The American passenger who tested positive for hantavirus will be transported to the Nebraska Biocontainment Unit, according to Nebraska Medicine, which hosts the facility.

The individual does not have any symptoms and was separated from other passengers during the flight through biocontainment measures. They will be receiving a follow-up test, Nebraska Medicine said.

The remaining passengers will go to the National Quarantine Unit for assessment and monitoring.

The Department of Health and Human Services released a statement on Sunday saying one American has tested positive for hantavirus as the plane with 18 MV Hondius passengers is headed to the U.S.

Two of the passengers on the plane are traveling in the aircraft's biocontainment units "out of an abundance of caution," according to HHS.

The agency said that of the two, one passenger currently has mild symptoms and the other has tested PCR positive for the virus.

The plane is first going to the ASPR Regional Emerging Special Pathogen Treatment Center (RESPTC) at the University of Nebraska Medical Center before taking the passenger with mild symptoms to a second RESPTC, according to HHS.

"Upon arrival at each facility, each individual will undergo clinical assessment and receive appropriate care and support based on their condition," HHS said.

The plane carrying 18 passengers, including 17 Americans and one British national who is a U.S. resident, that disembarked from the MV Hondius has departed Spain and is headed back to the United States.

The American passengers who disembarked from the MV Hondius have arrived at Tenerife airport in the Canary Islands.

A total 18 people will be on the American repatriation flight, including the 17 Americans and one British national who is a resident of the U.S., the Spanish minister of health told ABC News.

-ABC News' Maggie Rulli

The hantavirus outbreak aboard the MV Hondius "is on the end of its run right now," a top infectious disease expert told ABC News "This Week" Sunday.

"The good news is that, in a sense, it is hantavirus and not another coronavirus or influenza virus. This is one that has very limited ability to be transmitted person to person. In fact, it's a rare exception," Dr. Michael Osterholm, director of the University of Minnesota's Center for Infectious Disease Research and Policy (CIDRAP), told ABC News' Martha Raddatz. "And so we have no question about the fact that this really is on the end of its run right now."

There are about 30 cases of hantavirus a year in the U.S. on average, and "they mostly occur west of the Mississippi" – about 96%, Osterholm said, due to a specific mouse that lives in that region. He also said that person-to-person transmission of the hantavirus strain in question is "a very rare exception," and only occurs when someone is exhibiting symptoms of the virus.

"Right now, you can manage the individuals who have been exposed very simply by asking them twice a day, 'are you experiencing any kind of a fever?' And then take the temperature: 'Do you have any symptoms?' If somebody is identified right at that point, you can put basically an N95 mask on and stop all transmission," Osterholm said.

"So this is why we don't need this high-tech, you know, containment facilities, et cetera, to monitor these people. We can monitor them very simply," Osterholm added, explaining why quarantining returning Americans isn't necessary.

"I have complete confidence that we will have good compliance here," Osterholm said of monitoring passengers who are returning. "And I think within days, this will no longer be a story."

-ABC News' Quinn Scanlan