Hantavirus outbreak kills three on cruise ship, WHO says risk remains low

A cluster of hantavirus infections linked to an international cruise has left at least three people dead and several others ill, prompting a coordinated multi-country public health response, the World Health Organization (WHO) has said.

The outbreak, reported to WHO on May 2, involves a Dutch-flagged cruise ship carrying 147 passengers and crew from 23 nationalities. As of May 4, seven cases have been identified — two laboratory-confirmed and five suspected — including one critically ill patient currently in intensive care.

According to WHO, symptoms among affected passengers ranged from fever and gastrointestinal distress to rapidly progressing pneumonia, acute respiratory failure and shock. Illness onset dates back to between April 6 and April 28.

The vessel, which departed Ushuaia, Argentina, on April 1, had travelled across the South Atlantic with stops in Antarctica, South Georgia, Tristan da Cunha, Saint Helena and Ascension Island. It is currently moored off Cabo Verde, where medical teams are assessing passengers and collecting samples for further testing.

Details released by WHO show that the first recorded case involved a male passenger who developed fever and diarrhoea on April 6 and died five days later after developing severe respiratory complications. A second case — a woman who had close contact with the first patient — died in South Africa after falling ill during a flight from Saint Helena. Laboratory tests later confirmed hantavirus infection.

A third patient, also evacuated to South Africa, remains in critical condition, while another passenger died on May 2 after developing pneumonia. Three additional suspected cases with milder symptoms remain onboard.

Health authorities in Cabo Verde, the Netherlands, Spain, South Africa and the United Kingdom are working with WHO to investigate the outbreak, trace contacts and manage cases. Some passengers have been advised to remain in their cabins and observe strict hygiene and distancing measures, while discussions are ongoing to support medical evacuations.

Hantavirus is a rare but potentially fatal disease typically transmitted to humans through contact with infected rodents or their droppings. Although person-to-person transmission is uncommon, it has been documented in limited cases involving a specific strain known as the Andes virus.

WHO said the source of exposure in this outbreak has not yet been established, including whether infections occurred during the voyage or prior to boarding in South America.

Despite the fatalities, the agency assessed the overall risk to the global population as low, noting that hantavirus infections are relatively uncommon worldwide.

“There are no specific antiviral treatments or vaccines currently approved for hantavirus pulmonary syndrome, but early supportive care significantly improves survival,” WHO said, urging vigilance among travellers and healthcare providers.

Passengers and crew have been advised to monitor symptoms for up to 45 days, maintain strict hygiene practices and report any illness promptly.

WHO added that it does not recommend any travel or trade restrictions at this time, but will continue to monitor the situation as investigations proceed.