Updated 3:08 p.m. ET
Health officials in Dallas were assessing about 100 people for possible contact with the Ebola virus Thursday, while four family members of the Texas hospital patient diagnosed with the disease were placed under quarantine Wednesday night to stem its potential spread.
Thomas Eric Duncan's close family members, who spent time with Duncan in an apartment near the north Dallas hospital where he is now battling the virus, received hand-delivered orders from Texas and Dallas County officials not to leave the apartment or to receive visitors without approval until at least Oct. 19, the end of the virus's 21-day incubation period.
The order was given after health officials grew worried about their ability to carry out necessary monitoring of the family members, which includes twice-daily check-ups to take the individuals' temperatures. Dr. David Lakey, commissioner of the Texas Department of State Health Services, cited "concern about our ability to be confident that monitoring was going to take place the way we needed it to take place.” The order is being enforced by a law enforcement official stationed outside the apartment.
The quarantined family members have taken rudimentary measures to prevent themselves from exposure to the disease, including placing Duncan's bedding and clothing in a trash bag, said health officials. The officials said they have been working to arrange a professional cleaning service for the family, which is receiving deliveries of groceries.
"There is no perfect response," said Dallas County Judge Clay Jenkins. "People are doing their best here."
Duncan remains in "serious" condition, according to a spokesperson for the hospital, Texas Health Presbyterian. He is being kept in a private ward under the care of top doctors. Duncan has access to a phone to communicate with family members, but is not allowed to receive visitors. Operations elsewhere in the hospital are unaffected.
The number of people being assessed for Ebola symptoms swelled overnight as local, state and federal officials scrambled to compile a list of anyone who had immediate or indirect contact with Duncan, the first person to develop Ebola in the United States. None of the people being monitored have exhibited any signs of the virus.
Of the roughly 100 people on the list of individuals being assessed for possible contact with the virus, only a "handful" are thought to have had potential exposure, said Dr. Thomas Frieden, the director of the Centers for Disease Control and Prevention (CDC). There are no plans to isolate additional people, officials said.
Health officials will use a technique known as contact tracing to identify the circle of people who are potentially at risk. It involves finding everyone who came into close contact with the patient and then interviewing them to identify additional potential contacts, who are subsequently tracked down and interviewed themselves. This form of shoe-leather epidemiology will continue until officials are confident that no one is at risk for contracting or spreading the virus, health officials said.
Compiling a list of possible contacts is the preliminary phase of a technique known as contact tracing. The contact tracing will be carried out by a team of five epidemiologists with the Centers for Disease Control and Prevention (CDC) in concert with county and state health officials. The process involves both phone calls and in-person visits, during which interviews are conducted and possible contacts are provided with information about the virus and informed about best practices to prevent its spread. Health officials will check in with those contacts daily to monitor for symptoms of the virus, which include high fever, severe headache, vomiting and diarrhea.
It is no surprise the tally of possible contacts has grown. Health officials are casting a very wide net, and the number of people on the list of possible contacts is expected to shrink dramatically as the investigation continues and contacts are divided into high-risk, low-risk and no risk categories, health officials said.
The majority of people being monitored did not necessarily have contact with Duncan himself, but rather with someone who Duncan encountered. "No one is symptomatic as of yet," said Erikka Neroes, a spokeswoman for Dallas County Health and Human Services, "either in the first group or that second group." Apart from the four family members under quarantine, all the people being monitored are able to move freely. Ebola is not contagious until a person shows symptoms of the virus.
Health officials are not ruling out the possibility that more Ebola cases will emerge, but they say they are confident in their ability to contain the situation. While extremely deadly, Ebola is difficult to transmit. It is communicated through bodily fluids like vomit or blood, but cannot travel through the air.
"The bottom line here is we remain confident that we can contain any spread of Ebola within the US," said Frieden. Still, he added, "there could be additional cases."