave after treating the two missionaries, but was not admitted to hospital until five days later.
Health workers' unions said the nurse had called the Carlos III hospital when she felt ill but was first referred back to a local health centre.
The hospital's director, Rafael Perez Santamarina, said she was not admitted at that time because she did not yet have a high fever or other Ebola symptoms.
The nurse's husband, named as Javier Limon by the Spanish press, told El Mundo newspaper she "did everything they told her" when she reported feeling ill.
He also vowed to fight an order by Madrid health authorities to kill their dog Excalibur over health concerns and drew the backing of animal rights groups.
Medical staff protested outside the main site of La Paz hospital in their white coats, yelling for Health Minister Ana Mato to resign.
Health worker unions complained staff had not been adequately trained.
"We do not have the infrastructure to tackle a virus like this," said Elena Moral, leader of the CSIF-AGCM union.
- Western response -
The EU announced it start airlifting 100 tonnes of relief aid on Friday to Sierra Leone, Liberia and Guinea including personal protection equipment like masks, gloves and medicines.
Dozens of British troops are due to fly to Sierra Leone next week to help build medical facilities.
British Prime Minister David Cameron will also hold an emergency meeting Wednesday to coordinate his country's response to the outbreak, his office said.
The head of the US military's Africa Command, General David Rodriguez, said American troops deployed to west Africa could stay there for up to a year.
Ebola causes severe fever, vomiting, diarrhoea and sometimes internal and external bleeding. It spreads through contact and bodily fluids.
There is no vaccine and no widely available cure, but one treatment, dubbed ZMapp, has shown promising early results and has been fast-tracked for mass production.
Some 3,439 people have died out of 7,478 cases in the current outbreak across five west African nations -- Liberia, Guinea, Sierra Leone, Nigeria and Senegal -- according to the latest WHO tally.
Patients have been treated for the disease in Europe and the United States, but until now all the cases stemmed from people who caught the virus in west Africa.
Late Tuesday, an American physician who was hospitalised in the United States after being exposed to the virus in Sierra Leone was cleared to return home to continue a 21-day observation period, after his fever abated.
European markets fell on news of the Spanish infection while the International Monetary Fund warned that economic damage from the Ebola outbreak could spread beyond west Africa and become global.