MV Hondius: Hantavirus Aboard an Expedition Ship — What We Know

An outbreak of Andes hantavirus pulmonary syndrome linked to the expedition vessel MV Hondius has been confirmed, with cases spanning multiple countries and involving both passengers and crew.

What Happened

The MV Hondius, an expedition cruise ship, departed Ushuaia, Argentina in early April 2026 after completing a birdwatching tour of the Patagonian region. Shortly after departure, passengers and crew began developing febrile illness. Laboratory testing confirmed Andes hantavirus.

The index case — a Dutch passenger — had undertaken a four-month road trip through Chile, Uruguay and Argentina before boarding the ship. He and his wife had spent time birdwatching in areas where rodents have previously tested positive for hantavirus. He returned to Argentina from Uruguay just four days before embarkation.

Why This Outbreak Is Unique

The Andes virus is the only known hantavirus strain capable of human-to-human transmission. This was first documented in the 2018 Epuyén outbreak in Argentine Patagonia, where a rural worker transmitted the virus to contacts at a birthday party. The MV Hondius event represents the first documented ship-based Andes virus cluster.

IPC Implications for Healthcare Teams

Any healthcare facility receiving passengers or crew from the MV Hondius should apply droplet and contact precautions immediately and notify public health authorities before laboratory confirmation. The maximum incubation period for Andes hantavirus is 8 weeks. Patients presenting with febrile pneumonia of unclear etiology who traveled to South America in the past 8 weeks warrant an explicit travel and exposure history..

Understanding Andes Hantavirus Transmission

The Andes virus (ANDV) is unique among the more than 50 known hantavirus species. Every other hantavirus species requires direct exposure to infected rodent excreta — urine, feces, or saliva — for human infection. The Andes virus is the sole exception: it is the only hantavirus known to transmit directly from person to person.

This characteristic was first documented during the 2018 Epuyén outbreak in Chubut Province, Argentina, where a rural worker infected through rodent exposure subsequently transmitted the virus to close contacts at a birthday party. Of the 34 confirmed cases in that outbreak, 11 people died — a case fatality rate of approximately 32%.

The MV Hondius event represents the first documented ship-based Andes hantavirus cluster, and the first time that international cruise ship travel has been associated with hantavirus transmission. The index case's four-month road trip through Chile, Uruguay and Argentina — including birdwatching activities in areas with high rodent populations — likely created multiple opportunities for environmental exposure before embarkation.

Clinical Presentation and Diagnosis

Hantavirus Pulmonary Syndrome (HPS) presents in two phases. The prodromal phase — lasting 3 to 5 days — is clinically indistinguishable from influenza: fever, myalgia, headache, and fatigue. The cardiopulmonary phase follows abruptly, with rapid onset of pulmonary edema, hypoxemia, and in severe cases, cardiogenic shock. Progression from prodrome to respiratory failure can occur within 24 hours.

There is no approved antiviral treatment for HPS. Management is entirely supportive: mechanical ventilation, vasopressors, and careful fluid management in an intensive care unit. Early ICU admission before the cardiopulmonary phase is the most significant predictor of survival. The overall case fatality rate for Andes HPS ranges from 25% to 40%.