Key takeaways from WHO briefing on hantavirus cruise ship outbreak

Health Key takeaways from WHO briefing on hantavirus cruise ship outbreak The U.S. and Argentina, both recent WHO dropouts, are cooperating in the response Manage alerts for this article Email this article Share this article By Helen BranswellMay 7, 2026 Infectious Diseases Correspondent Helen BranswellHelen Branswell covers issues broadly related to infectious diseases, including outbreaks, preparedness, research, and vaccine development. Follow her on Mastodon and Bluesky. You can reach Helen on Signal at hbranswell.01. The MV Hondius, the cruise ship that has garnered global attention because of an apparent outbreak of person-to-person spread hantavirus infections, is on the move. At the request of Tedros Adhanom Ghebreyesus, the World Health Organization’s director-general, Spain has agreed to let the ship dock off Tenerife, in the Canary Islands. The ship is expected to arrive on Sunday. This outbreak — the first time hantavirus has been suspected of transmitting on a cruise ship — is an evolving situation. It’s also one that is going to take weeks to resolve, because of the long incubation period of hantaviruses. And it could be months before scientists piece together how the virus got on the boat and whether all the subsequent cases were people infected through contact with other people or whether rodents — which are known to carry hantaviruses — that were on board played any part.Advertisement The WHO held a press conference about the situation Thursday. Here are five key takeaways: Planning is underway to get the remaining passengers and crew off the ship At present no one who is ill is onboard the ship, Maria Van Kerkhove, a top WHO official, said during the press conference. Three people who were ill, including the ship’s doctor, were evacuated to the Netherlands. Efforts are underway to assess the health status of the remaining passengers and crew and how likely they were to have interacted with known cases. Roughly 145 people from 23 countries are currently on the ship.Advertisement The WHO and the home countries of the passengers and crew are working on plans to get these people off the ship and safely home. “We are working with all of the countries who have nationalities that are on board to discuss the plans for the safe journey of those patients home,” said Van Kerkhove, the agency’s acting director of epidemic and pandemic management. Tedros alluded to the stress people on the ship are under, noting he had spoken to the ship’s captain earlier Thursday and had been informed the mood onboard the MV Hondius has improved since the ship is again on the move. The evidence the outbreak started before the voyage began grows stronger The working hypothesis has been that the first two cases in this outbreak — a couple who boarded the ship in Argentina — were infected before the cruise began. The incubation period for hantavirus infections is long; it can take up to six weeks from exposure to the virus to the development of symptoms. So the notion the couple might have been infected before they embarked is plausible. Tedros said that the couple were on a bird-watching expedition before they boarded the ship. That trip took them through parts of Chile, Uruguay, and Argentina, “which included visits to sites where the species of rats that’s known to carry Andes virus was present.” The Andes virus, which is responsible for this outbreak, is the only hantavirus known to have the capacity to transmit from person to person. Even then, recorded transmission events have been rare. Tedros said the WHO is working with the Argentine government to get a better handle on the couple’s movements before they boarded the ship. The U.S. and Argentina, which recently exited the WHO, are cooperating with the agency Both the United States and Argentina have told the WHO they have quit the global health organization. But both are cooperating with the international efforts to investigate the source of this outbreak and safely repatriate people from the ship, WHO officials stressed. “In terms of collaboration with U.S. and U.S. institutions, it has been going very well,” said Abdi Mahamud, director of WHO’s health emergency alert and response operations. “The information flow is there, transparent and frank information sharing.”Advertisement Some of the information exchanges are occurring through the International Health Regulations, a treaty aimed at protecting the world from disease outbreaks that can cross borders. The U.S. is still a party to the IHR. Anaïs Legand, WHO’s technical lead on viral hemorrhagic fevers, said she has had excellent collaboration with her counterpart at the Centers for Disease Control and Prevention. “We have very positive, regular interactions almost every single day.” Tedros said that the WHO is sharing information with the U.S. in the way it always has, and is getting information in return through IHR channels. He said he hoped the U.S. and Argentina would reconsider withdrawing from the global health agency. “Viruses don’t care about our politics and they don’t care about our borders,” he said. “The best immunity we have is solidarity.” Apart from the setting, there’s no evidence new disease dynamics are at work here The Andes virus has been seen in rare instances to transmit from person to person. The largest known outbreak occurred in Epuyén, Argentina, in 2018-2019. It involved 34 confirmed cases, 11 of whom died. It’s believed there were four generations of infections before the outbreak was contained. It’s still early days in the investigation of this outbreak, but so far experts believe the only new thing here is the fact that the outbreak happened on a ship. “There is no indication to date that there is something further unusual, but obviously the fact that it happened in a cruise ship with people from different nationalities is something that we haven’t seen before,” Legand said. Mahamud said even though the circumstances are slightly different, conditions on a ship in some ways mirror those in other instances in which the Andes virus has been seen to transmit person to person, pointing to the Epuyén outbreak, which is thought to have taken off at a large and crowded birthday party. “So we are in a similar situation right now, a cluster in a confined space with close contact,” Mahamud said. Legand said laboratories in South Africa, Switzerland, and Senegal are working to generate full genetic sequences of the viruses retrieved from the confirmed cases to see if anything has changed or to determine if they can provide clues as to how transmission occurred. Advertisement There are likely to be lots of suspected cases popping up for a while Every day, it seems, there are reports of possible cases being admitted to hospitals for observation and assessment in various parts of the world. A flight attendant who worked on a plane that transported one of the confirmed cases. (It’s not yet clear if this person is infected.) A Swiss man who was on the ship early in the voyage but disembarked before the outbreak was discovered. (He is a confirmed case.) Given the number of people who were on the ship for part or all of its journey, the fact that the ship stopped in several ports, and that people aboard came from at least 28 countries ranging from St. Kitts and Nevis to Denmark, New Zealand, and Ukraine, many people may have had some contact or will have some contact with people who were on the MV Hondius. Potential contacts will be instructed to be on the alert for symptoms for weeks — symptoms that in the early stages of infection can seem like those associated with a number of other respiratory diseases. Some cases, like that of the Swiss man, may turn out to be confirmed. Some, maybe many, will not. But following up on all these possible cases is what public health does, Van Kerkhove said. global health, infectious diseases, public health Submit a correction requestReprints Helen Branswell Infectious Diseases Correspondent Helen Branswell covers issues broadly related to infectious diseases, including outbreaks, preparedness, research, and vaccine development. Follow her on Mastodon and Bluesky. You can reach Helen on Signal at hbranswell.01. Newsletter Understand how science, health policy, and medicine shape the world every day Recommended The Readout LOUD May 7, 2026 Seaport’s IPO adventure, obesity pill battles, and Makary’s troubles In the Lab May 7, 2026 Science is becoming less disruptive. Is an aging workforce to blame? Advertisement Exclusive May 7, 2026 Official leading CDC’s cruise ship program retires D.C. Diagnosis May 7, 2026 STAT Plus: More political interference at the FDA? 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