A doctor in Madrid says the Spanish nurse infected with Ebola remembers touching her face with her gloves after treating a dying priest.
The nurse, Teresa Romero, is the first person known to have contracted the deadly virus outside West Africa.
She treated two Spanish missionaries who died from Ebola earlier this year.
Earlier, a World Health Organization adviser warned that more Ebola cases could be expected among medical staff, even in developed countries.
Ms Romero, a 40-year-old auxiliary nurse, remains in quarantine in the Spanish capital along with her husband and three other people.
A fifth person, said to be a friend and colleague of Ms Romero, was admitted on Wednesday morning with a slight fever. In all, more than 50 people in Spain are under observation.
The infected nurse had been part of a team of about 30 staff at the Carlos III hospital in Madrid looking after the missionaries when they were repatriated from West Africa.
Miguel Pajares, 75, died on 12 August after contracting the virus in Liberia, while Manuel Garcia Viejo, 69, died on 25 September after catching the disease in Sierra Leone.