— A patient at Duke University Hospital who developed a fever Sunday after returning from Liberia tested negative Monday morning for Ebola, state health officials said.

The person – whose privacy health officials were respecting in not releasing information about age, race or gender – arrived at Newark Liberty International Airport on Saturday, took a taxi to a bus station, then met family members at a Durham County bus depot early Sunday, according to Dr. Aldona Wos, state Secretary of Health and Human Services.

"Based on today's conversation with U.S. Centers for Disease Control and Prevention, the negative result indicates this person was not contagious and posed no health or safety threat during travels to North Carolina or to Duke," Wos said Monday afternoon.

The unidentified person will remain in secure isolation at the Durham hospital, however, until a second test within the next 72 hours can confirm the results.

Duke Hospital's chief medical officer, Dr. Lisa Pickett, said the initial test is a good sign but that, although the results are negative, there is a window of time where the Ebola virus "grows" in the bloodstream and that early on, concentrations can be very low.

"Sometimes, in very early stages, with only a few symptoms, there will not be enough virus in the blood to turn the test positive," Pickett said. "Then later, as there's more and more virus in the blood, there would be enough to turn the test positive and then, likely at that point, to give the patient more symptoms."

A second test on Wednesday, if negative, will be enough to rule out Ebola, Pickett said.

Until that time, the protocol remains in place and the patient in isolation.

"We are confident," she said, "but we are continuing to treat him as though he has Ebola, with all isolation and security practices around him, to be sure that our staff and the community are safe and that the patient receives good care."

The patient, Pickett said, is being quarantined in in a special unit at the hospital – an entire wing of a floor – and has had direct contact with about a dozen staff members.

Those employees, she said, have employed a "buddy system," where they watch each other put on and remove protective gear to help safeguard against the possible risk of exposure.

Pickett said her staff was putting into practice a protocol that they had practiced just days ago.

"Each person who interacts with this patient has been trained for four hours from Duke University personnel who are used to dealing with biohazards on a daily basis," she said. Staffers will have the option of staying in isolation at the hospital if they are uncomfortable going home.

Wos said Sunday that the state has been preparing for months and is ready for potential Ebola cases.

"Today, this intensive preparation is being put to use," she said.

State epidemiologist Dr. Megan Davies said the patient had been without fever since arrival at Duke and had not developed any other symptoms that would be consistent with Ebola.

She reiterated that the patient had no symptoms and would not have been contagious during either the plane or bus ride, therefore the CDC is not worried about contacting those who might have traveled those routes.

The person – who had no known exposure to Ebola – measured a temperature of 101.9 degrees Sunday night upon arrival in Person County and called the CDC. The person was given a thermometer at Newark airport, a now-standard procedure for flights arriving from counties where Ebola is present.

Health experts say that Ebola is contagious only after the onset of symptoms and is spread through direct, unprotected contact with the bodily fluids of an infected person. It is not spread through air, water, food or proximity.

Other patients at the hospital, staff and those who work nearby seem to have gotten that message.

"It's not a big deal," said patient Joan King. "I trust this place. If he had to come to a place and be treated, this is a good place."

Rich D’Angiolillo, who works near the hospital, agreed.

"Duke – they’ll take care of people very, very well," he said. "Probably the people who are most at risk are the caretakers."