LM Otero, AP
A hazmat worker cleans outside the apartment building of a hospital worker, Sunday, Oct. 12, 2014, in Dallas. The Texas health care worker, who was in full protective gear when they provided hospital care for Ebola patient Thomas Eric Duncan, who later died, has tested positive for the virus and is in stable condition, health officials said Sunday.

DALLAS — Carleen and Ed Guerrero were asleep when two police officers rapped on their door at 5 a.m. Sunday to tell them that the Ebola virus had come to their neighborhood just north of downtown.

One of their neighbors, a nurse from the apartment building just down the street, had tested positive for Ebola, and hazardous-materials crews were cleaning her apartment building, officials told the couple. It was, to say the least, unsettling news. The couple said they were still not worried about their health or safety, but said they no longer felt so distant from the virus that has dominated the news here. “It’s so close to home,” Carleen Guerrero said.

On Sunday, for the second time in two weeks, Ebola transformed part of this city into a scene of concern and contamination. Neighbors woke to Ebola-information pamphlets from the Centers for Disease Control and Prevention on their doorsteps, and to another day of uneasy questions, this time about how a hospital worker who treated the Liberian man who died last week of Ebola could have been infected despite wearing protective gloves, a gown and mask.

“We’re waiting and seeing what’s going to happen next,” said Jennifer Staubach Gates, a City Council member whose district includes the apartment complex where the Liberian victim, Thomas Eric Duncan, had been visiting his fiancée when he fell ill.

Across Dallas, people still crowded coffee shops and brunch spots, farmers markets and the State Fair on Sunday, but after public officials appeared on television Sunday morning to announce this city’s second Ebola case, concerns about Ebola and the response to it were never far from people’s minds.

But Terry Pulling, who said she had been a nurse in the early days of the AIDS epidemic, said fear and paranoia spread much easier than the virus itself.

“You’re just not going to breathe it in,” she said.

None of the neighbors said they knew the woman who had been infected, and officials did not identify her. But even people who had never walked down the block on Marquita Avenue said the realization of the disease’s proximity to their homes had changed how they viewed the disease.

“I was freaked out,” said Michelle McCoy, 23, who lives a few streets down and stopped along the tree-lined street Sunday afternoon to look at the clusters of police cars and television cameras. “It really brings it home.”