The World Health Organization (WHO) is monitoring an outbreak of severe respiratory illness linked to hantavirus aboard the Dutch-flagged expedition cruise ship MV Hondius after seven cases, including three deaths, were reported as of May 4, 2026.
According to WHO, the cluster was first reported on May 2 through the National International Health Regulations (IHR) Focal Point of the United Kingdom. The outbreak currently includes two laboratory-confirmed cases of hantavirus infection and five suspected cases. One patient remains critically ill in intensive care, while three others are experiencing milder symptoms.
The ship departed Ushuaia on April 1 and travelled through the South Atlantic with stops including mainland Antarctica, South Georgia, Nightingale Island, Tristan da Cunha, Saint Helena and Ascension Island. As of May 4, the vessel was moored off the coast of Cabo Verde.
The vessel is carrying 88 passengers and 59 crew members representing 23 nationalities.
WHO said illness onset among affected passengers occurred between April 6 and April 28 and was characterised by fever, gastrointestinal symptoms, rapid progression to pneumonia, acute respiratory distress syndrome and shock.
The first reported case involved an adult male who developed fever, headache and diarrhoea on April 6 while onboard. His condition rapidly deteriorated into respiratory distress and he died on April 11. No laboratory testing was performed at the time.
A second passenger, an adult female and close contact of the first case, developed gastrointestinal symptoms while ashore in Saint Helena on April 24. Her condition worsened during a flight to Johannesburg, South Africa, and she later died on April 26. Laboratory testing confirmed hantavirus infection on May 4. Authorities have initiated contact tracing for passengers on the flight.
Both individuals had reportedly travelled through South America, including Argentina, before boarding the cruise ship.
A third confirmed case involved a male passenger who presented with fever, pneumonia and respiratory symptoms on April 24. After his condition worsened, he was medically evacuated from Ascension Island to South Africa on April 27 and remains hospitalised in intensive care. PCR testing confirmed hantavirus infection on May 2.
A fourth passenger died on May 2 after developing pneumonia-like symptoms, fever and general illness. Three additional suspected cases remain onboard and are undergoing medical evaluation in Cabo Verde.
WHO stated that coordinated response measures involving authorities from Cabo Verde, the Netherlands, Spain, South Africa and the United Kingdom are currently underway. These include epidemiological investigations, isolation measures, laboratory testing, medical evacuation support and international information sharing through the IHR network.
Laboratory investigations are being conducted at the National Institute for Communicable Diseases in South Africa, with additional samples being sent to the Institut Pasteur de Dakar in Senegal for further testing.
Passengers onboard have been advised to remain in their cabins where possible, maintain physical distancing and monitor symptoms for up to 45 days.
WHO explained that hantavirus infections are rare but potentially severe zoonotic diseases primarily transmitted through contact with urine, saliva or faeces of infected rodents. Symptoms can include fever, muscle pain, gastrointestinal illness and severe respiratory complications.
The organisation noted that while human-to-human transmission is uncommon, limited transmission has previously been reported in outbreaks involving the Andes virus strain in South America.
WHO currently assessed the global public health risk from the outbreak as low and has advised against imposing travel or trade restrictions related to the incident.
The organisation further emphasised the importance of infection prevention measures, environmental sanitation, rodent exposure prevention and early detection of symptoms among passengers, crew and healthcare workers involved in the response.
