MADRID—As Ebola was spreading in Africa, more than 100 Spanish nurses asked a court here in July to look at the country’s defenses. Patients with the deadly virus were certain to arrive, they wrote, and Spain’s medical system was ill-prepared to contain it.

The warning was prescient. Over the next two months, two Spanish missionaries stricken with Ebola were brought home and admitted to Spain’s pre-eminent center for highly infectious diseases—which had been taken apart in recent months after budget cuts, then hastily reassembled.

Medical workers at the center, in Madrid’s Carlos III Hospital, said they were given insufficient training and supervision for the task, one-size-fits-all protective outfits that sometimes didn’t fully cover their skin, and too little space to remove that gear safely. (Latest:Most Think U.S. Is Prepared for Ebola Virus)

The vulnerability to the virus was exposed last week when the hospital confirmed that a nursing aide who cared for the missionaries, both of whom died, had become the first person to contract it outside of West Africa.

The aide, Teresa Romero, was listed Tuesday in serious but stable condition. A doctor and eight others initially involved in her care were among 15 people under medical observation after reporting high-risk contact with her.