But on Wednesday, German Ramirez, a doctor in the Carlos III Hospital's Tropical Diseases unit, said Ramos recalled that she might have had contact with her face after leaving an Ebola patient's isolation room.
"During the course of the morning, we looked at actions taken when [the nurse’s aide] put on her protective suit," Ramirez said outside the hospital. "She has told us of the possibility that her suit had contact with her face.... It could have been an accident. It looks like it was the gloves."
Ramos became infected when she was treating Manuel Garcia Viejo, a priest who contracted the virus in West Africa. She entered Viejo's room only twice, once to change his diaper, and a second time to remove his belongings after he died on Sept. 25. She began experiencing symptoms of Ebola on Sept. 30, but was only admitted to the hospital Sunday. Tests confirmed Monday that she had contracted Ebola.
People treating patients with Ebola must wear full-body personal protective suits to prevent infection. But the process of putting on and taking off that equipment can also potentially lead to infection.
Ramos told El País that she might have made an error when she removed the suit after she cleaned the hospital room following the priest's death.
"What we've seen in the past among nurses in [West Africa] wearing [the personal protection suits] is very complicated," Daniel Epstein, a spokesman for the World Health Organization, said in an interview Tuesday. "Putting them on and taking them off requires a certain series of steps in a certain order.
"It's not that the suits fail; it's that people fail when they take it off."
Meanwhile, Spanish officials received approval from a Madrid court to euthanize her dog, Excalibur. In a plea to sympathizers, the nurse's husband, Javier Limón, who is also in quarantine in the hospital, asked the public to persuade Spanish officials to spare the mixed-breed dog's life.
"Hello, I'm Javier, the husband of Teresa Romero. I'm in the hospital, and I'm asking the population to help me to save my dog Excalibur who they [Spanish health officials] want to kill," Limón said in a video message.
The procedure was done by members of the veterinary faculty at the Universidad Complutense de Madrid, "so that he would not suffer," El Mundo added.
One scientific study found antibodies to the Ebola virus in dogs, which suggests that they might have been previously infected, Tom Frieden, director of the U.S. Centers for Disease Control and Prevention, said in a news conference Tuesday. But he added that the canines are not believed to transmit the disease.
"We have not identified this as a means of transmission," Frieden said in response to a question about the Spanish case.
Carlos Rodriguez, a Spanish veterinarian and talk-show host, said the nurse's husband reached out to him from the hospital for help, according to the AP.
Now that there is a court order to euthanize the animal, "I can't stop this happening," Rodriguez said, according to the AP. Limón "asked me, crying, to at least make sure the animal does not suffer."
On Twitter, supporters around the world have used the hashtag #SaveExcalibur.
Hospital and Spanish health officials are scrambling to find out how their systems failed to prevent Ramos from becoming infected, as tensions grow among health workers concerned for their safety in Ebola treatment wards.
"This has taken us by surprise," said Rafael Perez-Santamaria, head of the Carlos III Hospital, according to Reuters. "We are revising our protocols, improving them."
In addition to Ramos and her husband, several others were hospitalized because of suspicions that they might have Ebola. One Spanish man who had recently traveled to Nigeria and a nursing aide both tested negative for the virus in lab tests. A third nursing aide and a nurse were hospitalized with slight fevers on Tuesday night, according to the Wall Street Journal.
Limón, who also spoke to El Mundo in an interview, said that when his wife's symptoms began she stayed "mostly at home" until she was admitted to the hospital on Sunday.
Since being treated, Ramos said she is feeling "a little better."
[This post has been updated.]