Everything You Need to Know about How Hantavirus is Spreading
The chain of sick and dying passengers stretching from a cruise ship in the Atlantic to hospital wards in South Africa, Switzerland, Germany, and the Netherlands tells an unsettling story about how quickly a rodent-borne virus can go global.
A rare and deadly virus has emerged far from its South American homeland, spreading among passengers aboard a cruise ship anchored off the coast of Africa and setting off an urgent, multi-nation public health response, with victims now scattered across South Africa, Switzerland, the Netherlands, and Germany.
In April 2026, an outbreak of hantavirus was identified on the cruise ship MV Hondius, anchored off the coast of Praia, Cape Verde. According to the World Health Organization, as of May 5, 2026, seven cases of the acute respiratory virus had been identified, including three deaths.
What makes this outbreak particularly alarming to scientists is not just the death toll, it's which strain is responsible.
On May 6, it was confirmed that the strain was the rare Andes variant, which is capable of human-to-human transmission in rare cases, associated with close contact.
A Ship, a Voyage, and a Hidden Virus
There were 149 people on board the MV Hondius, representing 23 different nationalities, including passengers from nine EU member states: Belgium, France, Germany, Greece, Ireland, the Netherlands, Poland, Portugal, and Spain.
The Hondius set off from southern Argentina on April 1. On April 6, a 70-year-old Dutch man fell ill with fever, headache, and diarrhea. He would become the outbreak's index case. The index case died on April 11, 2026, while on board; his remains are currently in Saint Helena pending repatriation to the Netherlands.
The tragedy then followed his wife ashore. An adult female, a close contact of the first case, went ashore at Saint Helena on April 24 with gastrointestinal symptoms. She subsequently deteriorated during a flight to Johannesburg, South Africa, on April 25, and died upon arrival at the emergency department on April 26. Her case was subsequently confirmed by PCR on May 4. Contact tracing for passengers on that flight has been initiated.
A third patient was also evacuated to South Africa. An adult male presented to the ship's doctor on April 24 with febrile illness, shortness of breath, and signs of pneumonia. His condition worsened on April 26, and he was medically evacuated from Ascension Island to South Africa on April 27, where he is currently hospitalized in an intensive care unit. Laboratory testing conducted in South Africa confirmed hantavirus infection in this patient, who was critically ill and in intensive care. WHO's Van Kerkhove said this patient is "improving."
A third fatality, a German woman, died on the ship on Saturday after falling ill with signs of pneumonia. Her body remained on the ship.
One critical breakthrough came from South Africa's laboratories. Health officials in South Africa tested the British man in intensive care for hantavirus after tests for other ailments came back negative. They received a positive result for hantavirus on Saturday, 21 days after the first passenger died. The positive test then prompted South African health authorities to test the Dutch woman's body posthumously, which also came back positive.
Officials in South Africa, where two of the ship's passengers were evacuated, have begun contact tracing as a precautionary measure.
The Virus Spreads Across Continents
The outbreak did not stay on the ship. Twenty-six passengers who were potentially exposed to hantavirus had already disembarked on April 24, about two weeks before formal reports were filed. Among these passengers were Americans who are now back in the United States, and health officials are working to contact these individuals for testing and monitoring.
A previous passenger on the ship also presented himself to a hospital in Zurich after receiving an email from the ship's operator about the health situation. He is now receiving care there.
In the late afternoon of May 5, three infected individuals were removed from the ship and transported by air ambulance from Praia International Airport to the Netherlands and Germany, where they reside.
In two concerning developments today:
The Strain That Breaks the Rules
In most cases, hantaviruses result in what's called a dead-end infection, a human gets infected after contact with animal droppings but doesn't pass it on to anyone else. Andes virus is an exception. It can spread between people, giving it the potential to spark outbreaks.
"There are like 20 to 30 different species of hantavirus worldwide that can cause human disease, and there is only one of those species, the Andes virus, which is found in Argentina and Chile, that has been implicated in human-to-human transmission," said Dr. Emily Abdoler, a clinical associate professor of medicine at the University of Michigan.
The Andes strain carries a fatality rate of approximately 40%, and contracting it requires prolonged, close contact with infected individuals. The incubation period can range from one to eight weeks.
That long and silent incubation period is precisely what allowed the virus to travel so far before being identified and it is what now has health authorities across three continents racing to locate and test exposed passengers before any window of opportunity closes.
As Dr. Abdoler explained, with human-to-human spread possible, "taking people off the ship doesn't stop the spread" - requiring isolation and quarantine of contacts even beyond the ship itself.
No Treatment, No Vaccine
There is no treatment for hantavirus pulmonary syndrome; supportive care remains the primary tool for improving a patient's chances of survival. Early supportive care and immediate referral to a facility with a complete ICU can improve survival rates.
WHO has classified hantaviruses as emerging priority pathogens with high potential to spark international public health emergencies, because of how serious these infections can be.