GENEVA — May 7, 2026 : International health authorities are investigating a cluster of hantavirus infections identified among passengers and crew aboard the Dutch-flagged expedition cruise vessel MV Hondius, after seven individuals developed severe respiratory illness during a voyage spanning South America, Antarctica, and the South Atlantic.
According to information released by the World Health Organization (WHO), the vessel departed Ushuaia, Argentina, on 1 April 2026 and later transited through Antarctica, South Georgia, and several remote islands while en route to the Canary Islands. The ship is currently anchored off the coast of Cape Verde as investigations and medical response operations continue.
Among the 147 passengers and crew members on board, seven people became ill between 6 and 28 April 2026. Of those affected, three individuals have died, one remains in critical condition, and three others are experiencing mild symptoms. Several patients have been medically evacuated for treatment at shore-based facilities.
Health officials said the illnesses initially presented with fever and gastrointestinal symptoms before progressing rapidly in severe cases to pneumonia, acute respiratory distress syndrome (ARDS), shock, and respiratory failure. Laboratory testing has confirmed hantavirus infection in two patients, while five additional cases remain classified as suspected infections pending further diagnostic analysis.
The WHO stated that it is working in coordination with health authorities from the countries involved, as well as with the ship’s operator, Oceanwide Expeditions, to provide medical guidance, epidemiological support, and information to passengers and crew. Based on currently available evidence and the known transmission characteristics of hantaviruses, the organization has assessed the overall risk to the global population as low.
WHO officials said the assessment could be revised as additional laboratory findings, contact tracing data, and environmental investigations become available. Public health teams are continuing to monitor the situation closely while implementing infection prevention measures aboard the vessel.
Investigators are examining several possible sources of exposure, including contact with rodents or contaminated environments during shore excursions in regions where hantaviruses are known to circulate naturally. Authorities are also reviewing passenger movement patterns, onboard interactions, and environmental conditions during the voyage.
Hantaviruses belong to the family Hantaviridae and are primarily carried by rodents, which act as natural reservoir hosts without typically showing signs of illness. Human infection most commonly occurs through inhalation of aerosolized viral particles from rodent urine, droppings, or saliva. Transmission may also occur through rodent bites, scratches, or contact with contaminated surfaces followed by touching the eyes, nose, or mouth.
The virus identified in the current cluster is reported to be the Andes virus, a hantavirus strain endemic to parts of South America. The Andes virus is the only hantavirus species for which limited person-to-person transmission has been documented. Health authorities noted, however, that such transmission is considered rare and generally requires prolonged close contact with an infected individual.
Medical experts classify hantavirus disease into two primary clinical syndromes. Old World hantaviruses, found mainly in Europe and Asia, are associated with hemorrhagic fever with renal syndrome (HFRS), which primarily affects the kidneys and can involve internal bleeding complications. New World hantaviruses, found in the Americas, are linked to hantavirus pulmonary syndrome (HPS), also referred to as hantavirus cardiopulmonary syndrome (HCPS), a severe respiratory illness characterized by rapid pulmonary deterioration.
Symptoms of hantavirus infection typically develop between one and eight weeks after exposure. Early manifestations often resemble influenza-like illness and include fever, fatigue, headaches, dizziness, chills, and muscle aches, particularly affecting the thighs, hips, and back. Gastrointestinal symptoms such as nausea, vomiting, diarrhea, and abdominal pain are also commonly reported.
In cases progressing to HPS, patients may develop coughing and severe shortness of breath within four to ten days after the onset of initial symptoms. Fluid accumulation in the lungs can rapidly lead to respiratory failure, low blood pressure, cardiovascular collapse, and shock. WHO data indicate that the fatality rate for HPS outbreaks has reached up to 40 percent in some documented cases.
There is currently no specific antiviral treatment or licensed vaccine for hantavirus infection. Clinical management primarily depends on early recognition of symptoms and intensive supportive care, including oxygen therapy, mechanical ventilation, hemodynamic monitoring, and fluid management in critical care settings.
Public health authorities emphasized that most hantavirus infections worldwide are linked to environmental exposure rather than sustained human-to-human transmission. Preventive measures focus largely on reducing contact with rodents and safely handling potentially contaminated areas.
Recommended precautions include sealing buildings to prevent rodent entry, storing food in rodent-proof containers, and avoiding dry sweeping or vacuuming of rodent droppings, which can aerosolize infectious particles. Health agencies advise using wet-cleaning methods with disinfectants or bleach solutions while wearing gloves and protective masks when cleaning areas suspected of rodent contamination.
The name “hantavirus” originates from the Hantan River, where the virus first gained international attention during the Korean War between 1951 and 1953. More than 3,000 United Nations troops developed hemorrhagic fever during that period. In 1978, scientists isolated the Hantaan virus from the striped field mouse (Apodemus agrarius) near the Hantan River, establishing the rodent link associated with hantavirus disease.
A separate milestone in hantavirus research occurred in 1993 during an outbreak in the Four Corners region of the southwestern United States, where an unexplained respiratory illness led researchers to identify hantavirus pulmonary syndrome caused by the Sin Nombre virus carried by deer mice.
WHO stated that contact tracing and onboard infection control measures remain active aboard the MV Hondius while investigations continue into the origin and transmission pathway of the current cluster. Health authorities are expected to release further updates as laboratory sequencing and epidemiological analysis progress.
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