A hantavirus outbreak aboard the luxury cruise ship MV Hondius has killed three people, including a 69-year-old Dutch woman, her husband, and a German passenger. Five of eight suspected cases have been confirmed; the virus is believed to have originated during a birdwatching excursion in Argentina where passengers were exposed to infected rodents. This marks the first documented human-to-human transmission of hantavirus, though WHO officials stress transmission requires close contact and poses far lower pandemic risk than COVID-19.