A deadly hantavirus outbreak aboard a cruise ship in the Atlantic Ocean has triggered a coordinated international response involving the WHO, CDC, and health authorities across more than a dozen countries. Three people are dead. Eleven cases have been confirmed or suspected. American passengers have been airlifted to biocontainment units in Nebraska and Atlanta.
But what exactly is the Andes virus, how is it spreading on a cruise ship, and should you be worried?
Here is everything you need to know.
What Ship Is at the Center of the Outbreak?
The cruise ship at the center of the outbreak is the MV Hondius, a Dutch-flagged expedition vessel operated by Oceanwide Expeditions. The ship departed from Ushuaia, Argentina, on April 1, 2026, carrying 147 people: 86 passengers and 61 crew members from 23 different countries.
The voyage took the ship across the South Atlantic, stopping at several remote locations including Antarctica, South Georgia Island, Tristan da Cunha, Saint Helena, and Ascension Island before heading north toward the Canary Islands.
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Illness onset among passengers occurred between April 6 and April 28, 2026. By the time the WHO was notified on May 2, three people had already died.
What Is the Andes Virus and How Is It Different from Regular Hantavirus?
This is the most important question for understanding why this outbreak is being taken so seriously.
Hantavirus is a group of viruses typically carried by rodents and spread to humans through contact with infected urine, feces, or saliva. In the United States, the most common strain is the Sin Nombre virus, responsible for Hantavirus Pulmonary Syndrome (HPS), which is acquired by breathing in dust contaminated with infected rodent droppings. Critically, the US strain is not spread from person to person.
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The Andes virus is different. It is primarily carried by the long-tailed pygmy rice rat found in South America, particularly in Argentina and Chile. What makes the Andes virus uniquely alarming among hantavirus strains is that it is the only hantavirus known to spread from human to human, not just from rodents to humans. That is the reason health authorities are treating this outbreak differently from a standard hantavirus case.
The WHO has confirmed that the Andes virus is responsible for the MV Hondius outbreak. The current working hypothesis is that one or more passengers were first exposed to the virus on land in South America before boarding the ship on April 1, and that the virus then spread between passengers and crew during the voyage.
How Many People Have Been Infected and How Many Have Died?
As of May 14, 2026, there are 11 cases of hantavirus linked to the MV Hondius outbreak, including three deaths. That puts the current case fatality ratio at approximately 27%, according to the WHO.
Of the 11 cases, the breakdown is as follows:
- Three confirmed deaths
- One patient who was critically ill and hospitalized in South Africa
- Additional confirmed and suspected cases among passengers and crew who have since been evacuated and repatriated
The WHO currently assesses the global public health risk from this outbreak as low, with the caveat that investigations are still ongoing.
Where Are the American Passengers Now?
The CDC has been coordinating the repatriation of American passengers from the MV Hondius since early May. Eighteen American passengers have been brought back to the United States and are being monitored at two specialized facilities:
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- Nebraska Biocontainment Unit at the University of Nebraska Medical Center in Omaha, which is handling 16 of the 18 returnees. All individuals in Nebraska are reported to be asymptomatic as of the latest update.
- Emory University Hospital in Atlanta, which is monitoring two additional passengers, one of whom was experiencing symptoms at time of admission.
One passenger, Dr. Stephen Kornfeld, had initially tested “faintly positive” for hantavirus but has since tested negative and been moved out of the biocontainment unit, according to CNN.
The CDC sent a team to meet the ship in the Canary Islands on May 7 to assess exposure risk among US passengers before their repatriation. Individual monitoring plans, potentially lasting up to 42 days, are being created for each returning American.
What Are the Symptoms of Andes Virus Hantavirus?
Symptoms of Andes virus infection typically follow a pattern that mirrors what was seen among MV Hondius passengers:
Early stage: Fever, fatigue, muscle aches, and gastrointestinal symptoms including nausea, vomiting, and abdominal pain. This stage can last several days and is often mistaken for a common illness.
Late stage: Rapid progression to pneumonia, fluid in the lungs, and in severe cases, Acute Respiratory Distress Syndrome (ARDS) and shock. This stage can develop within days of the early symptoms appearing and can be fatal if not treated quickly.
There is no licensed specific antiviral treatment for hantavirus infection. Treatment is entirely supportive, meaning doctors manage symptoms and complications, particularly respiratory failure, using intensive care measures including mechanical ventilation.
Is There a Risk of Spread to the United States?
The CDC has classified its hantavirus response as Level 3, the agency’s lowest emergency classification, and has stated the risk to the US public is “extremely low.” The agency has, however, issued a Health Alert Network advisory to clinicians and health departments asking them to be aware of the potential for imported cases among travelers who may have been on or near the ship.
Separately, Illinois state health officials announced on May 12 that they are investigating a potential hantavirus case in an Illinois resident that is entirely unrelated to the MV Hondius outbreak. That individual lives in Winnebago County, has not traveled internationally, and is believed to have been exposed while cleaning a home with rodent droppings. Critically, the Illinois case involves a North American strain that does not spread from person to person, making it a routine hantavirus exposure rather than an outbreak concern.
How Did the Virus Get on the Cruise Ship?
The WHO’s current working hypothesis, as reported by US News and World Report, is that the initial exposure happened on land in South America before the ship departed, and that human-to-human transmission then occurred during the voyage.
Cases 1 and 2 in the WHO’s outbreak report, a couple from the Netherlands, had traveled in Argentina before boarding the MV Hondius on April 1. The first passenger is believed to have developed symptoms around April 6. His wife went ashore at Saint Helena on April 24, flew to Johannesburg on April 25, and died upon arrival at a hospital there on April 26. PCR testing later confirmed she had Andes hantavirus.
The fact that a ship’s doctor also tested positive for Andes virus and was evacuated to the Netherlands in stable condition further supports the human-to-human transmission theory, since medical staff would typically not have the same wildlife exposure as expedition passengers
What Should You Do If You Were on the MV Hondius or Near Affected Passengers?
The CDC has issued interim guidance for people with potential exposure to Andes virus. Key points:
- Monitor for symptoms including fever, muscle aches, fatigue, and any respiratory symptoms for up to 42 days after potential exposure.
- Contact your local health department if you were a passenger or crew member on the MV Hondius or had close contact with a confirmed case.
- Do not wait for symptoms to worsen before seeking medical care. Andes virus can progress rapidly.
- Contact the CDC at cdc.gov/hantavirus or submit a report through your state health department.
The full CDC guidance for clinicians and public health departments is available at the CDC Health Alert Network page.
Key Takeaways
- A hantavirus outbreak aboard the MV Hondius cruise ship has killed three people and infected 11, with a case fatality rate of approximately 27%.
- The strain involved is the Andes virus, the only known hantavirus that can spread from human to human, not just from rodents to humans.
- The WHO’s working hypothesis is that passengers were first exposed on land in South America before boarding, with human-to-human transmission occurring during the voyage.
- 18 American passengers have been repatriated to specialized facilities in Nebraska and Atlanta and are being monitored for up to 42 days.
- The CDC and WHO both assess the risk to the general public as very low, but have issued alerts to healthcare providers to watch for imported cases.
- There is no licensed antiviral treatment for hantavirus. Care is entirely supportive, making early detection and hospitalization critical.
