Fourth King County resident monitored in cruise ship hantavirus outbreak

A fourth King County resident is now being monitored after health officials traced a cruise-linked Andes hantavirus outbreak from a Dutch-flagged ship to a Johannesburg-to-Amsterdam flight and into Washington state. Public Health - Seattle & King County said the newest person was not on the MV Hondius, but shared the flight with an ill passenger who was removed before takeoff.

That detail widened an already complex public-health response. Earlier county notices had identified three residents under monitoring, including two people exposed on the plane and one person who had been aboard the ship. Public Health - Seattle & King County said the resident who was on the ship remained asymptomatic and was being monitored at the national quarantine center at the University of Nebraska Medical Center. Officials said there were no confirmed Andes virus cases in King County.

Washington State Department of Health said the public risk remained very low, even as investigators followed two separate hantavirus events involving different virus strains and exposure circumstances. The agency said one out of three people diagnosed with hantavirus pulmonary syndrome have died, underscoring why local, state and federal officials moved quickly to isolate exposures and monitor travelers who crossed borders and state lines.

The cruise outbreak has drawn in the Centers for Disease Control and Prevention, the World Health Organization and the European Centre for Disease Prevention and Control. CDC said its Health Alert Network advisory was issued May 8 after WHO was notified of the cluster on May 2 and confirmed Andes virus on May 6. As of May 8, WHO had reported eight cases, including three deaths. WHO’s May 4 update listed seven cases, including three deaths, one critically ill patient and three people with mild symptoms.

WHO said the MV Hondius carried 147 passengers and crew when it departed Ushuaia, Argentina, on April 1, 2026, then traveled to Antarctica, South Georgia Island, Tristan da Cunha, Saint Helena and Ascension Island. Illness onsets occurred between April 6 and April 28 and included fever, gastrointestinal symptoms, pneumonia, acute respiratory distress syndrome and shock. ECDC’s May 15 update said the outbreak had grown to 11 reported cases, including eight confirmed, two probable and one inconclusive, with three deaths and no new cases in the latest update.

Andes virus remains the only known hantavirus that spreads person to person, but that transmission is rare and usually requires prolonged close contact with an ill person. For officials now tracing exposure chains across flights, ports and quarantine centers, the outbreak has become a test of how quickly cruise sanitation, rodent-control measures and international notification systems can contain a virus before it reaches the wider public.