Clinical Insights Around the Hantavirus and the Cruise Ship Outbreak

As of yesterday, the World Health Organization (WHO) reported the cluster of hantavirus cases aboard the cruise ship, MV Hondius, had increased to 8 infections and remained at 3 deaths. Five of the cases have tested positive for the Andes virus, the only hantavirus species known for limited human-to-human transmission.¹ The ship started with 147 passengers and crew and is currently in the Atlantic Ocean, approximately 200 miles off the west African coast near Mauritania, sailing toward the Canary Islands.

Transmissibility

Most species of the hantavirus are transmitted from mice or rats to people through the animals’ urine or feces. Luis A. Marcos, MD associate professor of Medicine, director for the Infectious Diseases Fellowship Program at Stony Brook Medicine, points out this virus is not highly contagious when transmitted from person-to-person.

“The number of people that can be infected from one infected person is 1 to 2 people, whereas other respiratory viruses are much more contagious,” Marcos said. He points to COVID and measles being much more transmissible.

Back in 2017, Marcos and his colleagues treated a female patient from east Long Island with hantavirus, who eventually recovered.

“The transmission of person to person, is basically contact with saliva. It could be respiratory droplets, or airborne, but usually its the exchange of fluids or close contact,” Marcos said.

Marcos points out the incubation period is 4 to 8 weeks, and says it is likely there may be some more cases in this current cruise ship cluster, but mainly those who were in close contact with the infected individuals during the last 4 weeks.

He says that once infection control measures are in place, it is unlikely more people will become infected.

The 2 Disease Syndromes

Hantaviruses are responsible for 2 main disease syndromes. In the Western Hemisphere, including the United States, they cause hantavirus pulmonary syndrome (HPS).²

A second condition, hemorrhagic fever with renal syndrome (HFRS), includes a group of related illnesses caused by hantaviruses primarily found in Europe and Asia. However, Seoul virus—a hantavirus that leads to HFRS—has a global presence and is also found in the United States.²

The Andes Species and Risk Factors for Contraction

It is important to note, the Andes virus is typically seen in South America, which is where this cruise started.³ It is mostly seen in Argentina, Brazil, and Chile, especially in the Patagonia region of the continent.³ In Argentina, there are a reported 100–200 cases annually. The Andes virus is the most common cause of HPS in South America.³

In regards to this current cluster onboard the ship, Marcos points out the first 2 people infected were a couple from Argentina, who were traveling in rural areas of that country.

“They were really exposed to the remote, rural areas where most likely, mice were there with the virus.”

While, the hantavirus does exist here in the US, it is typically found in the southwest and most commonly transmitted by the deer mouse. In terms of HPS, Marcos points out how people are more likely to contract the virus.

“The classic example is the person who goes camping, hiking in the southwest. They start doing the tent cleaning, and they found some features of mice. And once you vacuum, or you are cleaning, then the virus goes into the air, and you inhale the virus,” Marcos said.

In terms of prevention, Marcos says in those circumstances people should use masks and gloves when cleaning.

Treatment

Right now there are no FDA approved antivirals or therapies for the virus, and Marcos points out patients are given supportive care.

“If you have a lot of fluid in the lungs and you need help to breathe, they put you on the ventilator. If your platelets are low and you are bleeding, then they will transfuse your platelets. In about a week or so, this storm of the virus will go away, and then you will recover.”

References
1. WHO’s response to hantavirus cases linked to a cruise ship.WHO. May 7, 2026. Accessed May 7, 2026.
https://www.who.int/news/item/07-05-2026-who-s-response-to-hantavirus-cases-linked-to-a-cruise-ship
2.About Hantavirus. CDC. May 13, 2024. Accessed May 4, 2026.
https://www.cdc.gov/hantavirus/about/index.html
3. Andes virus. Wikipedia. Accessed May 8, 2026.
https://en.wikipedia.org/wiki/Andes_virus