Eighteen Americans who were aboard a cruise ship tied to a hantavirus outbreak have been flown back to the United States, health officials say. The U.S. State Department evacuated the group from Tenerife on May 10; two of the returnees are being cared for in biocontainment units as a precaution. One of those two tested positive for hantavirus and the other has only mild symptoms. The remainder are being monitored at specialized treatment centers: 16 patients at an ASPR Regional Emerging Special Pathogen Treatment Center in Omaha, Nebraska, and two at a similar center in Atlanta.
The outbreak was traced to the Dutch-flagged m/v Hondius, which left southern Argentina on April 1 with roughly 150 passengers and crew for an Antarctic expedition. Eleven days into the voyage a 70-year-old man developed fever, headaches and abdominal pain and subsequently died. Several other passengers later fell ill, and the World Health Organization identified the ship as the scene of a hantavirus cluster. All passengers have since disembarked and are being repatriated to their home countries.
Reports that people were being flown home stirred concerns about another pandemic, but infectious disease specialists say those fears are disproportionate. Lina Moses, an epidemiologist and disease ecologist who studies rodent-borne infections, noted that increased case detection shows surveillance is working: people on the ship were being monitored and identified as symptoms appeared.
Hantaviruses are usually spread when people inhale dust contaminated with urine, droppings or nesting materials from infected rodents. Most hantaviruses are not transmitted between people. However, one South American strain, the Andes virus, is unique among hantaviruses in that it has been linked to human-to-human transmission in the past.
Investigators believe the most likely scenario for what happened on the Hondius is that someone carrying Andes virus boarded the vessel and passed it to other passengers, with the ship’s confined spaces and shared facilities facilitating transmission. Experts say this pattern—spread among close contacts in cramped conditions or at gatherings—is consistent with earlier Andes virus clusters and is not unexpected.
Even so, the Andes virus is not as easily spread as respiratory viruses such as SARS-CoV-2. Researchers emphasize that its transmissibility is considerably lower than what was seen early in the COVID-19 pandemic. The virus’s incubation period can be long—reported to range from about 4 to 42 days—which has raised questions about asymptomatic spread. But available evidence indicates viral load tends to peak during the early symptomatic phase, when ill patients have fever and respiratory signs. That means the people most likely to transmit the virus are also the ones who generally become noticeably sick and are more likely to be isolated or hospitalized, which limits opportunities for onward spread.
In short, Andes virus infections can be severe and sometimes fatal, and person-to-person transmission has been documented, but such spread appears to require prolonged, close, often intimate contact. That combination of factors makes a fast-moving, COVID-like global pandemic unlikely. As one researcher put it, these are dangerous viruses that deserve careful management, but current patterns and what is known about the virus do not point to an imminent public health threat on the scale of COVID-19.
Health officials continue to investigate the Hondius outbreak, monitor contacts and repatriate passengers. For most people, routine travel and daily life are not expected to change because of this incident, though public health authorities will keep watching for further cases and provide guidance if needed.
