The health of a Spanish nurse with Ebola worsened on Thursday and four other people were put into isolation in Madrid, while the country's government rejected claims its methods for dealing with the disease weren't working and blamed human error.

Teresa Romero, 44, is the first person to have contracted Ebola outside of Africa, after becoming infected by one of two Spanish priests repatriated from Africa with the disease.

In total seven people are in isolation in Madrid, though only Romero has tested positive for Ebola. The others include the nurse's husband and two doctors who cared for her. Three other people were released from the isolation unit late on Wednesday after testing negative.

A health official at the Carlos III Hospital where Romero is being treated said on Thursday: "Her clinical situation has deteriorated but I can't give any more information due to the express wishes of the patient."

The European Commission asked the Spanish government for an explanation of how Romero's infection happened in a high-security ward. One political official pointed out that Romero told another doctor at the hospital that she touched her face with her protective gloves.

"It's obvious that the patient herself has recognized that she did not strictly follow the protocol," Ruben Moreno, spokesman for health for the ruling People's Party, said in a television interview.

Health workers - whose unions have called for the resignation of Spanish Health Minister Ana Mato - expressed growing anger that training and protective suits provided to hospital staff had been inadequate.

One nurse, who worked alongside Romero on the isolation ward while caring for the priests, said the government was trying to shift the blame for any lapse in protocol.

"We are really angry," Elena, who declined to give her second name, said outside the gates of the Carlos III Hospital. "She is the victim and they are criminalizing her as if she was the one responsible for all that has happened."

Another doctor, who cared for Romero and is among those now in isolation, said the sleeves on the protective suit he wore while handling her had been too short.

In a letter to healthcare authorities, published by national newspaper El Pais, the doctor detailed treating Romero during a gruelling 16-hour shift during which he was not told she had the Ebola virus. He said he only learned of this via the press.

The hospital has now cleared its fourth floor to accommodate around 10 workers who are caring for the seven people in isolation on the sealed-off sixth floor.

CALLS FOR CALM

The Ebola virus has killed nearly 4,000 people in West Africa since March in the largest outbreak on record. It causes hemorrhagic fever and is spread through direct contact with body fluids from an infected person.

The World Health Organization has said it sees no evidence of the disease being brought under control in Liberia, Sierra Leone and Guinea. The first person diagnosed with Ebola in the United States died on Wednesday and the U.S. government ordered extra screenings at five major airports - something the European Union is now discussing.

Currently, passengers at airports in Africa must fill out questionnaires and be checked for high body temperature, one of the symptoms of Ebola. The only major European airline still running direct flights to the worst-hit countries is Brussels Airlines, part-owned by Lufthansa. British Airways halted flights to Liberia and Sierra Leone in August.

News of the contraction of the Ebola virus in their country has deeply shaken Spaniards' faith in the government and the health system, which has suffered deep spending cuts as part of austerity measures over the past years.

Although there are no signs of panic in Madrid, one resident in the suburb where Romero lived said some people had cancelled hospital appointments and some parents had not taken their children to the nursery near the health centre where she had first gone complaining of fever.

"A lot of children did not turn up at the nursery next to the health centre and some cancelled hospital appointments as a matter of caution," said Josefa Sierra, 67, member of a neighbour's association in the Madrid suburb of Alcorcon.

"Of course people are talking of little else when you go to do the shopping at the supermarket," she said. "But there's no panic, no. It's not as though people are staying at home."

While newspapers run columns and diagrams on the life-cycle of the virus, Prime Minister Mariano Rajoy has called for calm and said a major outbreak was extremely unlikely.

The investigation into how Romero contracted the disease continues. A spokesman for the Madrid health department also said the ambulance that collected Romero from her home, while disinfected between trips, went on to carry other patients to hospital without being taken out of circulation until she was known to have contracted Ebola.

Patients carried in the ambulance were unlikely to have caught the disease as they did not have direct contact with the nurse, but were being monitored, the spokesman said. He could not say how many travelled in the ambulance, although press reports put it at seven patients.