Rare Hantavirus Andes strain linked to illness and death on cruise ship: Symptoms, fatality rate and other details

When the MV Hondius cruise ship started reporting deaths in early May, the cause wasn't something most people had heard of before. Soon it was confirmed to be hantavirus. This is a virus that normally lives in rodents and somehow found a way to devastate a ship with nearly 150 people on board.


Days later, reports said it was the Andes strain of the virus, the only strain that causes human to human transmission, was behind the outbreak. "A document presented to South Africa's parliament on Wednesday morning says the Andes strain is "the only strain that is known to cause human to human transmission," BBC reported. The report quoted South African health authorities saying that Andes strain was found in both confirmed patients after tests conducted by the country's National Institute for Communicable Diseases.





The Andes strain is the only hantavirus capable of human-to-human transmission, an extremely rare occurrence. Every other hantavirus strain, and there are more than 20 of them, spreads only through rodents. You catch it, you might get sick, but you won't pass it to anyone else.

The outbreak timeline

As of May 4, 2026, seven cases (two laboratory confirmed cases of hantavirus and five suspected cases) have been identified, including three deaths, one critically ill patient and three individuals reporting mild symptoms, with illness onset occurring between April 6 and April 28. The ship departed from Argentina, a country that's currently dealing with its own ongoing outbreak. Between July 2025 and January 2026, at least 20 deaths from the virus were reported in Argentina, with a 34% fatality rate between January 2025 and January 2026, compared with historical national averages of 10–32%.

The Andes strain was first identified in Chile and Argentina back in 1995, and it's primarily carried by a species of rodent called the pygmy rice rat.

The fatality rate is legitimately scary. The Andes strain kills nearly 40% of those infected. That's almost double the fatality rate of the Sin Nombre strain found in the southwestern U.S., which sits at around 25%. When someone gets infected, the disease progresses fast. Illness was characterized by fever, gastrointestinal symptoms, rapid progression to pneumonia, acute respiratory distress syndrome and shock.

What hantavirus symptoms look like

According to the WHO, symptoms "usually begin between one and eight weeks after exposure" and "typically include fever, headache, muscle aches and gastrointestinal symptoms such as abdominal pain, nausea or vomiting." That description could apply to a dozen different illnesses, which is why early diagnosis is actually pretty difficult.

In the Americas, where the more dangerous form called hantavirus cardiopulmonary syndrome exists, the WHO says "the disease may progress rapidly to cough, shortness of breath, accumulation of fluid in the lungs and shock." That's the phase where people end up in intensive care. The lung fills with fluid, breathing becomes impossible without help, and the body goes into shock. At that point, without ICU-level support—oxygen, ventilation, the works—survival becomes unlikely.

In Europe and Asia, the virus attacks kidneys instead. The WHO notes that "later stages may include low blood pressure, bleeding disorders and kidney failure." So you've got a virus that either destroys your lungs or your kidneys depending on which strain you catch, and both versions can kill you.