The World Health Organization announced on Thursday that the hantavirus outbreak linked to the cruise ship MV Hondius is over, after the final person under quarantine completed isolation, tested negative, and returned home. No new cases have been reported since 25 May, leaving the total at 13 infections and three fatalities. More than 650 contacts across 33 countries and territories were traced and monitored without further transmission, prompting WHO Director-General Tedros Adhanom Ghebreyesus to declare the cluster closed.

The outbreak was caused by the Andes strain of hantavirus, the only known variant capable of limited human-to-human transmission. Typically, hantaviruses spread to humans through inhalation of aerosolised rodent excreta, but this strain’s ability to pass between people in close contact elevated the public-health response. The Dutch-flagged vessel departed Ushuaia, Argentina, on 1 April, and cases emerged during its South Atlantic voyage. After the ship was diverted to Tenerife, Spanish authorities facilitated the safe disembarkation and repatriation of passengers and crew under strict biosecurity protocols, an effort singled out for praise by WHO officials. The ship later docked in Rotterdam for disinfection.

The response drew on the International Health Regulations, with health authorities from Argentina, Cabo Verde, Chile, the Netherlands, South Africa, and the United Kingdom coordinating contact tracing. Viewed from Geneva, the episode demonstrated the capacity of multilateral surveillance to contain a rare pathogen with pandemic potential, though the WHO consistently assessed the risk to the general population as low. The cluster’s high case fatality ratio—three deaths among 13 cases—underscored the severity of Andes virus infection, which can cause severe respiratory illness and for which no vaccine or specific treatment exists.

While the outbreak is closed, the WHO is now coordinating a 21-country observational study to map the clinical progression of hantavirus disease. The findings are expected to inform the development of diagnostics, therapeutics, and vaccines. Health officials in South America, where the virus is endemic in rodent populations, stress that sustained surveillance remains essential. The next milestone will be the study’s interim data, which could guide future outbreak response protocols.