Texas health officials said Thursday that there are "about 100" people who may have had contact with Thomas Eric Duncan, the man who is being treated in a Dallas-area hospital for Ebola.

"We are working from a list of about 100 potential or possible contacts and will soon have an official contact tracing number that will be lower," Texas Department of State Health Services spokeswoman Carrie Williams said in a statement. "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."​

Dallas County Health and Human Services Director Zachary Thompson said that these people are not being watched or monitored and are not showing any symptoms of the illness. Only the immediate family members of the victim are being regularly monitored for Ebola symptoms; they've been ordered to stay at home and avoid contact with others.

On Wednesday, Texas officials initially said that they believed the man had contact with 12 to 18 people, including five children who attended four different schools in the Dallas area.

"Now the number has increased in terms of number of contacts," Thompson said in a phone interview. "The only [people] closely monitored at this point are the family members."

On Wednesday night, Duncan's family members received an order requiring them to stay home and comply with blood tests for the duration of the virus's potential 21-day incubation period.

Thompson said that the control order was necessary "to ensure compliance."