A fourth local resident is being monitored after they were aboard a flight with an ill cruise ship passenger, according to Public Health.
SEATTLE — A fourth person in King County is being monitored for symptoms after a possible exposure to the deadly hantavirus infection on a recent flight, according to Public Health – Seattle & King County.
The person was not on the MV Hondius cruise ship, but they were aboard a flight with an ill cruise ship passenger before takeoff; the ill passenger was removed from the flight before the plane departed from Johannesburg for Amsterdam.
The Washington State Department of Health and the Centers for Disease Control and Prevention (CDC) notified the local health agency about the monitoring on Thursday, May 14.
Public Health said the fourth person is considered “low risk” of infection because they were not seated near the ill passenger. The King County resident remains asymptomatic and health officials are monitoring for any developing symptoms.
Three additional King County residents are also being monitored for possible Andes type of hantavirus infections after exposure.
Of those people, two King County residents were sitting near the ill cruise ship passenger on the Johannesburg flight prior to the sick passenger’s removal. Another King County resident who was on the MV Hondius cruise ship is also being monitored at the national quarantine center in Nebraska.
None of the King County residents under monitoring have any symptoms and there are no Andes type infections in the county, according to Public Health.
An unrelated hantavirus case
In Chelan County, a resident has tested positive for the Sin Nombre virus strain of hantavirus, according to the Chelan-Douglas Health District.
However, the case has no connection to the cruise ship outbreak and was not cause by any other worldwide cases.
Officials said the person’s exposure likely happened in or around the home where they encountered mice. Hantavirus originates from contact with wild rodents and can lead to severe, even deadly sickness.
The Sin Nombre virus, which has already been reported in Washington, cannot be spread person to person. About two cases are reported per year in Washington state, mainly in eastern Washington counties, according to a 2025 state Department of Health report.
Three cases were reported in King and Skagit counties from November 2016 to June 2017, leading to the death of one man.
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