Three passengers were evacuated from a cruise ship after a hantavirus outbreak was confirmed aboard, and health officials have now identified at least one additional case in Switzerland, according to reporting by NBC News and CBS News.
The evacuations took place as authorities worked to contain what appears to be an unusual shipboard spread of a virus that typically passes from rodents to humans through contact with infected droppings, urine, or saliva. Person-to-person transmission of hantavirus is considered rare, making the cluster of cases aboard a single vessel notable to health experts.
Health experts speaking to CBS News said the most likely explanation for how the virus moved through the ship involves passengers encountering contaminated rodent material somewhere during the voyage, possibly in a port of call or in an area of the ship where rodents had been present. Investigators have not publicly confirmed the exact route of exposure.
Hantavirus causes a serious respiratory illness known as hantavirus pulmonary syndrome, which can be fatal. Symptoms typically begin with fever, muscle aches, and fatigue before progressing in some cases to severe respiratory distress. There is no specific antiviral treatment approved for the disease, and care is largely supportive.
The confirmation of a new case in Switzerland suggests at least one infected passenger disembarked and traveled before the illness was identified. Swiss health authorities have been notified, though details on that patient's condition were not immediately available in the reports.
The cruise line involved has not been identified by name in public reporting, and the full passenger count exposed or screened has not been disclosed. Authorities have not said how many people aboard were tested or are under observation.
Hantavirus outbreaks linked to travel are uncommon. Most cases in Europe and the Americas are traced to rural or semi-rural settings where people come into contact with wild rodents. A shipboard cluster, if confirmed as such, would be a medically unusual event.
Public health officials have not issued a broad travel warning related to the ship as of the time of reporting.