When the MV Hondius cruise ship began reporting deaths in early May, the cause was unfamiliar to many. Soon, it was confirmed to be hantavirus, a virus typically carried by rodents, which managed to devastate a vessel carrying nearly 150 people.
Andes Strain: A Rare Human-to-Human Transmission
Days later, reports identified the Andes strain as the culprit, marking the only hantavirus strain known to transmit between humans. According to a document presented to South Africa's parliament, the Andes strain is unique in its ability to spread from person to person. South African health authorities confirmed that both confirmed patients tested positive for this strain after analysis by the National Institute for Communicable Diseases.
The Andes strain is exceptionally rare among hantaviruses. While over 20 other strains exist, they only spread through rodent contact. Infection from those strains can cause illness but not onward transmission to others.
Outbreak Timeline
As of May 4, 2026, seven cases have been identified, including two laboratory-confirmed hantavirus cases and five suspected cases. Among these, three deaths occurred, one patient is critically ill, and three individuals reported mild symptoms. Illness onset ranged from April 6 to April 28. The ship departed from Argentina, a country already grappling with its own outbreak. Between July 2025 and January 2026, at least 20 deaths from hantavirus were reported in Argentina, with a 34% fatality rate—higher than the historical average of 10–32%.
The Andes strain was first identified in Chile and Argentina in 1995, primarily carried by the pygmy rice rat. Its fatality rate is alarming: nearly 40% of those infected die, almost double the 25% fatality rate of the Sin Nombre strain found in the southwestern United States. The disease progresses rapidly, characterized by fever, gastrointestinal symptoms, and swift progression to pneumonia, acute respiratory distress syndrome, and shock.
Hantavirus Symptoms
According to the World Health Organization, symptoms typically appear between one and eight weeks after exposure and include fever, headache, muscle aches, and gastrointestinal issues such as abdominal pain, nausea, or vomiting. These nonspecific signs make early diagnosis challenging. In the Americas, where hantavirus cardiopulmonary syndrome occurs, the disease can quickly escalate to cough, shortness of breath, fluid accumulation in the lungs, and shock. Intensive care with oxygen and ventilation becomes critical for survival.
In Europe and Asia, hantavirus attacks the kidneys instead. The WHO notes that later stages may involve low blood pressure, bleeding disorders, and kidney failure. Thus, depending on the strain, the virus can destroy either the lungs or the kidneys, both potentially fatal without appropriate medical support.
