Hantavirus on the High Seas: What the MV Hondius Outbreak Tells Us About This Silent Threat

May 12, 2026

A luxury expedition cruise through Antarctica and the South Atlantic has become the center of an international health emergency. The Dutch-flagged vessel MV Hondius, carrying around 147 passengers and crew of 23 nationalities, is now linked to one of the most alarming hantavirus outbreaks in recent memory, prompting emergency evacuations, international contact tracing, and a coordinated response from the WHO, CDC, and ECDC.

Three people have died. Several others have been hospitalized across South Africa, the Netherlands, Germany, Spain, Switzerland, and Saint Helena. Passengers have been flown home on military and government aircraft after the ship docked in Tenerife, Canary Islands, on May 10. Some returning travelers are now in quarantine for up to 45 days.

So what exactly is hantavirus, how does it spread, and what can we do to protect ourselves? Here’s what you need to know.

What Is Hantavirus?

Hantavirus is a family of viruses carried primarily by rodents. When humans come into contact with infected animals,  or their urine, droppings, or saliva,  they can become seriously ill. The disease is rare, but it can be deadly.

In the Americas, hantavirus causes Hantavirus Pulmonary Syndrome (HPS), a severe respiratory illness. In Europe and Asia, a different set of strains cause Haemorrhagic Fever with Renal Syndrome (HFRS), which primarily affects the kidneys.

The strain responsible for the MV Hondius outbreak is the Andes virus (ANDV)  a particularly concerning type found mainly in South America, especially Argentina and Chile. It is notable for a grim distinction: it is the only known hantavirus that can spread from person to person, even if such transmission remains rare and typically requires close, prolonged contact.

There is currently no specific antiviral treatment for hantavirus. Supportive care  oxygen, fluids, and intensive monitoring  is the best available option, making early detection critical.

The MV Hondius Outbreak: What Happened

The ship departed from Ushuaia, Argentina — one of the southernmost cities in the world — on April 1, 2026, bound for Antarctica and several remote South Atlantic islands. Cases 1 and 2 had visited South America, including Argentina, before boarding, likely exposing them to Andes virus in an endemic area.

The first passenger developed fever, headache, and mild diarrhoea on April 6 while at sea. By April 11, he had developed acute respiratory distress and died on board. His wife, a close contact, began showing gastrointestinal symptoms when she disembarked at Saint Helena on April 24. She deteriorated rapidly during a flight to Johannesburg and died upon arrival at the emergency department on April 26. She was later confirmed by PCR to have hantavirus infection.

On May 2, 2026, WHO was formally notified. By May 8, eight cases had been identified, six confirmed and two suspected, with three deaths. The CDC has classified the outbreak as a Level 3 emergency response.

What makes this outbreak particularly unusual is the evidence of human-to-human transmission on board the ship, something documented previously with Andes virus but considered very rare. The confined, enclosed environment of a cruise ship likely played a significant role.

Symptoms to Watch For 

Symptoms of HPS caused by Andes virus typically appear 4 to 42 days after exposure. The disease progresses in two stages:

Early stage (1–5 days): Fever, fatigue, muscle aches (especially in the thighs, hips, back, and shoulders), headache, dizziness, chills, and sometimes nausea, vomiting, or diarrhoea. These symptoms can easily be mistaken for flu.

Late stage (days 4–10): A sudden onset of coughing and shortness of breath, as the lungs fill with fluid. This can progress rapidly to acute respiratory distress syndrome (ARDS) and shock. Approximately 38% of people who develop respiratory symptoms may die from the disease.

If you have had potential exposure and develop any of these symptoms, seek medical attention immediately and inform the healthcare provider of your possible contact with hantavirus.

How Hantavirus Spreads – and How Andes Virus Is Different

For most hantaviruses, the route of infection is straightforward: rodents (especially deer mice and other wild rodents) carry the virus without getting sick themselves. Humans get infected by:

·         Breathing in dust contaminated with rodent urine, droppings, or nesting materials (the most common route)

·         Touching contaminated surfaces and then touching the mouth, nose, or eyes

·         Rarely, through rodent bites

The Andes virus adds an extra layer of concern: it can also pass from person to person, though this typically requires close and prolonged contact. According to the CDC, this includes:

·         Direct physical contact with a symptomatic person

·         Prolonged time in close or enclosed spaces with an infected individual

·         Exposure to saliva, respiratory secretions, or other body fluids (such as kissing, sharing utensils, or handling contaminated bedding)

Importantly, people are generally only infectious while they have symptoms. The virus does not appear to spread easily in casual, brief social contact.

Safety Measures: How to Protect Yourself 

If you are in or have recently visited South America (especially Argentina or Chile):

·         Avoid contact with wild rodents and their habitats (burrows, nests, droppings)

·         Do not handle dead rodents without proper protective equipment

·         When camping or hiking in endemic areas, avoid sleeping on bare ground; use tents with floors and keep food in sealed containers

·         Air out enclosed spaces (cabins, sheds) before entering, especially after periods of disuse

·         Use gloves and a mask when cleaning areas that may have rodent contamination

If you were on the MV Hondius or had close contact with a confirmed case:

·         Monitor yourself for symptoms for up to 42 days from your last potential exposure

·         Follow quarantine or self-isolation guidance from your national health authority

·         Contact a doctor immediately if you develop fever, fatigue, muscle aches, or breathing difficulties  and tell them about your potential exposure

·         Do not share utensils, bedding, or personal items with symptomatic individuals

For the general public:

·         Wash hands frequently with soap and water

·         Practice respiratory etiquette (cover coughs and sneezes)

·         Maintain physical distance from anyone who is symptomatic

·         The overall risk to the general public remains very low, according to both WHO and CDC

The Bigger Picture

The MV Hondius outbreak is a reminder of how quickly an unknown or forgotten pathogen can enter the spotlight  and how interconnected our world is. Passengers from 23 nationalities were on board. Cases have now appeared in six countries across two continents. A single flight from Saint Helena to Johannesburg became a contact tracing event involving dozens of people.

The good news: WHO currently assesses the risk to the global population as low. Andes virus does not spread easily, there is no evidence of sustained community transmission, and health authorities around the world have moved quickly. The bad news: there is no vaccine and no cure  only early detection and supportive care.

Stay informed, stay calm, and if you have any reason to believe you were exposed, don’t wait. Contact a medical professional.

WHO Disease Outbreak Notice: https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON599

CDC Health Advisory: https://www.cdc.gov/han/php/notices/han00528.html

ECDC Risk Assessment: https://www.ecdc.europa.eu/en/publications-data/hantavirus-associated-cluster-illness-cruise-ship-ecdc-assessment-and 

Source: Hantavirus on the High Seas: What the MV Hondius Outbreak Tells Us About This Silent Threat – Scents of Science