Hantavirus symptoms detected in two Americans; one shows only mild illness

The Department of Health and Human Services confirmed Sunday evening that among the 17 Americans evacuated from the MV Hondius, one passenger had mild symptoms, and another tested "mildly PCR positive" for the Andes virus strain. As per Reuters, both are traveling in biocontainment units aboard a medical repatriation flight headed to the United States, departing from Spain's Canary Islands where the cruise ship arrived early Sunday.


The distinction between the two cases matters. One American is symptomatic but hasn't tested positive yet, symptoms can take weeks to show up in testing. The other has tested positive but appears to have a lighter viral load, suggesting the infection may be caught earlier or developing less severely. Hantavirus pulmonary syndrome can kill up to 38% of people who develop respiratory symptoms, though experts emphasize the actual mortality rate may be lower since mild cases often go undiagnosed.






The ship, which departed from Argentina in April and visited remote South Atlantic locations including Antarctica, has been linked to at least eight hantavirus cases overall, including three confirmed deaths. The first person to fall ill, a Dutch man, developed symptoms aboard the ship around April 6 while apparently asymptomatic during boarding. He subsequently died, as did his wife and a German passenger. The virus spread to close contacts aboard the vessel, with the ship's doctor also becoming infected.


What makes this outbreak unusual is the rare person-to-person transmission. Hantaviruses typically spread through contact with infected rodents' urine, droppings, or saliva. The Andes virus is the only known hantavirus strain capable of spreading between people, though it requires close, prolonged contact, sharing utensils, respiratory secretions, contaminated bedding, or direct physical contact. A Swiss tour guide who disembarked in Saint Helena and flew home also tested positive, suggesting transmission occurred aboard the ship during the voyage.


The 17 American passengers are headed to the University of Nebraska Medical Center's specialized National Quarantine Unit in Omaha. The facility, which treated Diamond Princess cruise ship passengers at the start of the COVID-19 pandemic and Ebola patients in 2014, has the specialized equipment and expertise needed for potential hantavirus cases. Most passengers will undergo initial clinical assessment and then continue monitoring at home for 42 days—the full incubation period for the virus.

The U.S. State Department's airlift will transport passengers to the ASPR Regional Emerging Special Pathogen Treatment Center (RESPTC) at the University of Nebraska Medical Center ⁠in Omaha, Nebraska, and the passenger with mild symptoms will be taken to a second RESPTC.


Health officials stressed that most passengers are asymptomatic and classified as low-risk. The CDC emphasized this isn't a traditional quarantine but rather careful monitoring during the virus's incubation window.