Another 40 people are also still being monitored, but these people are considered low-risk, Lakey said.
The people being monitored include health-care workers and other members of the community who encountered Thomas Duncan, who earlier this week became first person diagnosed with Ebola in the United States.
Now that public health officials have been able to talk to everyone they considered at risk of possible contact, the overall number of people still being monitored has been cut in half since Thursday, when authorities said they were tracking 100 people.
“We’ve cast a wide net,” said Beth P. Bell, director of the Centers for Disease Control and Prevention’s center for emerging and infectious diseases. “We have a very low bar for deciding to follow patients. We’re not suggesting by this that … we have a great deal of concern about all of these people, because the reality is we have a low level of concern about the vast majority of these people that we’re following.”
The process of figuring out who to track, which is called contact tracing, involved interviewing Duncan, as well as anyone who had gone into the Dallas apartment where he was staying.
Anyone considered a high-risk person needed to be observed closely over the coming days and weeks. The list is expected to shrink again going forward, but the danger to those at highest risk would not, at least for the time being.
“Everyone who worked in the ER that night, all the way down, were at risk,” said David Kuhar, an infection control medical officer at the CDC. “You cast as wide a net as possible and then you just whittle down, whittle down.”
The CDC team split up to track down anyone who may have been exposed. Half of them stayed at the hospital to look over a list of anyone known to have had contact with Duncan from the time his symptoms began, while others met with the people in the apartment where he had stayed.
Duncan had been staying with Louise Troh at her apartment since arriving in the U.S. from Liberia on Sept. 20. He began getting ill by Thursday, at which point he sought medical treatment at Texas Health Presbyterian Hospital in Dallas. Despite the fact that he said he had traveled from West Africa and had a fever and some abdominal pain, he was diagnosed with a low-grade virus and released.
His condition worsened in the days that followed, as he developed a worse fever and felt weak and cold, before he ultimately was brought back to the hospital Sunday in an ambulance. He was placed into isolation and diagnosed Tuesday.
A person with Ebola is only contagious when they are exhibiting symptoms, which means that Duncan may have been contagious for up to four days before he was placed in isolation.
Troh, her son, a relative and a friend who had been living in the apartment at the time have been quarantined inside the home, with an official order barring them from leaving until at least Oct. 19. Duncan also had contact with the three-member ambulance team that transported him to the hospital and health-care workers at the hospital itself. No other patients at the hospital interacted with Duncan, Lakey said.
The apartment where Duncan was staying had not been cleaned until Friday afternoon, so the sheets he slept on as well as his other belongings had been sitting in sealed plastic bags in a separate room from the four quarantined people.
Authorities initially had trouble finding a company willing to do the cleaning, and once they found a company, there were new issues involving the permits allowing the company to dispose of items Duncan had touched.
“We were unable to accomplish that due to some permitting issues yesterday,” Dallas County Judge Clay Jenkins, the top elected official in the county, said in the same phone call Friday afternoon. He said that the permits still had not been obtained to dispose of these items, but said the process was “underway.”
A hazardous materials team was at the Ivy Apartments on Friday afternoon, as officials said they intended to remove all of the the bagged or otherwise contaminated items. These items were placed in large waste drums as the family waited in another room.
“The focus is to get all the material and hazardous waste out of that apartment,” Sana Syed, a spokeswoman for the city of Dallas, told reporters outside the apartment complex.
Syed tweeted photos of the team that was taking things out of the apartment on Friday afternoon:
In addition, authorities said they still planned to move the four quarantined people to a different apartment.
“I’d like to see them moved to a place that includes its own washer-drier and is a more complete living arrangement than they have now,” Jenkins said. “We are working at that.”
Even as officials in Texas provided an update on the situation there, the World Health Organization announced that the Ebola death toll is up to 3,439 in West Africa. Eight of the deaths came in Nigeria, but the balance were in the Ebola-ravaged nations of Liberia, Sierra Leone and Guinea. Through the beginning of October, there have been 7,491 probable, confirmed and suspected cases in West Africa.
And for the first time during the deadliest Ebola outbreak in history, the WHO included the U.S. in its “Ebola Response Roadmap” update. The single U.S. case brings the worldwide total to 7,492.
“We recognize that even a single case of Ebola in the United States seems threatening,” Bell said. “But the simple truth is that we do know how to stop the Ebola spread between people.”
The White House sought to reassure the public that it was ready to combat the epidemic in West Africa as well as any other potential cases in the U.S.
“The United States is prepared to deal with this crisis, both at home and in the region,” Lisa Monaco, the assistant to the president for homeland security and counterterrorism, said during a briefing Friday. “Every Ebola outbreak in the past 40 years has been stopped. We know how to do this, and we will do it again.”
Howard University Hospital in Washington, D.C., said Friday that it had admitted a patient with Ebola-like symptoms who had recently traveled from Nigeria. There have been several other cases of people across the country being tested for the virus, but Duncan is the only one who has tested positive so far.
There have also been at least five Americans infected overseas returning to the U.S. for treatment. A freelance cameraman working for NBC News has tested positive and will be flown back to the United States for care, the network announced. Ashoka Mukpo, 33, is in the early stages of the infection, according to his father.
The U.S. Army announced Friday that it would send additional troops to West Africa to help combat the epidemic. With the additional forces, the Army will send about 3,200 soldiers to help supervise the construction of Ebola treatment units, support command operations and otherwise assist in the response.
Brady Dennis, J. Freedom du Lac and Abby Ohlheiser in Washington, D.C., and Abby Phillip and Amy Ellis Nutt in Dallas, Tex., contributed to this report.
[This post has been updated. First published: 2:36 p.m. Last updated: 5:20 p.m.]