GENEVA — Health authorities across more than 30 countries launched an emergency operation Thursday to identify and contact thousands of passengers who sailed aboard the cruise liner MV Adriatic Star after at least nine confirmed cases of hantavirus infection were traced to a voyage that departed Buenos Aires on April 19 and called at ports in Uruguay, Brazil, and Chile before returning to port on May 3. The World Health Organization characterized the situation as a public health event of international concern and convened an emergency advisory committee to coordinate the global tracing effort, one of the largest passenger-contact operations undertaken by international health authorities since the early years of the previous decade.
Hantavirus, a rare but potentially deadly pathogen transmitted primarily through contact with infected rodent droppings, saliva, or urine, does not typically spread from person to person, making a cruise ship setting an unusual and deeply alarming context for a cluster of this magnitude. Epidemiologists from the WHO’s emerging diseases division said preliminary evidence suggested passengers may have been exposed through contaminated food stores in the ship’s lower cargo holds, where inspectors found clear evidence of rodent infestation after the vessel was quarantined at the port of Montevideo on Wednesday. Full results of environmental sampling were expected within 48 to 72 hours, at which point authorities hoped to pinpoint the precise exposure location and timeline more accurately.
The MV Adriatic Star carried 1,847 passengers and 712 crew members during the two-week voyage. Health officials said that identifying and reaching all former passengers was complicated by the multinational character of the passenger list, with travelers from at least 34 nationalities aboard, many of whom had already flown home to destinations as far apart as Japan, Germany, Canada, and South Africa. The ship’s operator, Oceanic Voyages International, said it was cooperating fully with authorities and had provided complete passenger manifests and contact details to the WHO and to all relevant national health ministries within 12 hours of the quarantine order being issued.
Of the nine confirmed cases, six involved passengers and three were crew members, all of whom had worked in or near the ship’s food storage and preparation areas. Two patients remained in critical condition in intensive care units in Santiago and Sao Paulo as of Thursday evening. Hantavirus pulmonary syndrome, the severe form of the disease, carries a case fatality rate of between 30 and 40 percent without prompt medical intervention, according to WHO data. All nine confirmed patients developed symptoms including fever, severe muscle aches, and progressive shortness of breath within 10 to 14 days of the voyage’s departure, a timeline consistent with the pathogen’s known incubation period. Seventeen additional individuals who reported possible symptoms were under medical observation as of Thursday, though none had yet tested positive.
Dr. Yusuf Abara, coordinator of the WHO’s vector-borne and zoonotic disease unit, urged any former passenger or crew member experiencing respiratory symptoms, unexplained fever, or persistent fatigue to seek medical care immediately and to inform their treating physician of the voyage. “The number of confirmed cases may rise as tracing efforts expand,” Abara told reporters at a briefing in Geneva. “We are asking national health authorities to treat this with the same urgency they would apply to any serious respiratory outbreak.” Argentina’s national health ministry announced it had activated emergency protocols at major international airports and ports and established a dedicated toll-free hotline staffed around the clock for former passengers and their families.
Public health experts noted that hantavirus outbreaks aboard passenger vessels are exceptionally rare and said the incident raised urgent questions about biosecurity and pest-control standards across the cruise industry. “The presence of a rodent infestation significant enough to infect multiple passengers and crew members represents a serious and potentially systemic failure of sanitation protocols,” said Dr. Claire Fontaine, an epidemiologist at the European Centre for Infectious Disease Research. “Regulatory bodies should conduct a comprehensive audit of pest-control requirements across commercial maritime operators without delay.” Oceanic Voyages International said it had immediately placed the MV Adriatic Star out of service and retained an independent marine biosecurity firm to conduct a full vessel inspection.
Authorities sought to reassure the wider public that the overall risk to people who had not traveled on the vessel was negligible, as hantavirus is not transmitted through casual contact, shared airspace, or community settings. The focus of international health coordination remained squarely on locating the remaining passengers and crew members, conducting medical assessments, and determining the precise mechanism and timeline of exposure aboard the ship. The WHO’s emergency committee said it would issue a further guidance update within 72 hours and would maintain daily contact with the health ministries of all countries whose nationals had traveled on the voyage.