What Happened on the Hantavirus Cruise, According to a Doctor on Board

When Stephen Kornfeld set sail aboard the MV Hondius in early April, his grand plan for the cruise was to add as many new species as possible to his birding list. A medical oncologist based in Bend, Oregon, Kornfeld is also an avid birder—second on e Bird’s renowned rankings of birders worldwide—and the ship would visit several remote islands, where he might spot some of the globe’s most obscure avians. But last week, Kornfeld’s trip took an unexpected twist: He stepped in to care for three people thought to be sick with hantavirus, a severe respiratory pathogen that can kill roughly half of the people it infects. Kornfeld was, and still is, “a passenger on this boat,” he told me. “But I became the doctor on this boat.”Since the MV Hondius departed, at least eight people have come down with suspected or confirmed cases of hantavirus; three have died. People typically get infected by the virus via the aerosolized feces or other bodily secretions of infected rodents. But the World Health Organization has confirmed that this hantavirus is a species called Andes virus, which has sometimes spread person to person, under conditions of close and prolonged contact—such as, say, on a cruise ship with about 150 people on board.A month ago, as the cruise departed from Argentina, Kornfeld and the other passengers—among them, dozens of birders—were buzzing about the whales, seals, and dolphins they spotted cavorting in the South Atlantic Ocean, and gossiping about the adventures ahead. When a 70-year-old Dutch man, one of the birders, died aboard on April 11, Kornfeld and the others were shaken but considered the incident a freak accident, with no implications for anyone else on board. But then, roughly two weeks later, the Dutch man’s wife fell sick, too, dying shortly after she was taken off the ship. After another birder, a British man, grew feverish and began struggling to breathe, he was evacuated to a South African ICU, where he remains in care.By the end of April, three ot