On Monday, 16 American cruise ship passengers arrived at the University of Nebraska Medical Center; 15 are in the quarantine unit and one person who tested positive is in the biocontainment unit.

Three of those passengers now in Nebraska are residents of New York, according to New York state Health Commissioner Dr. James McDonald.

“One passenger is from New York City, while the other two are residents of Orange County and Westchester County. All three are expected to be subject to a 42-day monitoring period," McDonald said in a statement.

“It is important to emphasize that there is no immediate risk to the public,” McDonald added.

Emory University Hospital said that, of the two cruise ship passengers now at its Serious Communicable Diseases Unit, one is symptomatic and is “receiving care in Emory’s biocontainment unit.”

The other passenger is asymptomatic and is “undergoing evaluation and monitoring.”

These two passengers are a couple, officials said earlier on Monday.

There are likely 10 total hantavirus cases, including one American and one French passenger who tested positive after disembarking the ship, officials said.

Of the 18 U.S. residents who were repatriated, 16 are in Nebraska: the one who tested positive is in biocontainment and the 15 who did not test positive are in quarantine, officials said. The other two U.S. residents are in Atlanta, officials said.

Additionally, nine U.S. cruise ship passengers who disembarked prior to the outbreak being discovered are being monitored by state health departments, officials said. Two are in Texas, two are in Georgia, one is in Virginia, one is in Arizona and one is in California.

Another two Americans who were exposed during air travel are in New Jersey, officials said.

-ABC News’ Youri Benadjaoud

Fifteen passengers were welcomed to the University of Nebraska Medical Center’s quarantine unit Monday morning and one person who tested positive is in the biocontainment unit, according to officials.

The quarantine unit is more like a hotel, while the biocontainment unit is patient-based care, more like a hospital, officials said.

The 15 passengers at the quarantine unit are in “good spirits,” the unit’s medical director, Dr. Mike Waldman, said.

“We’ve been doing symptom monitoring, as well as temperature checks," he said. "Everyone here is asymptomatic and ... do not have a temperature at this time. They're all resting now and we'll do further assessments later in the day, once they've had a chance to sleep."

The one person in the biocontainment unit is doing well and does not have symptoms, but is “very tired” after a “really long journey,” officials said.

The 15 in the quarantine unit will have the option to stay in Nebraska at the quarantine center for the entire 42-day monitoring period, or go home to monitor symptoms, in coordination with their state and local health departments, officials said. This will be based on whether they develop symptoms, have a support structure at home to quarantine and can contact their health department, officials said.

Besides the 16 cruise ship passengers in Nebraska, two cruise ship passengers -- who are a couple -- were flown to Atlanta “for further assessment and care," officials said. At least one of the two in Atlanta had symptoms, officials said.

The two patients in Atlanta "are under medical evaluation" at Emory University’s Serious Communicable Diseases Unit, officials said, noting that their transfer there was "contingency planning."

"That means, if we're on it, since there was symptoms involved, they want to make sure that if they turn out to actually have the hantavirus, that it makes sure that the biocontainment unit here that provides medical care doesn't take up too much space, in case it's needed by the other passengers who are currently here in the more residential section," officials said.

The Georgia Department of Public Health said, "There is no risk to the public at this time. ... DPH is also remaining actively in communication with the CDC and other partners and will continue to do so for as long as necessary as we monitor each development in the coming days and weeks.”

Jake Rosmarin, one of the American cruise patients currently quarantining in Nebraska, provided an update on his Instagram page Wednesday.

On his third day of quarantine at the National Quarantine Unit, Rosmarin showed off his thermometer used to take his temperature, his breakfast and his daily routine.

"One thing I really want to emphasize is how kind everyone here has been. The staff truly want to make sure we are as comfortable and cared for as possible during all of this. They even asked me what Starbucks I’d want and said they were hopefully going to get one delivered to me again today," he wrote in the post.

-ABC News' Matt Foster