Spanish health officials were investigating Wednesday whether a nursing assistant got Ebola by touching her face with Ebola-tainted protective gloves, while Ebola burial teams in Sierra Leone halted a strike that had left abandoned bodies in the streets of the capital.

More than 3,400 people have been killed this year by the Ebola outbreak in West Africa, which has hit Sierra Leone, Guinea and Liberia hardest. The case of Spanish nursing assistant Teresa Romero has highlighted the dangers that Ebola poses for health workers and the fact they can contact it even in sophisticated medical centers in Europe.

In Madrid, Dr. German Ramirez of the Carlos III hospital said Romero remembers she once touched her face with protection gloves after leaving an Ebola victim's quarantine room.

Health officials say Romero twice entered the room of Spanish missionary Manuel Garcia Viejo, who died of Ebola on Sept. 25 — once to change his diaper and again after he died to retrieve unspecified items. Ramirez said Romero believes she touched her face with the glove after her first entry.

"It appears we have found the origin" of Romero's infection, Ramirez said, but he cautioned the investigation was not complete.

Romero is the first person known to have caught the disease outside the outbreak zone in West Africa. She was said to be in stable condition Wednesday. Health authorities in Madrid have faced accusations of not following protocol and poorly preparing health care workers for dealing with Ebola.

In an interview with Spanish newspaper El Pais, Romero said she thought "the mistake was on taking off the suit. I see it as the most critical moment in which it could have happened, but I don't know for sure."

"I haven't got a fever today, I feel somewhat better," she told the newspaper.

In an earlier interview published by Spain's El Mundo newspaper, she had followed safety protocols as part of the team treating two priests infected with Ebola.

Her husband Javier Limon told the same newspaper that his wife went on vacation after Garcia Viejo died. She started feeling sick with a low fever Sept. 30 but still took a career advancement exam with other candidates. Health authorities say she did not leave the Madrid area during her vacation.

In another interview Wednesday with Spain's Cuatro television channel, Romero said when she started feeling sick and went to her local health center in Madrid's suburbs she didn't tell doctors she had helped treat an Ebola patient. She did not say why.

She said she had received training about how to put on and remove her hazmat suit. She declined to give an opinion about whether the training was adequate.

Yolanda Fuentes, assistant director of the Carlos III hospital, said Limon is in quarantine but has shown no symptoms of having contracted the disease.

She said of the four others taken in for observation, three — a nurse, an assistant nurse and a man who had traveled to Nigeria — had all tested negative. If they test negative again they will be released. Another nurse admitted Wednesday is under observation but has not been tested so far for the virus.

In West Africa, meanwhile, the Sierra Leone Broadcasting Corporation reported that bodies of Ebola victims were being left in homes and on the streets of Freetown because of the strike by burial teams, who complained they had not been paid. The dead bodies of Ebola victims are highly contagious.

Sierra Leone Ebola

Residents watch as health workers, not in picture, take samples from the body of a person suspected of dying from Ebola as it lies on the street in Freetown, Sierra Leone on Wednesday. (Tanya Bindra/Associated Press)

In neighbouring Liberia, health workers said they also planned to strike if their demands for more money and safety equipment were not met.

Speaking on radio Wednesday, Sierra Leone's deputy health minister Madina Rahman said the strike had been "resolved." Rahman said the dispute centred on a one-week backlog for hazard pay that had been deposited in the bank but was not given to the 600 workers on the burial teams on time.

The government was already facing criticism over a shipping container filled with medical gear and mattresses that has been held up at the port for more than a month.

In Liberia, health workers are demanding monthly salaries of $700 as well as personal protective equipment, up from below $500 per month.

"We give the government up to the weekend to address all these or else we will stop work," said George Williams of the National Health Workers Association.

Finance Minister Amara Konneh has defended the compensation for health workers, saying it was more than Sierra Leone and Guinea were offering.

Liberia's United Nations peacekeeping mission said Wednesday that an international member of its medical team had contracted Ebola, the second member of the mission to come down with the disease. The first died Sept. 25.

The mission is identifying and isolating others who may have been exposed and reviewing procedures to mitigate risk, said Karin Landgren, special representative of U.N. Secretary-General Ban Ki-moon.