An unprecedented outbreak at sea

On April 1, 2026, the polar cruise ship MV Hondius departed Ushuaia, Argentina, bound for Antarctica and remote Atlantic islands. Nearly 150 passengers and crew of 23 nationalities were on board. On April 11, a 70-year-old Dutch citizen died aboard. His wife, also infected, died in South Africa on April 26. On May 2, a German woman died on the vessel.

What began as an isolated incident on a vessel now reaches more than twelve countries across four continents. Thirty passengers disembarked at Saint Helena on April 24, ten days before the WHO confirmed the hantavirus outbreak on May 4. The Dutch government puts that figure closer to 40. Health authorities are tracing citizens in the Netherlands, Germany, the United Kingdom, Switzerland, France, Canada, Singapore, the United States, South Africa, and Argentina, among others.

As of May 7, the World Health Organization reports eight cases linked to the outbreak: five confirmed and three suspected, with three deaths. On May 6, health authorities confirmed the virus was the Andes strain, the only hantavirus with documented human-to-human transmission. The ship is sailing toward Tenerife, Spain, expected to arrive this weekend.

Science magazine described the episode as “uncharted territory” for researchers. Until this outbreak, no documented hantavirus cluster had occurred at sea.

Hantavirus belongs to the family Hantaviridae, within the order Bunyavirales. It is a single-stranded, negative-sense RNA virus with a segmented genome encoding the nucleocapsid, surface glycoproteins, and viral polymerase. Old World hantaviruses, present in Asia and Europe, cause hemorrhagic fever with renal syndrome (HFRS). New World hantaviruses, present in the Americas, cause hantavirus cardiopulmonary syndrome (HCPS). The Andes virus belongs to this second group and is endemic to cordilleran regions of Argentina and Chile.

The natural reservoir is the sigmodontine rodent Oligoryzomys longicaudatus. Transmission to humans occurs principally through inhalation of aerosols from dried rodent excreta in enclosed or semi-enclosed spaces. The Andes virus carries an unprecedented feature among hantaviruses: it can transmit from person to person, but only under conditions of extremely close and prolonged contact, such as sharing a bed, sexual intimacy, or direct caregiving.

The incubation period ranges from 7 to 39 days, with a median around 18 days. The disease evolves in two phases. A prodromal phase of three to five days presents with fever, chills, myalgia, and gastrointestinal symptoms. The cardiopulmonary phase begins abruptly with cough, dyspnea, and rapid hemodynamic deterioration, leading to pulmonary edema, acute respiratory distress syndrome, cardiogenic shock, and multiorgan failure in severe cases.

Historic mortality from Andes virus ranges between 30 and 40 percent, with higher figures in patients without timely access to intensive care. No specific antiviral is approved for HCPS. Ribavirin has shown no utility. Management remains supportive:........

© The Times of Israel (Blogs)