⁠Hantavirus Outbreak 2026: Total Cases, Symptoms, Precautions

Hantavirus Outbreak 2026

The MV Hondius Andes Hantavirus Outbreak

A deadly cluster of Andes hantavirus infections aboard a Dutch expedition cruise ship has triggered a global health response, spanning 23 countries, three confirmed deaths, and a 42-day quarantine for hundreds of passengers and crew.

By Health Desk  ·  Sources: WHO · CDC · ECDC · NEJM

What Is Hantavirus — and Why Is the Andes Strain Different?

Most hantavirus strains do not spread between people. The Andes virus is a rare and alarming exception.

Hantaviruses are a family of RNA viruses carried primarily by rodents. Humans typically become infected through contact with the urine, droppings, or saliva of infected animals — or by inhaling airborne particles contaminated with these materials. There are more than 50 known hantavirus species, but very few cause serious disease in humans.

The Andes virus (ANDV) is endemic to the Andes mountain regions of Argentina and Chile. It is classified as a Category A bioterrorism agent by the U.S. CDC — not because of any intentional threat, but because of its potential for serious illness and its ability, uniquely among all hantavirus strains, to spread directly from one person to another. This person-to-person transmission, most likely through respiratory droplets in cases of sustained close contact, is what makes the 2026 MV Hondius outbreak especially significant from a global public health standpoint.

In humans, the Andes virus typically causes Hantavirus Pulmonary Syndrome (HPS) — a severe, rapidly progressing disease affecting the lungs and cardiovascular system. Historical outbreaks have recorded case fatality rates of 20 to 40 percent, making it one of the deadliest viral infections currently circulating in the Americas.

How Did the Outbreak Begin? The MV Hondius Story

A birdwatching trip to Patagonia may have been the origin of an international health emergency.

The MV Hondius is a Dutch-flagged polar expedition cruise ship operated by Oceanwide Expeditions. On April 1, 2026, it departed from Ushuaia, Argentina — the southernmost city in the world — carrying 86 passengers and 61 crew members from 23 different countries, bound for Antarctica and several remote South Atlantic islands.

Before boarding, the first two patients — a Dutch couple — had spent three months travelling through Argentina, Chile, and Uruguay on a birdwatching expedition. This route took them through areas where the long-tailed pygmy rice rat (Oligoryzomys longicaudatus), the primary reservoir rodent of the Andes virus, is known to be present. Investigators believe they were likely exposed to the virus during this overland journey, before they ever stepped aboard the ship.

The outbreak unfolds at sea

The first patient (Patient 1), a 70-year-old Dutch man, began showing symptoms as early as April 6 — just five days after departure. He developed fever, headache, abdominal pain, and diarrhea. His condition rapidly worsened into severe acute respiratory infection and respiratory failure. He died aboard the ship on April 11. At the time, no microbiological testing was performed, and his death was not immediately linked to a specific pathogen.

His partner (Patient 2) began showing similar symptoms around April 24, when the ship docked at Saint Helena to disembark his body. She attempted to travel home to the Netherlands via Johannesburg but was too ill to board her connecting flight. She died in a South African emergency room shortly after.

The alarm was formally raised when Patient 3 — medically evacuated from the ship to Ascension Island on April 27 — was transferred to a Johannesburg ICU. Samples from his case were sent to a South African laboratory, which returned a positive result for hantavirus. Sequencing of a pre-death sample from Patient 2 also confirmed Andes virus.

Timeline of key events

Hantavirus Symptoms 2026 — What to Watch For

Andes virus infection progresses in two phases. Early symptoms can easily be mistaken for influenza, which makes rapid clinical suspicion critical.

Incubation period

The Andes virus has an incubation period of one to seven weeks (typically two to four weeks). This long and variable window is precisely why the ECDC and WHO established a 42-day quarantine and monitoring period for all passengers and high-risk contacts — to capture even the latest-appearing cases before they can unknowingly spread the virus to others.

