International health authorities are monitoring the spread of hantavirus, which was detected on board the cruise ship MV Hondius, after some passengers left the ship before it was diagnosed.

Since April 2026, an outbreak of the Andes strain of hantavirus has been reported on the Dutch cruise ship MV Hondius. This is the only known variant of the virus, which can, in rare cases, be transmitted from person to person. The disease is severe: patients have reported fever, gastrointestinal symptoms, rapid development of pneumonia, and acute respiratory distress syndrome.

According to The Guardian, as of May 6, five cases of infection have been confirmed, three are suspected, and three people have died. Among the dead is a Dutch couple. Additionally, a patient in Switzerland, hospitalized at the University Hospital of Zurich, has also been confirmed as infected with hantavirus after returning from a ship.

The key concern for epidemiologists is that approximately 30 passengers disembarked the ship on April 24 at St. Helena—almost two weeks after the first death on board—and it was only on May 2 that doctors first confirmed hantavirus in one of the passengers. Therefore, some passengers had already returned home long before the outbreak was officially declared. Singapore authorities reported that they were tracking two citizens who disembarked at St. Helena and returned home via South Africa.

The Dutch Ministry of Health said a flight attendant from the flight, which briefly carried one of the infected passengers, was being tested in an isolation ward at an Amsterdam hospital. If tested positive, she would be the first known case of infection not directly on board the MV Hondius.

According to the WHO, 146 people from 23 countries, including 17 US citizens, currently remain on board under strict precautionary measures. The ship is heading to the Canary Islands, but Fernando Clavijo, president of the autonomous community of the Canary Islands, refused to accept the ship, citing the threat to the local population. The WHO responded by stating that Spain has a "moral and legal obligation" to accept the ship, which has several Spanish citizens on board.

WHO Director-General for Preparedness and Response Dr. Abdirahman Mahamoud stated that the organization expects the outbreak to be limited, provided public health measures and international solidarity are observed. The US CDC also emphasized that the risk to the general public remains extremely low.