A deadly hantavirus outbreak aboard a cruise ship has led health authorities around the world to monitor passengers who left the ship early for symptoms of the illness — including in the United States. And after the ship docked in the Canary Islands on May 10, more containment efforts began for remaining passengers and crew as they travel home on Sunday and Monday.

As of Sunday, none of the passengers on the ship were showing symptoms of hantavirus, Monica Garcia, Spain’s Minister of Health, said.

So far, three people, a married couple and a German national, have died in the outbreak. The World Health Organization said on May 8 that there are eight confirmed or suspected hantavirus cases linked to the cruise ship.

Several people the U.S. are also being monitored for possible hantavirus exposures and symptoms related to the cruise ship outbreak. After the 17 remaining Americans fly back to the U.S., scheduled for Monday, they will be placed in the National Quarantine Unit at the University of Nebraska Medical Center, according to a press release.

“We are prepared for situations exactly like this,” Dr. Michael Ash, CEO of Nebraska Medicine, said in a statement. “Our teams have trained for decades alongside federal and state partners to make sure we can safely provide care while protecting our staff and the broader community.”

After the ship reached its destination, WHO Director-General Tedros Adhanom Ghebreyesu told reporters, “Based on scientific assessment and based on evidence, the risk (to the public) is low.”

He added that people “shouldn’t be scared and they shouldn’t panic.”

Here’s what to know about the spread of the illness and where it’s being monitored in the United States.

The Latest on the Hantavirus Outbreak

The MV Hondius reached its destination, Tenerife in Spain’s Canary Islands, early Sunday, May 10, NBC News reported. The first set of passengers to fly home, about 14 Spaniards, left for Madrid shortly after leaving the ship.

All passengers will be kept separate from the public until their flights home, and when they arrive, many will be taken to isolation facilities, Dr. Maria Van Kerkhove, the WHO’s head of epidemic and pandemic preparedness, said. In this U.S., this will take place at the University of Nebraska Medical Center.

The WHO recommendation is that people be actively monitored for 42 days after they were last exposed to a confirmed hantavirus case.

Passengers have been leaving the ship in personal protective equipment and in small groups spaced apart to minimize potential exposure risk, even though none are currently showing symptoms, Dr. Boris Pavlin, a WHO medical epidemiologist, told NBC News.

“This is not Covid,” he added. “In Covid, we’ve all been traumatized by how people you didn’t even think were sick were already spreading it, (but) we have no reason to believe that that’s happening here.”

The outbreak among the eight confirmed or suspected people is believed to be the rare Andes strain of the virus, which is the only type of hantavirus known to spread from human to human. Hantavirus is mainly spread from rodents to humans.

The ship had about 150 passengers and crew at the start of its journey, but there were 30 passengers who disembarked the ship in Saint Helena on April 24, according to a press update released May 7 by Oceanwide Expeditions, the operator of the cruise. One of the passengers was an individual who died April 11 while the ship was at sea, according to a timeline provided by the company.

Passengers who left the ship prior to the May 10 docking are also being monitored in Spain, Switzerland, South Africa, the United Kingdom, the Netherlands and the United State, authorities in those countries said.

The cruise originally left from Ushaia, Argentina, on April 1 and made a stop at Tristan de Cunha on April 15 and then St. Helena on April 24, according to Oceanwide Expeditions.

Map of Hantavirus Cruise Ship Exposures in the US

Several U.S. nationals who disembarked the cruise ship and traveled home are in five states, per NBC News reporting: Texas, Georgia, Arizona, Virginia and California.

None of these patients have shown symptoms or have tested positive for the hantavirus, authorities said.

The New Jersey Department of Health has also said it is monitoring two residents who were potentially exposed to someone with hantavirus from the Hondius cruise ship. The potential exposure occurred during air travel, as the residents were not passengers themselves. They are being monitored as a precaution, and neither is showing symptoms.

“At this time, the risk to the general public in New Jersey remains very low,” the NJDOH said. “No current hantavirus cases have been identified in the state, and there is no history of a confirmed hantavirus case reported in New Jersey.”

Is Hantavirus in the US?

While several passengers from the cruise ship with the hantavirus outbreak have already returned to the U.S., none have shown symptoms or tested positive for the virus, according to local authorities. Their identities have not been released.

Once the remaining Americans from the ship return stateside, they will be quarantined in the National Quarantine Unit at University of Nebraska Medical Center.

The current risk to the American public from the hantavirus outbreak is “extremely low,” the U.S. Centers for Disease Control and Prevention said in a May 7 statement. “We urge all Americans aboard the ship to follow the guidance of health officials as we work to bring you home safely,” the agency added.

While hantaviruses are found in the U.S., the Andes strain implicated in the outbreak is linked to rodents living in South America, according to the CDC. The rodents that carry the Andes virus have not been found in the U.S., per the CDC.

Hantavirus cases have been previously reported in the U.S. over the years, according to the CDC. Since the CDC began testing for it in 1993 following an outbreak in the Southwest, there were 890 total cases reported through 2023.

A majority of them were located in states in the West and Southwest, with 62% of the cases being contracted by men, per the CDC.

Hantavirus was the cause of death of Betsy Arakawa, the late actor Gene Hackman’s wife.

What Are Symptoms of Hantavirus?

Hantavirus can cause two distinct types of disease, depending on the strain.

The Andes strain, along with other hantaviruses in the Americas, causes hantavirus pulmonary syndrome (HPS), a severe and often fatal respiratory illness, according to the CDC.

Symptoms of HCPS can take four to 42 days to appear after exposure, per the CDC.

Early symptoms of HPS include:

FeverChillsFatigueMuscle achesHeadacheDiarrhea, vomiting or abdominal pain

After four to 10 days, these flu-like HPS symptoms progress to:

Coughing fitsBreathing difficultiesFluid in the lungsRespiratory failure

The sick passengers aboard the MV Hondius mostly reported flu-like illness and gastrointestinal symptoms, according to the WHO. Some remained mild, and others progressed rapidly to respiratory distress or pneumonia.