How Hantavirus Spreads — and Why This Outbreak Is Unusual

Under ordinary circumstances, hantavirus does not spread between humans. Infection occurs through:

• Inhalation — breathing aerosolised particles of rodent urine, droppings, or nesting material (the most common route)
• Direct contact — touching contaminated surfaces and then touching the mouth or nose
• Rodent bites — rarely, through a direct bite from an infected animal

The Andes virus departs from this pattern. Evidence from previous outbreaks in Argentina and Chile, and now from the MV Hondius cluster, strongly suggests that ANDV can spread between people in close, sustained contact — particularly through respiratory secretions. The ECDC’s threat assessment notes that airborne transmission is considered a possibility for the ship cluster, while noting that previous outbreaks involved household exposure, caregiving without PPE, and prolonged exposure in poorly ventilated settings.

Global Response and Current Situation

The MV Hondius outbreak has triggered one of the most coordinated international infectious disease responses in recent years. Key actions taken by authorities worldwide:

As of May 20, 2026, no new cases or deaths have been reported since the previous ECDC update. Former passengers are being monitored or quarantined in at least 14 countries, including Australia, Canada, France, Germany, the Netherlands, Singapore, South Africa, Spain, Switzerland, Turkey, and the United States.

Hantavirus Outbreak 2026 Precautions — How to Protect Yourself

The overall global risk remains very low. These precautions are most relevant for travellers to endemic regions and those with potential exposure histories.

Treatment — Is There a Cure?

There is currently no approved antiviral treatment or vaccine for Andes virus infection. Care is entirely supportive and focuses on:

• Mechanical ventilation and intensive respiratory support (the cornerstone of HPS management)
• Extracorporeal membrane oxygenation (ECMO) in the most severe cases
• Careful fluid management to reduce pulmonary oedema
• Vasopressors and inotropes to support blood pressure and cardiac function
• Monitoring for and treating secondary complications (kidney failure, coagulopathy)

Some clinical trials have investigated ribavirin (an antiviral used against other RNA viruses), but evidence for its efficacy against Andes virus remains limited. Several research programmes are underway to develop vaccines and specific antivirals using recombinant protein and mRNA platforms, but none has reached clinical approval. The best available intervention remains early intensive care support — which is why seeking emergency attention at the very first sign of respiratory deterioration is so critical.

Frequently Asked Questions

Can I catch hantavirus from another person in everyday settings?

For almost all hantavirus strains, no. The Andes virus is the one known exception — but even with ANDV, person-to-person transmission appears to require close, sustained contact, such as living in the same household, providing direct care without PPE, or spending prolonged time in a poorly ventilated, confined space with an infected person. Casual contact in public settings carries negligible risk.

I recently returned from Argentina or Chile. Should I be worried?

If you were not aboard MV Hondius and did not spend time in rodent-endemic rural or forested areas (particularly Patagonia, the Andes foothills, or the pampas), your risk is very low. If you did visit such areas and are now experiencing fever, muscle aches, and breathing difficulty, contact your doctor or go to an emergency department and clearly mention your travel history.

What is the 42-day quarantine, and why is it so long?

The Andes virus has an unusually long incubation period — anywhere from one to seven weeks (roughly 7–49 days). ECDC, in coordination with WHO and member states, set 42 days as the monitoring period to ensure that even the latest-appearing cases are detected before individuals can unknowingly expose others. Day 0 is defined as May 10, 2026. All those aboard the ship are required to self-quarantine and undergo daily symptom monitoring.

Is there a risk of a wider epidemic or pandemic?

Current assessment from WHO, CDC, and ECDC is that the risk of broader epidemic spread is low. The Andes virus does not spread through casual contact or via surfaces in the way respiratory viruses like influenza can. Previous ANDV outbreaks have remained geographically contained and only involved transmission in close-contact settings. Authorities continue to monitor the situation closely given the outbreak’s international reach.

Why is there no vaccine?

Hantavirus infections are relatively rare globally, and the Andes virus is geographically restricted under normal circumstances. This has historically limited commercial investment in vaccine development. Research is ongoing, including several candidate vaccines using recombinant protein and mRNA platforms, but none has yet completed the clinical trial process required for regulatory approval.

What should I do if I think I have been exposed?

Contact your local health authority or go to an emergency department immediately. Do not wait for symptoms to worsen. Inform the clinician of the specific nature of your exposure — travel to endemic areas, contact with rodents, or proximity to a confirmed MV Hondius case. If you are a former passenger, you should already be in contact with the public health authority in your country of residence.