Four dozen people who had contact with the original Ebola patient in Dallas will complete a three-week watch period on Monday with no sign any of them has contracted the virus — a watershed in the fight to contain the disease in the United States.

“We are looking forward to Monday morning, when (the) first wave of 48 contacts and potential contacts will no longer be monitored for Ebola,” the city of Dallas said online.

It has been a tense three weeks since the patient, Thomas Eric Duncan, became the first person diagnosed with Ebola in the United States. Duncan, who had flown to Dallas from Liberia, was turned away from Texas Health Presbyterian Hospital on a first visit and admitted later.

Duncan died Oct. 8. Within days, two nurses who cared for him were diagnosed with Ebola themselves.

The virus has a 21-day incubation period. When a case is confirmed, health officials monitor anyone who had contact with that person for three weeks. If they don’t develop symptoms, they are cleared.

“We are so happy this is coming to an end, and we are so grateful that none of us has shown any sign of illness,” Louise Troh, Duncan’s fiancée and mother to the couple’s son, said late Sunday in a statement. Troh and three other people have been under quarantine — ordered by the government not to go out in public.

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“Our happiness is mixed with sadness at the same time,” she said. “We continue to mourn his (Duncan) loss and grieve the circumstances that led to his death, just at the time we thought we were facing a happy future together.”

After the isolation window closes, Troh and her children will spend a few more days at a temporary residence, then move to a new rental home in the Dallas area, said Dallas County Judge Clay Jenkins, who is heading the local Ebola response. Donors are paying for the family’s new home and hope to replace belongings that had to be destroyed in the cleanup process.

Troh’s daughter, Youngor Jallah, is among the group whose three-week watch period will end Sunday. Jallah, a nurse’s assistant who took Duncan’s vital signs, has stayed in an apartment she shares with her partner and their children, according to The Associated Press.

“I'm telling you, just to step outside will be so great,” she told The AP. “To hug my mom and grieve for Eric, not over the phone like we’ve been doing, but in the flesh.”

Troh’s family is among the first wave of people who had contact with an Ebola-infected person to finish the three weeks. Others, such as those who had contact with the two nurses, won't finish their quarantine for days.

More than 9,000 people in West Africa have been infected with Ebola, and half have died, sparking fears in the U.S. and elsewhere that the virus could spread.

Ebola spreads by close physical contact with the bodily fluids of someone who is infected and symptomatic. But despite the threat of the Ebola crisis growing exponentially in West Africa, Americans have little reason to fear the disease spreading here, experts told NBC’s “Meet the Press” on Sunday.

The Pentagon is fielding a 30-person expeditionary medical support team to provide immediate assistance to civilian health professionals in the U.S. if additional Ebola cases arise. The team will include 20 critical care nurses, five doctors trained in infectious disease and five trainers in infectious disease protocols, the Pentagon said in a statement.

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NBC's Sarah Dallof and The Associated Press contributed to this report.