HANTAVIRUS AND THE 2026 MV HONDIUS OUTBREAK

By Fawunmi Elizabeth

​Hantaviruses are a family of zoonotic viruses naturally carried by rodents and are capable of causing severe, sometimes fatal illnesses in humans. Infection commonly occurs when individuals inhale tiny airborne particles contaminated with the urine, droppings, or saliva of infected rodents.

​Most hantavirus strains are not transmitted from person to person. However, the Andes virus, found mainly in South America, is a notable exception because it has documented cases of limited human-to-human transmission. This characteristic became a major concern during the 2026 outbreak linked to the Dutch-flagged expedition cruise ship MV Hondius, operated by Oceanwide Expeditions.

​The ship departed from Ushuaia, Argentina, on April 1, 2026, for a voyage through Antarctica and remote South Atlantic islands. Between April and May 2026, a cluster of hantavirus cases emerged among passengers and crew, with the index case showing symptoms as early as April 6. As of May 18, 2026, health authorities have identified nine confirmed cases linked to the ship, along with three suspected cases. The outbreak has resulted in the deaths of three passengers. The strain involved has been confirmed as the Andes hantavirus.

​International contact tracing efforts are ongoing for passengers who disembarked earlier, with health authorities recommending a 42-day monitoring period to account for the incubation range. The World Health Organization (WHO) has emphasized that this is a contained, ship-associated outbreak with low risk to the general public and is “not the start of a pandemic.”

​Hantaviruses cause two major clinical syndromes. The first is Hantavirus Pulmonary Syndrome (HPS), also called Cardiopulmonary Syndrome, which is more common with New World viruses such as Andes and Sin Nombre. HPS begins with flu-like symptoms but can rapidly progress to severe respiratory distress, fluid accumulation in the lungs, low blood pressure, and cardiogenic shock. The second is Hemorrhagic Fever with Renal Syndrome (HFRS), which is more common with Old World hantaviruses and mainly affects the kidneys, sometimes causing bleeding complications.

​The incubation period generally ranges from one to eight weeks, most often two to four weeks. Early symptoms (prodromal phase) often include fever, chills, fatigue, headache, dizziness, muscle aches, nausea, vomiting, and abdominal pain. In severe HPS cases, symptoms can worsen rapidly to coughing, shortness of breath, and life-threatening pulmonary edema. Fatality rates for severe HPS are estimated at approximately 35–40 percent or higher without intensive medical care.

​Preventing hantavirus infection primarily involves reducing contact with rodents. Key measures include sealing entry points in buildings, using traps, properly storing food, and removing attractants. When cleaning potentially contaminated areas, wear gloves and an N95 mask and use wet cleaning methods. For the Andes virus, authorities also recommend good hand hygiene and avoiding very close, prolonged contact with symptomatic individuals. The risk of infection remains highest in areas with large rodent populations, particularly during cleaning of rodent-infested spaces, farming, camping, or entering poorly ventilated buildings, where seasonal, environmental, and ecological changes that influence rodent populations can affect disease patterns.

​There is no specific antiviral cure. Treatment is entirely supportive, often requiring ICU care with oxygen, mechanical ventilation, ECMO, fluid management, and vasopressors. Early intensive care greatly improves survival. Recovery can be prolonged.