Updated at 3:42 p.m. ET:

The number of "contact traces" for a man diagnosed with Ebola earlier this week in Dallas has risen to 100, officials say, as they add secondary contacts to a list of people being monitored for symptoms of the deadly virus.

Earlier today, Erikka Neros, a spokeswoman for the Dallas County Health and Human Services department, said the number of "contact traces" stood at about 80 because the 12 to 18 people who had been exposed directly to the patient then had contact with others.

Hours later, a spokeswoman with the Texas Department of State Health Services said officials were "working from a list of about 100 potential or possible contacts."

"Out of an abundance of caution, we're starting with this very wide net, including people who have had even brief encounters with the patient or the patient's home. The number will drop as we focus in on those whose contact may represent a potential risk of infection," the spokeswoman, Carrie Williams, said in a statement.​

Health officials have repeatedly emphasized that the monitoring is a precaution and that the likelihood that anyone on the list would contract Ebola is very low.

Neros said those people who may have had secondary contact have been reached by public health officials and given information about the signs and symptoms of Ebola. They are being asked to take their temperatures daily on their own and report any signs or symptoms to the authorities, she said.

The infected man, who was admitted to Texas Health Presbyterian Hospital in Dallas on Sunday, has been identified as Thomas Eric Duncan.

The Texas Department of State Health Services (TDSHS) said it had to order four close family members to stay home and receive no visitors until at least Oct. 19, when officials believe the incubation period for the virus would be over.

"The local health department had previously instructed the family to stay home, but a strict public health control order is needed to ensure compliance," TDSHS said in a statement.

During a press conference in the afternoon, officials said that none of the family members had symptoms, so the risk of transmission is zero.

Among those who had contact with Duncan were five children, officials said.

The Associated Press says: "Some parents in Dallas are keeping their children home from school today after learning that several other students may have come in contact with the man who was diagnosed with the Ebola virus after flying from Liberia to Texas. School administrators are urging calm, and they say none of the children are showing symptoms. The infected man had traveled to the U.S. to visit family, and he didn't show symptoms until several days after his arrival. But a hospital in Dallas sent him home the first time he reported feeling sick."

Hospital officials confirmed Wednesday that Duncan was sent home after an initial exam on Friday concluded he suffered from a "low-grade common viral disease." The hospital said that although a nurse, working from an Ebola checklist, determined that he had recently traveled from Liberia, that information was "not communicated to the full team." Liberia has been the focus of the epidemic in West Africa.

The New York Times reported on Wednesday that while in Liberia, Duncan had helped a pregnant woman with Ebola get to the hospital.

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