Liz Szabo

USA TODAY

Texas health officials have placed the Dallas family of a Liberian national infected with Ebola under quarantine and ordered them not to leave their home or have any contact with outsiders for 21 days without approval of the local or state health department.

The "control order" also requires the family of Thomas Eric Duncan to be available to provide blood samples and agree to any testing required by public health officials. Officials said Thursday that the four or five family members could face criminal charges for violating the order, which was delivered to them in writing Wednesday evening.

Police have been stationed at the apartment complex to ensure residents' safety, Dallas Mayor Mike Rawlings told a news briefing Thursday afternoon.

School nurses are checking classrooms twice a day for possible symptoms among students, said superintendent Mike Miles, adding that attendance is down about 10% at schools attended by children linked to the 42-year-old Duncan.

The district also announced that three siblings who had potential contact with Duncan were removed from an elementary school for testing but that they were ultimately deemed healthy.

In an odd twist, WFAA-TV reported that five members of the Dallas County Sheriff's Department who were briefly inside Duncan's apartment have been temporarily put on leave.‎

The three deputies, a sergeant, and a lieutenant accompanied the head of Dallas County Health and Human Services Department and a doctor into the apartment late Wednesday night. They had gone there on the orders of Sheriff Lupe Valdez to get the occupants to sign a court order forbidding them from leaving the apartment.

"They're very concerned," said Christopher Dyer, president of the Dallas County Sheriff's Association. ‎"Their families are concerned. You've got to go home and tell your spouse, 'Hey, I was just inside this house where a guy had Ebola.'"

Dyer said deputies - both those that went inside and those that didn't - were told to bag up their uniforms and boots and turn them in. He said he contacted Valdez's second in command, asking that the deputies be put on leave and be evaluated by medical staff.

Also Thursday, the Plano, Texas school district informed parents that someone residing in the home of one of their elementary school students is on the Centers for Disease Control and Prevention's monitoring list of people who had contact with Duncan.

Stinson Elementary in Plano sent letters out Thursday informing parents that one person "residing in a Stinson Elementary home" is on the CDC's monitoring list. That person self-reported to the CDC and is considered "low-risk," according to district officials. The letters did not say whether or not the person on the monitoring list is a student.

Duncan, who is in serious condition with Ebola at Texas Health Presybyterian Hospital, recently arrived in the United States from Liberia. No one who has had contact with Duncan has shown any symptoms of Ebola, Dallas County Judge Clay Jenkins said at the briefing.

Ebola has infected 7,178 people and has killed 3,338 in Guinea, Sierra Leone, Liberia, Senegal and Nigeria, the World Health Organization says. The outbreaks in Nigeria and Senegal — which took swift, decisive action to control the virus — are likely over.

In other countries, however, the number of cases has been doubling every three weeks, and the CDC estimates that the disease could affect up to 1.4 million people by January if it's not quickly controlled.

Thursday night, NBC News said that a 33-year-old American freelance cameraman and writer in Liberia had tested positive for Ebola and was being flown back to the United States for or treatment. NBC did not identify the man.

Liberian authorities, meanwhile, said earlier Thursday that they would prosecute Duncan when he returns home for allegedly lying on his airport departure screening questionnaire about having had contact with an infected person.

In an exclusive interview, CNN anchor Anderson Cooper spoke with one family member, identified only as Louise, who said she, two nephews and one of her children are in the house under quarantine.

Louise, who has had at least one child with Duncan, said Duncan had suffered diarrhea and had been sweating during the night before he was hospitalized.

Louise told CNN in an interview to be broadcast Thursday evening that she is praying a lot but has no symptoms at this point. "She's taking her own temperature every hour, she says, she's taking the temperature of the young people who are in the apartment with her," Cooper said.

Because Duncan became sick at his sister's apartment, the virus is likely present in her home and in the items the family used to clean up after any vomiting or diarrhea. Dallas County is enlisting a company that has worked for area hospitals and the county to disinfect the apartment and dispose of contaminated items, including Duncan's belongings.

The Texas order covering the four or five family members also instructs them to report any symptoms immediately to Dallas County Health and Human Services. Symptoms include fever above 100.5 degrees, headache, nausea, diarrhea or abdominal pain.

The order remains in effect for 21 days — the incubation period for Ebola. After Oct. 19, family members without any Ebola symptoms are no longer considered to be at risk.

None of the family members is showing symptoms of the deadly disease, but health officials said they issued the order "out of an abundance of caution." Ebola can only be spread when someone is showing symptoms, through direct contact with bodily fluids such as blood.

"We have tried and true protocols to protect the public and stop the spread of this disease," Texas Health Commissioner David Lakey said. "This order gives us the ability to monitor the situation in the most meticulous way."

Zach Thompson, with the Dallas County Health and Human Services, told WFAA-TV on Thursday that health officials want to interview around 80 people who may be linked to Duncan.

Thompson told News 8 Daybreak that "does not mean that they are showing any symptoms, but that's the number of people that has come in contact with the patient."

Carrie Williams with the Texas Department of State Health Services said health officials are 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," Williams said. "The number will drop as we focus in on those whose contact may represent a potential risk of infection."

Texas law allows the state health department and the local health authority to issue control measures to a person who is ill with, has been exposed to or is the carrier of a communicable disease. Control measures can include isolation, quarantine and preventive therapy. If a person does not follow these orders, they can be enforced by the courts and the person can face criminal charges.

Ebola scares were knocked down in two other states Thursday.

In Hawaii, the state health department announced that a patient in isolation in a Honolulu hospital "did not meet the clinical or travel exposure criteria for an Ebola infection."

A Salt Lake City, Utah, hospital said that it had all but ruled out Ebola in one patient, calling such an infection "extraordinarily unlikely."

Contributing: WFAA-TV, Dallas-Fort Worth; Associated Press; Michael Winter, USA TODAY